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Background: The COVID-19 pandemic has disrupted routine measles immunisation and supplementary immunisation activities (SIAs) in most countries including Kenya. We assessed the risk of measles outbreaks during the pandemic in Kenya as a case study for the African Region.Methods: Combining measles serological data, local contact patterns, and vaccination coverage into a cohort model, we predicted the age-adjusted population immunity in Kenya and estimated the probability of outbreaks when contact-reducing COVID-19 interventions are lifted. We considered various scenarios for reduced measles vaccination coverage from April 2020.Results: In February 2020, when a scheduled SIA was postponed, population immunity was close to the herd immunity threshold and the probability of a large outbreak was 34% (8-54). As the COVID-19 contact restrictions are nearly fully eased, from December 2020, the probability of a large measles outbreak will increase to 38% (19-54), 46% (30-59), and 54% (43-64) assuming a 15%, 50%, and 100% reduction in measles vaccination coverage. By December 2021, this risk increases further to 43% (25-56), 54% (43-63), and 67% (59-72) for the same coverage scenarios respectively. However, the increased risk of a measles outbreak following the lifting of all restrictions can be overcome by conducting a SIA with ≥ 95% coverage in under-fives.Conclusion: While contact restrictions sufficient for SAR-CoV-2 control temporarily reduce measles transmissibility and the risk of an outbreak from a measles immunity gap, this risk rises rapidly once these restrictions are lifted. Implementing delayed SIAs will be critical for prevention of measles outbreaks given the roll-back of contact restrictions in Kenya. [ABSTRACT FROM AUTHOR]

Background: During November 2019-October 2021, a pediatric influenza vaccination demonstration project was conducted in four sub-counties in Kenya. The demonstration piloted two different delivery strategies: year-round vaccination and a four-month vaccination campaign. Our objective was to compare the costs of both delivery strategies., Methods: Cost data were collected using standardized questionnaires and extracted from government and project accounting records. We reported total costs and costs per vaccine dose administered by delivery strategy from the Kenyan government perspective in 2021 US$. Costs were separated into financial costs (monetary expenditures) and economic costs (financial costs plus the value of existing resources). We also separated costs by administrative level (national, regional, county, sub-county, and health facility) and program activity (advocacy and social mobilization; training; distribution, storage, and waste management; service delivery; monitoring; and supervision)., Results: The total estimated cost of the pediatric influenza demonstration project was US$ 225,269 (financial) and US$ 326,691 (economic) for the year-round delivery strategy (30,397 vaccine doses administered), compared with US$ 214,753 (financial) and US$ 242,385 (economic) for the campaign strategy (25,404 doses administered). Vaccine purchase represented the largest proportion of costs for both strategies. Excluding vaccine purchase, the cost per dose administered was US$ 1.58 (financial) and US$ 5.84 (economic) for the year-round strategy and US$ 2.89 (financial) and US$ 4.56 (economic) for the campaign strategy., Conclusions: The financial cost per dose was 83% higher for the campaign strategy than the year-round strategy due to larger expenditures for advocacy and social mobilization, training, and hiring of surge staff for service delivery. However, the economic cost per dose was more comparable for both strategies (year-round 22% higher than campaign), balanced by higher costs of operating equipment and monitoring activities for the year-round strategy. These delivery cost data provide real-world evidence to inform pediatric influenza vaccine introduction in Kenya., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Introduction: In 2016, the Kenya National Immunization Technical Advisory Group requested additional programmatic and cost effectiveness data to inform the choice of strategy for a national influenza vaccination program among children aged 6-23 months of age. In response, we conducted an influenza vaccine demonstration project to compare the performance of a year-round versus campaign-mode vaccination strategy. Findings from this demonstration project will help identify essential learning lessons for a national program., Methods: We compared two vaccine delivery strategies: (i) a year-round vaccination strategy where influenza vaccines were administered throughout the year at health facilities. This strategy was implemented in Njoro sub-county in Nakuru (November 2019 to October 2021) and Jomvu sub-county in Mombasa (December 2019 to October 2021), (ii) a campaign-mode vaccination strategy where vaccines were available at health facilities over four months. This strategy was implemented in Nakuru North sub-county in Nakuru (June to September 2021) and Likoni sub-county in Mombasa (July to October 2021). We assessed differences in coverage, dropout rates, vaccine wastage, and operational needs., Results: We observed similar performance between strategies in coverage of the first dose of influenza vaccine (year-round strategy 59.7 %, campaign strategy 63.2 %). The coverage obtained in the year-round sub-counties was similar (Njoro 57.4 %; Jomvu 63.1 %); however, more marked differences between campaign sub-counties were observed (Nakuru North 73.4 %; Likoni 55.2 %). The campaign-mode strategy exceeded the cold chain capacity of participating health facilities, requiring thrice monthly instead of once monthly deliveries, and was associated with a two-fold increase in workload compared to the year-round strategy (168 vaccines administered per day in the campaign strategy versus 83 vaccines administered per day in the year-round strategy)., Conclusion: Although both strategies had similar coverage levels, the campaign-mode strategy was associated with considerable operational needs that could significantly impact the immunization program., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: SSC has since left the US CDC and is currently an employee of Sanofi Vaccines, Lyon, France., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Pneumococcal conjugate vaccines are an expensive component of the routine immunization schedule. Fractional-dose regimens may be one option to increase the sustainability of the vaccine program., Methods: We assessed whether the immunogenicity of fractional doses of the 10-valent and 13-valent pneumococcal conjugate vaccines (PCV10 [GSK] and PCV13 [Pfizer], respectively) would be noninferior to that of the full doses and analyzed the prevalence of vaccine-serotype carriage. We randomly assigned healthy infants in Kenya to one of seven equal-sized trial groups. Participants in groups A through F were assigned to receive either a fractional or full dose of PCV10 or PCV13, administered as two primary doses plus one booster dose. In group A, participants received a full dose of PCV13; group B, a 40% dose of PCV13; group C, a 20% dose of PCV13; group D, a full dose of PCV10; group E, a 40% dose of PCV10; and group F, a 20% dose of PCV10. Participants in the seventh group (group G) received a full dose of PCV10 as three primary doses without a booster. Immunogenicity was assessed 4 weeks after the primary series of doses and 4 weeks after the booster dose. Noninferiority could be declared 4 weeks after the primary series if the difference in the percentage of participants with a threshold response was not more than 10% and 4 weeks after administration of the booster if the ratio of the geometric mean concentration (GMC) of IgG was more than 0.5. A vaccine dose was prespecified as noninferior if it met the noninferiority criterion for at least 8 of the 10 vaccine types in the PCV10 groups or at least 10 of the 13 vaccine types in the PCV13 groups. Carriage was assessed when participants were 9 months and 18 months of age., Results: In the per-protocol analysis, 40% of a full dose of PCV13 met the noninferiority criterion for 12 of 13 serotypes after the primary series and for 13 of 13 serotypes after the booster. The immunogenicity of the 20% dose of PCV13 and of the 40% and 20% doses of PCV10 was not noninferior to that of the full doses. Vaccine serotype-type carriage prevalence was similar across the PCV13 groups at 9 months and 18 months of age., Conclusions: In a three-dose schedule (two primary doses and a booster), 40% doses of PCV13 were noninferior to full doses for all included serotypes. Lower doses of PCV13 and PCV10 did not meet the criteria for noninferiority. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT03489018; Pan African Clinical Trial Registry number, PACTR202104717648755.)., (Copyright © 2024 Massachusetts Medical Society.)

Background: Influenza is a significant contributor to acute respiratory infections (ARI), and children < 5 years are at increased risk of severe influenza disease. In Kenya the influenza vaccine is not included in the Kenya Expanded Programme on Immunization (KEPI). To inform roll-out of a national influenza vaccination program, we implemented an influenza vaccine demonstration project in Nakuru and Mombasa counties in Kenya from 2019 to 2021 and set out to establish factors driving influenza vaccine acceptance and hesitancy among caregivers of children aged 6-23 months., Methods: Using semi-structured questionnaires, we conducted eight focus group discussions among community members and twelve key informant interviews among healthcare workers to elicit both lay and expert opinions. Thematic analysis of the interviews was conducted using the World Health Organization's "3 Cs" model of vaccine hesitancy to determine reasons for acceptance or hesitancy of the influenza vaccine., Results: The influenza vaccine was well received among community members and healthcare workers though concerns were raised. Vaccine hesitancy was fuelled by misconceptions about reasons for introducing the vaccine (confidence), perceptions that influenza was not a serious disease (complacency) and administrative fees required at some facilities (convenience). Despite the use of various advocacy, communication and social mobilisation strategies targeted at educating the community on the influenza disease and importance of vaccination, there remained a perception of inadequate reach of the sensitization among some community members. Contextual factors such as the COVID-19 pandemic affected uptake, and parents expressed concern over the growing number of vaccines recommended for children., Conclusion: Despite lingering concerns, caregivers had their children vaccinated indicating that vaccine hesitancy exists, even among those who accepted the vaccine for their children. Efforts targeted at increasing confidence in and reducing misconceptions towards vaccines through effective communication strategies, are likely to lead to increased vaccine uptake., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Background: Vaccination remains the most effective means of reducing the burden of infectious disease among children. It is estimated to prevent between two to three million child deaths annually. However, despite being a successful intervention, basic vaccination coverage remains below the target. About 20 million infants are either under or not fully vaccinated, most of whom are in Sub-Saharan Africa region. In Kenya, the coverage is even lower at 83% than the global average of 86%. The objective of this study is to explore the factors that contribute to low demand or vaccine hesitancy for childhood and adolescent vaccines in Kenya., Methods: The study used qualitative research design. Key Informant Interviews (KII) was used to obtain information from national and county-level key stakeholders. In-depth Interviews (IDI) was done to collect opinions of caregivers of children 0-23 months and adolescent girls eligible for immunization, and Human papillomavirus (HPV) vaccine respectively. The data was collected at the national level and counties such as Kilifi, Turkana, Nairobi and Kitui. The data was analyzed using thematic content approach. A total of 41 national and county-level immunization officials and caregivers formed the sample., Results: Insufficient knowledge about vaccines, vaccine supply issues, frequent healthcare worker's industrial action, poverty, religious beliefs, inadequate vaccination campaigns, distance to vaccination centers, were identified as factors driving low demand or vaccine hesitancy against routine childhood immunization. While factors driving low uptake of the newly introduced HPV vaccine were reported to include misinformation about the vaccine, rumors that the vaccine is a form of female contraception, the suspicion that the vaccine is free and available only to girls, poor knowledge of cervical cancer and benefits of HPV vaccine., Conclusions: Rural community sensitization on both routine childhood immunization and HPV vaccine should be key activities post COVID-19 pandemic. Likewise, the use of mainstream and social media outreaches, and vaccine champions could help reduce vaccine hesitancy. The findings are invaluable for informing design of context-specific interventions by national and county-level immunization stakeholders. Further studies on the relationship between attitude towards new vaccines and connection to vaccine hesitancy is necessary., (© 2023. The Author(s).)

Introduction: The high burden of respiratory syncytial virus (RSV) infection in young children disproportionately occurs in low- and middle-income countries (LMICs). The PROUD (Preventing RespiratOry syncytial virUs in unDerdeveloped countries) Taskforce of 24 RSV worldwide experts assessed key needs for RSV prevention in LMICs, including vaccine and newer preventive measures., Methods: A global, survey-based study was undertaken in 2021. An online questionnaire was developed following three meetings of the Taskforce panellists wherein factors related to RSV infection, its prevention and management were identified using iterative questioning. Each factor was scored, by non-panellists interested in RSV, on a scale of zero (very-low-relevance) to 100 (very-high-relevance) within two scenarios: (1) Current and (2) Future expectations for RSV management., Results: Ninety questionnaires were completed: 70 by respondents (71.4% physicians; 27.1% researchers/scientists) from 16 LMICs and 20 from nine high-income (HI) countries (90.0% physicians; 5.0% researchers/scientists), as a reference group. Within LMICs, RSV awareness was perceived to be low, and management was not prioritised. Of the 100 factors scored, those related to improved diagnosis particularly access to affordable point-of-care diagnostics, disease burden data generation, clinical and general education, prompt access to new interventions, and engagement with policymakers/payers were identified of paramount importance. There was a strong need for clinical education and local data generation in the lowest economies, whereas upper-middle income countries were more closely aligned with HI countries in terms of current RSV service provision., Conclusion: Seven key actions for improving RSV prevention and management in LMICs are proposed., Competing Interests: The reviewer PAP declared a past co-authorship with the author(s) FMT to the handling. XCE and BP have received research funding and/or compensation as advisor/lecturer from AbbVie and AstraZeneca. JF and BRG, working for Violicom and former company, have previously received payment from AbbVie and AstraZeneca for work on various projects. MCN reports grants from the Bill & Melinda Gates Foundation, European & Developing Countries Clinical Trials Partnership, Pfizer, AstraZeneca and Sanofi-Pasteur; and personal fees from Pfizer and Sanofi-Pasteur. RTS has received fees for Advisory Board meetings and lectures for Sanofi-Pasteur, AstraZeneca, Janssen, and AbbVie. QB serves in the Independent Data Monitoring Committee (IDMC) for Respiratory Syncytial Virus (RSV) vaccine development for the protection of infants (since October 2015) (GlaxoSmithKline -GSK). JP reports grants to his institution from MedImmune, Merck, Sanofi Pasteur and AbbVie, and personal fees from AbbVie, Merck and AstraZeneca. JMP reports grants to his institution from MedImmune. HJZ has received funding for RSV-related research studies from Pfizer, AstraZeneca, Merck and the Bill & Melinda Gates Foundation. AM has received research funding from Merck and Janssen and compensation as advisor/lecturer from Sanofi-Pasteur and AstraZeneca. IM has been an investigator on studies funded by MedImmune, Regeneron, and Boehringer. MAS has received research funding from Janssen and compensation as advisor/lecturer from AbbVie, Sanofi-Pasteur and AstraZeneca. All declarations made by authors outside of the submitted work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2022 Carbonell-Estrany, Simões, Bont, Gentile, Homaira, Scotta, Stein, Torres, Sheikh, Broor, Khuri-Bulos, Nokes, Munywoki, Bassat, Sharma, Basnet, Garba, De Jesus-Cornejo, Lupisan, Nunes, Divarathna, Fullarton, Rodgers-Gray, Keary, Reñosa, Verwey, Moore, Noordeen, Kabra, do Vale, Paternina-De La Ossa, Mariño, Figueras-Aloy, Krilov, Berezin, Zar, Paudel, Safadi, Dbaibo, Jroundi, Jha, Rafeek, Pinheiro, Bracht, Muthugala, Lanari, Martinón-Torres, Mitchell, Irimu, Pandey, Krishnan, Mejias, Santos Corrêa Da Costa, Shrestha, Pernica, Cotrim de Carvalho, Jalango, Ibrahim, Ewa, Ensinck, Ulloa-Gutierrez, Miralha, Lucion, Hassan, Akhtar, Aleem, Chowdhury, Rojo, Sande, Musau, Zaman, Arlant, Ghimire, Price, Subedi, Brenes-Chacon, Goswami, Rahman, Hossain, Chisti, Vain, Lim, Chiu, Papenburg, Juarez, Senaratne, Arunasalam, Strand, Ayuk, Ogunrinde, Tavares, Garba, Garba, Dawa, Gordon, Osoro, Agoti, Nyawanda, Ngama, Tabu, Mathew, Cornacchia, Rai, Jain, Giongo and Paes.)

Introduction: Measles is a vaccine-preventable disease whose elimination depends on the measles-containing vaccine (MCV) coverage of ≥95% in the population. In 2020, Kenya reported 597 cases, an increase of 158 cases from those reported in 2019. This study aimed to estimate the measles vaccine coverage and factors associated with its uptake in Cherangany Sub County., Methods: We conducted a cross-sectional study using cluster sampling in the Cherangany Sub County of Trans Nzoia County in May 2021. We enrolled eligible children aged between 24-59 months and interviewed their caregivers using a structured questionnaire. We conducted descriptive, bivariate, and multivariate analyses. We used Prevalence Odds Ratio (POR) at bivariate and adjusted POR (aPOR) at multivariate with their corresponding 95% confidence interval as the measure of association. We regarded the variables with a p-value of less <0.05 at the multivariate level as independently associated with immunization status., Results: We recruited 536 eligible children. The median age of the participants was 39 months (Interquartile Range 31-50). The coverage was 96.6% (518/536) for MCV dose one (MCV 1), and 56.2% (301/536) MCV dose two (MCV 2). At the bivariate level, family monthly income (POR 2.32, 95% CI 1.14-4.72), child vaccination status for other scheduled vaccines (POR 0.21, 95% CI 0.07-0.66), caregiver's level of education (POR = 1.82, 95% CI 1.29-2.57), knowledge of the vaccine-preventable diseases (POR = 0.55, 95% CI 0.38-0.80), and knowledge of the number of MCV scheduled doses (POR = 0.13, 95% CI 0.09-0.02) were significantly associated with MCV uptake. The Caregiver's knowledge on the number of MCV scheduled doses (POR = 5.73, 95% CI 3.48-9.45) and children whose birth order was ≤5th born (POR = 0.5, 95% CI 0.22-0.95) were significantly associated with MCV uptake at the multivariate analysis., Conclusion: The MCV 2 coverage was lower than the WHO recommended ≥ 95%. Lack of knowledge of the number of MCV scheduled doses and the child's birth order in the family are factors associated with not being fully vaccinated against measles., Recommendation: There is a need to strengthen the defaulter tracing system to follow up the children who default after receiving MCV 1, focusing interventions on the identified factors., Competing Interests: The authors have declared that no competing interests exist.

Global childhood vaccination coverage has stagnated over the past decade and raising coverage will require a collection of approaches since no single approach has been suitable for all countries or situations. The American Red Cross has developed a 5-Point Plan a to geolocate under-vaccinated children and determine the reasons why they miss vaccination by capitalizing on the Red Cross Movement's large cadres of trusted community volunteers. The Plan was piloted in Bobasi sub-county in Western Kenya, with volunteers seeking to conduct a face-to-face interview in all households, visiting over 60,000 over 7 days. Six pockets of 233 children without a home-based vaccination record or missing an age-appropriate dose of Penta1, Penta3 or measles-containing vaccine were identified. Three activities were carried out to learn why these children were not vaccinated: 1) one-on-one interviews and 2) focus group discussions with the caregivers of the under-vaccinated children and 3) interviews with healthcare workers who vaccinate in Bobasi. Complacency was commonly reported by caregivers during one-on-one interviews while bad staff attitude or practice was most frequently reported in focus group discussions; health staff reported caregiver hesitency, not knowing vaccination due date and vaccine stock-outs as the most common reasons for caregivers to not have their child vaccinated. As reasons varied across the three different activities, the different perspectives and approaches helped characterize vaccination barriers. Civil society organizations working together with the Ministry of Health can provide valuable information for immunization managers to act on., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: The RTS,S/ASO1E malaria vaccine is being piloted in three countries-Ghana, Kenya, and Malawi-as part of a coordinated evaluation led by the World Health Organization, with support from global partners. This study estimates the costs of continuing malaria vaccination upon completion of the pilot evaluation to inform decision-making and planning around potential further use of the vaccine in pilot areas., Methods: We used an activity-based costing approach to estimate the incremental costs of continuing to deliver four doses of RTS,S/ASO1E through the existing Expanded Program on Immunization platform, from each government's perspective. The RTS,S/ASO1E pilot introduction plans were reviewed and adapted to identify activities for costing. Key informant interviews with representatives from Ministries of Health (MOH) were conducted to inform the activities, resource requirements, and assumptions that, in turn, inform the analysis. Both financial and economic costs per dose, cost of delivery per dose, and cost per fully vaccinated child (FVC) are estimated and reported in 2017 USD units., Results: At a vaccine price of $5 per dose and assuming the vaccine is donor-funded, our estimated incremental financial costs range from $1.70 (Kenya) to $2.44 (Malawi) per dose, $0.23 (Malawi) to $0.71 (Kenya) per dose delivered (excluding procurement add-on costs), and $11.50 (Ghana) to $13.69 (Malawi) per FVC. Estimates of economic costs per dose are between three and five times higher than financial costs. Variations in activities used for costing, procurement add-on costs, unit costs of per diems, and allowances contributed to differences in cost estimates across countries., Conclusion: Cost estimates in this analysis are meant to inform country decision-makers as they face the question of whether to continue malaria vaccination, should the intervention receive a positive recommendation for broader use. Additionally, important cost drivers for vaccine delivery are highlighted, some of which might be influenced by global and country-specific financing and existing procurement mechanisms. This analysis also adds to the evidence available on vaccine delivery costs for products delivered outside the standard immunization schedule., Competing Interests: The authors have read the journal’s policy and have the following potential competing interests: RB, CO, CP, JB, KO, RM, SG, and FM are employed by PATH while engaged in this research. CT, JC, and RJ are employed by the Ministry of Health in Kenya. EM, and TM are employed by the Ministry of Health in Malawi. GB, JD, and KA are employed by the Ministry of Health in Ghana. AL and WM are consultants with the Levin and Morgan LLC. This does not alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Background: In November 2016, the Kenya National Vaccines and Immunization Programme conducted an assessment of missed opportunities for vaccination (MOV) using the World Health Organization (WHO) MOV methodology. A MOV includes any contact with health services during which an eligible individual does not receive all the vaccine doses for which he or she is eligible., Methods: The MOV assessment in Kenya was conducted in 10 geographically diverse counties, comprising exit interviews with caregivers and knowledge, attitudes, and practices (KAP) surveys with health workers. On the survey dates, which covered a 4-day period in November 2016, all health workers and caregivers visiting the selected health facilities with children <24 months of age were eligible to participate. Health facilities (n = 4 per county) were purposively selected by size, location, ownership, and performance. We calculated the proportion of MOV among children eligible for vaccination and with documented vaccination histories (i.e., from a home-based record or health facility register), and stratified MOV by age and reason for visit. Timeliness of vaccine doses was also calculated., Results: We conducted 677 age-eligible children exit interviews and 376 health worker KAP surveys. Of the 558 children with documented vaccination histories, 33% were visiting the health facility for a vaccination visit and 67% were for other reasons. A MOV was seen in 75% (244/324) of children eligible for vaccination with documented vaccination histories, with 57% (186/324) receiving no vaccinations. This included 55% of children visiting for a vaccination visit and 93% visiting for non-vaccination visits. Timeliness for multi-dose vaccine series doses decreased with subsequent doses. Among health workers, 25% (74/291) were unable to correctly identify the national vaccination schedule for vaccines administered during the first year of life. Among health workers who reported administering vaccines as part of their daily work, 39% (55/142) reported that they did not always have the materials they needed for patients seeking immunization services, such as vaccines, syringes, and vaccination recording documents., Conclusions: The MOV assessment in Kenya highlighted areas of improvement that could reduce MOV. The results suggest several interventions including standardizing health worker practices, implementing an orientation package for all health workers, and developing a stock management module to reduce stock-outs of vaccines and vaccination-related supplies. To improve vaccination coverage and equity in all counties in Kenya, interventions to reduce MOV should be considered as part of an overall immunization service improvement plan., Competing Interests: The authors have declared that no competing interests exist.

Background: Monovalent rotavirus vaccine, Rotarix (GlaxoSmithKline), was introduced in Kenya in July 2014 and is recommended to infants as oral doses at ages 6 and 10 weeks. A multisite study was established in 2 population-based surveillance sites to evaluate vaccine impact on the incidence of rotavirus-associated hospitalizations (RVHs)., Methods: Hospital-based surveillance was conducted from January 2010 to June 2017 for acute diarrhea hospitalizations among children aged <5 years in 2 health facilities in Kenya. A controlled interrupted time-series analysis was undertaken to compare RVH pre- and post-vaccine introduction using rotavirus-negative cases as a control series. The change in incidence post-vaccine introduction was estimated from a negative binomial model that adjusted for secular trend, seasonality, and multiple health worker industrial actions (strikes)., Results: Between January 2010 and June 2017 there were 1513 and 1652 diarrhea hospitalizations in Kilifi and Siaya; among those tested for rotavirus, 28% (315/1142) and 23% (197/877) were positive, respectively. There was a 57% (95% confidence interval [CI], 8-80%) reduction in RVHs observed in the first year post-vaccine introduction in Kilifi and a 59% (95% CI, 20-79%) reduction in Siaya. In the second year, RVHs decreased further at both sites, 80% (95% CI, 46-93%) reduction in Kilifi and 82% reduction in Siaya (95% CI. 61-92%); this reduction was sustained at both sites into the third year., Conclusions: A substantial reduction in RVHs and all-cause diarrhea was observed in 2 demographic surveillance sites in Kenya within 3 years of vaccine introduction., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: Rotavirus remains a leading cause of pediatric diarrheal illness and death worldwide. Data on rotavirus vaccine effectiveness in sub-Saharan Africa are limited. Kenya introduced monovalent rotavirus vaccine (RV1) in July 2014. We assessed RV1 effectiveness against rotavirus-associated hospitalization in Kenyan children., Methods: Between July 2014 and December 2017, we conducted surveillance for acute gastroenteritis (AGE) in 3 Kenyan hospitals. From children age-eligible for ≥1 RV1 dose, with stool tested for rotavirus and confirmed vaccination history we compared RV1 coverage among rotavirus positive (cases) vs rotavirus negative (controls) using multivariable logistic regression and calculated effectiveness based on adjusted odds ratio., Results: Among 677 eligible children, 110 (16%) were rotavirus positive. Vaccination data were available for 91 (83%) cases; 51 (56%) had 2 RV1 doses and 33 (36%) 0 doses. Among 567 controls, 418 (74%) had vaccination data; 308 (74%) had 2 doses and 69 (16%) 0 doses. Overall 2-dose effectiveness was 64% (95% confidence interval [CI], 35%-80%); effectiveness was 67% (95% CI, 30%-84%) for children aged <12 months and 72% (95% CI, 10%-91%) for children aged ≥12 months. Significant effectiveness was seen in children with normal weight for age, length/height for age and weight for length/height; however, no protection was found among underweight, stunted, or wasted children., Conclusions: RV1 in the Kenyan immunization program provides significant protection against rotavirus-associated hospitalization which persisted beyond infancy. Malnutrition appears to diminish vaccine effectiveness. Efforts to improve rotavirus uptake and nutritional status are important to maximize vaccine benefit., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: In 2016, Kenya conducted a study of missed opportunities for vaccination (MOV)-when eligible children have contact with the health system but are not fully vaccinated-to explore some of the reasons for persistent low vaccination coverage. This paper details the qualitative findings from that assessment., Methods: Using the World Health Organization MOV methodology, teams conducted focus group discussions among caregivers and health workers and in-depth interviews of key informants in 10 counties in Kenya. Caregivers of children <24 months of age visiting the selected health facilities on the day of the assessment were requested to participate in focus group discussions. Health workers were purposively sampled to capture a broad range of perspectives. Key informants were selected based on their perceived insight on immunization services at the county, sub-county, or health facility level., Results: Six focus group discussions with caregivers, eight focus group discussions with health workers, and 35 in-depth interviews with key informants were completed. In general, caregivers had positive attitudes toward healthcare and vaccination services, but expressed a desire for increased education surrounding vaccination. In order to standardize vaccination checks at all health facility visits, health workers and key informants emphasized the need for additional trainings for all staff members on immunization. Health workers and key informants also highlighted the negative impact of significant understaffing in health facilities, and the persistent challenge of stock-outs of vaccines and vaccination-related supplies., Conclusions: Identified factors that could contribute to MOV include a lack of knowledge surrounding vaccination among caregivers and health workers, inadequate number of health workers, and stock-outs of vaccines or vaccination-related materials. In addition, vaccination checks outside of vaccination visits lacked consistency, leading to MOV in non-vaccinating departments. Qualitative assessments could provide a starting point for understanding and developing interventions to address MOV in other countries., Competing Interests: The authors have declared that no competing interests exist.

Prompt provision of post-exposure-prophylaxis (PEP) including vaccines and rabies immunoglobulin (RIG) to persons bitten by suspect rabid dogs is a key strategy to eliminating human deaths from dog-mediated rabies in Kenya by 2030. We assessed the availability, forecasting and supply chain logistics for rabies PEP in Kenya, compared with the system used for vaccines in the expanded program of immunization (routine vaccines). Semi-structured questionnaires capturing data on forecasting, procurement, distribution, cold chain and storage, monitoring and reporting for routine vaccines and rabies vaccines and RIG were administered to 35 key personnel at the national, county, sub-county and health facility levels in five counties. Results showed large variability in PEP availability (stockouts ranged from 3 to 36 weeks per year) with counties implementing rabies elimination activities having shorter stockouts. PEP is administered intramuscularly using the 5-dose Essen regimen (day 0, 3, 7, 14 and 28). PEP costs to bite patients were reported to range from 10 to 15 US dollars per dose; RIG was seldom available. A less robust supply and logistics infrastructure is used for rabies PEP compared to routine vaccines. Forecasting and monitoring mechanisms for rabies PEP was poor in the study counties. The supply of vaccines from the national to the sub-national level is mainly through two government agencies and a private agency. Since government decentralization, the National Vaccine and Immunization Program has remained as the main supplier of the routine vaccines, playing a lesser role in the supply of rabies biologicals. Adoption of the dose-saving intradermal route for PEP administration, reduction of PEP costs to patients, and placing rabies vaccines within the routine vaccines supply and logistics system would significantly improve PEP availability and accessibility to persons at risk of rabies; a critical step to achieving elimination of human deaths from rabies., (Copyright © 2019. Published by Elsevier Ltd.)

Background: Ten-valent pneumococcal conjugate vaccine (PCV10), delivered at 6, 10, and 14 weeks of age was introduced in Kenya in January, 2011, accompanied by a catch-up campaign in Kilifi County for children aged younger than 5 years. Coverage with at least two PCV10 doses in children aged 2-11 months was 80% in 2011 and 84% in 2016; coverage with at least one dose in children aged 12-59 months was 66% in 2011 and 87% in 2016. We aimed to assess PCV10 effect against nasopharyngeal carriage and invasive pneumococcal disease (IPD) in children and adults in Kilifi County., Methods: This study was done at the KEMRI-Wellcome Trust Research Programme among residents of the Kilifi Health and Demographic Surveillance System, a rural community on the Kenyan coast covering an area of 891 km 2 . We linked clinical and microbiological surveillance for IPD among admissions of all ages at Kilifi County Hospital, Kenya, which serves the community, to the Kilifi Health and Demographic Surveillance System from 1999 to 2016. We calculated the incidence rate ratio (IRR) comparing the prevaccine (Jan 1, 1999-Dec 31, 2010) and postvaccine (Jan 1, 2012-Dec 31, 2016) eras, adjusted for confounding, and reported percentage reduction in IPD as 1 minus IRR. Annual cross-sectional surveys of nasopharyngeal carriage were done from 2009 to 2016., Findings: Surveillance identified 667 cases of IPD in 3 211 403 person-years of observation. Yearly IPD incidence in children younger than 5 years reduced sharply in 2011 following vaccine introduction and remained low (PCV10-type IPD: 60·8 cases per 100 000 in the prevaccine era vs 3·2 per 100 000 in the postvaccine era [adjusted IRR 0·08, 95% CI 0·03-0·22]; IPD caused by any serotype: 81·6 per 100 000 vs 15·3 per 100 000 [0·32, 0·17-0·60]). PCV10-type IPD also declined in the post-vaccination era in unvaccinated age groups (<2 months [no cases in the postvaccine era], 5-14 years [adjusted IRR 0·26, 95% CI 0·11-0·59], and ≥15 years [0·19, 0·07-0·51]). Incidence of non-PCV10-type IPD did not differ between eras. In children younger than 5 years, PCV10-type carriage declined between eras (age-standardised adjusted prevalence ratio 0·26, 95% CI 0·19-0·35) and non-PCV10-type carriage increased (1·71, 1·47-1·99)., Interpretation: Introduction of PCV10 in Kenya, accompanied by a catch-up campaign, resulted in a substantial reduction in PCV10-type IPD in children and adults without significant replacement disease. Although the catch-up campaign is likely to have brought forward the benefits by several years, the study suggests that routine infant PCV10 immunisation programmes will provide substantial direct and indirect protection in low-income settings in tropical Africa., Funding: Gavi, The Vaccine Alliance and The Wellcome Trust of Great Britain., (Copyright © 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: In 2009, Gavi, the World Bank, and donors launched the pneumococcal Advance Market Commitment, which helped countries access more affordable pneumococcal vaccines. As many low-income countries begin to reach the threshold at which countries transition from Gavi support to self-financing (3-year average gross national income per capita of US$1580), they will need to consider whether to continue pneumococcal conjugate vaccine (PCV) use at full cost or to discontinue PCV in their childhood immunisation programmes. Using Kenya as a case study, we assessed the incremental cost-effectiveness of continuing PCV use., Methods: In this modelling and cost-effectiveness study, we fitted a dynamic compartmental model of pneumococcal carriage to annual carriage prevalence surveys and invasive pneumococcal disease (IPD) incidence in Kilifi, Kenya. We predicted disease incidence and related mortality for either continuing PCV use beyond 2022, the start of Kenya's transition from Gavi support, or its discontinuation. We calculated the costs per disability-adjusted life-year (DALY) averted and associated 95% prediction intervals (PI)., Findings: We predicted that if PCV use is discontinued in Kenya in 2022, overall IPD incidence will increase from 8·5 per 100 000 in 2022, to 16·2 per 100 000 per year in 2032. Continuing vaccination would prevent 14 329 (95% PI 6130-25 256) deaths and 101 513 (4386-196 674) disease cases during that time. Continuing PCV after 2022 will require an estimated additional US$15·8 million annually compared with discontinuing vaccination. We predicted that the incremental cost per DALY averted of continuing PCV would be $153 (95% PI 70-411) in 2032., Interpretation: Continuing PCV use is essential to sustain its health gains. Based on the Kenyan GDP per capita of $1445, and in comparison to other vaccines, continued PCV use at full costs is cost-effective (on the basis of the assumption that any reduction in disease will translate to a reduction in mortality). Although affordability is likely to be a concern, our findings support an expansion of the vaccine budget in Kenya., Funding: Wellcome Trust and Gavi, the Vaccine Alliance., (Copyright © 2019 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Background: In 2014 the Kenya National Immunization Technical Advisory Group (KENITAG) was asked by the Ministry of Health to provide an evidence-based recommendation on whether the seasonal influenza vaccine should be introduced into the national immunization program (NIP)., Methods: We reviewed KENITAG manuals, reports and meeting minutes generated between June 2014 and June 2016 in order to describe the process KENITAG used in arriving at that recommendation and the challenges encountered., Results: KENITAG developed a recommendation framework to identify critical, important and non-critical data elements that would guide deliberations on the subject. Literature searches were conducted in several databases and the quality of scientific articles obtained was assessed using the Critical Appraisal Skills Programme tool. There were significant gaps in knowledge on the national burden of influenza disease among key risk groups, i.e., pregnant women, individuals with co-morbidities, the elderly and health care workers. Insufficient funding and limited work force hindered KENITAG activities. In 2016 KENITAG recommended introduction of the annual seasonal influenza vaccine among children 6 to 23 months of age. However, the recommendation was contingent on implementation of a pilot study to address gaps in local data on the socio-economic impact of influenza vaccination programs, strategies for vaccine delivery, and the impact of the vaccination program on the healthcare workforce and existing immunization program. KENITAG did not recommend the influenza vaccine for any other risk group due to lack of local burden of disease data., Conclusion: Local data are a critical element in NITAG deliberations, however, where local data and in particular burden of disease data are lacking, there is need to adopt scientifically acceptable methods of utilizing findings from other countries to inform local decisions in a manner that is valid and acceptable to decision makers., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Rotavirus vaccine was introduced in Kenya immunization program in July 2014. Pre-vaccine disease burden estimates are important for assessing vaccine impact., Methods: Children with acute gastroenteritis (AGE) (≥3 loose stools and/or ≥ 1 episode of unexplained vomiting followed by loose stool within a 24-h period), hospitalized in Siaya County Referral Hospital (SCRH) from January 2010 through December 2013 were enrolled. Stool specimens were tested for rotavirus (RV) using an enzyme immunoassay (EIA). Hospitalization rates were calculated using person-years of observation (PYO) from the Health Demographic Surveillance System (HDSS) as a denominator, while adjusting for healthcare utilization at household level and proportion of stool specimen collected from patients who met the case definition at the surveillance hospital. Mortality rates were calculated using PYO as the denominator and number of deaths estimated using total deaths in the HDSS, proportion of deaths attributed to diarrhoea by verbal autopsy (VA) and percent positive for rotavirus AGE (RVAGE) hospitalizations., Results: Of 7760 all-cause hospitalizations among children < 5 years of age, 3793 (49%) were included in the analysis. Of these, 21% (805) had AGE; RV was detected in 143 (26%) of 541 stools tested. Among children < 5 years, the estimated hospitalization rates per 100,000 PYO for AGE and RVAGE were 2413 and 429, respectively. Mortality rate associated with AGE and RVAGE were 176 and 45 per 100,000 PYO, respectively., Conclusion: AGE and RVAGE caused substantial health care burden (hospitalizations and deaths) before rotavirus vaccine introduction in Kenya.

Background: The benefits of childhood vaccines are critically dependent on vaccination coverage. We used a vaccine registry (as gold standard) in Kenya to quantify errors in routine coverage methods (surveys and administrative reports), to estimate the magnitude of survivor bias, contrast coverage with timeliness and use both measures to estimate population immunity., Methods: Vaccination records of children in the Kilifi Health and Demographic Surveillance System (KHDSS), Kenya were combined with births, deaths, migration and residence data from 2010 to 17. Using inverse survival curves, we estimated up-to-date and age-appropriate vaccination coverage, calculated mean vaccination coverage in infancy as the area under the inverse survival curves, and estimated the proportion of fully immunised children (FIC). Results were compared with published coverage estimates. Risk factors for vaccination were assessed using Cox regression models., Results: We analysed data for 49,090 infants and 48,025 children aged 12-23 months in 6 birth cohorts and 6 cross-sectional surveys respectively, and found 2nd year of life surveys overestimated coverage by 2% compared to birth cohorts. Compared to mean coverage in infants, static coverage at 12 months was exaggerated by 7-8% for third doses of oral polio, pentavalent (Penta3) and pneumococcal conjugate vaccines, and by 24% for the measles vaccine. Surveys and administrative coverage also underestimated the proportion of the fully immunised child by 10-14%. For BCG, Penta3 and measles, timeliness was 23-44% higher in children born in a health facility but 20-37% lower in those who first attended during vaccine stock outs., Conclusions: Standard coverage surveys in 12-23 month old children overestimate protection by ignoring timeliness, and survivor and recall biases. Where delayed vaccination is common, up-to-date coverage will give biased estimates of population immunity. Surveys and administrative methods also underestimate FIC prevalence. Better measurement of coverage and more sophisticated analyses are required to control vaccine preventable diseases., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Although electronic health information systems (EHIS) with immunization components exist in Kenya, questions and concerns remain about their use and alignment with the Kenya Ministry of Health's (MOH) National Vaccine and Immunization Program (NVIP). This article reports on the findings of an assessment of select EHIS with immunization components in Kenya, specifically related to system design, development, and implementation., Methods: We conducted a rapid assessment of select EHIS with immunization components in Kenya from January to May 2017 to understand the design, development, implementation of the EHIS including the lessons learned from their use. We also assessed how the data elements in the EHIS compared to the data elements in the Maternal and Child Health Booklet used in the existing paper based system in Kenya., Results: The EHIS reviewed varied in purpose, content, and population covered. Only one system was built to focus specifically on immunization data. Substantial differences in system functionality and immunization-related data elements included in the EHIS were identified. None of the EHIS had all the data elements necessary to fully replace or operate independently from the standardized paper-based system for recording immunization data in Kenya., Conclusions: Overall, the findings of this assessment highlighted substantial variation in the EHIS with immunization components. The findings provide insights and lessons learned for the Kenya MOH NVIP, immunization partners, vendors of EHIS, and users of EHIS to consider as Kenya transitions from paper-based to electronic immunization information systems.

Background: Home-based records (HBRs), which take many forms, serve as an important tool for frontline health workers by providing a standardized patient history vital to making informed decisions about the need for immunization services. There are increasing concerns around HBRs with recording areas that are functionally irrelevant because records are incomplete or not up-to-date. The aim of this report was to describe HBR ownership and report on the utilization of selected recording areas in HBRs across selected study communities in Kenya., Methods: The Kenya Missed Opportunities for Vaccination Assessment utilized a mixed-methods approach that included exit interviews, using a standardized questionnaire, among a convenience sample of caregivers of children aged <24 months attending a health facility during November 2016 as well as interviews of health staff and facility administrators. In addition to the exit interview data, we analysed data obtained from a review of available HBRs from the children., Results: A total of 677 children were identified with a valid date of birth and who were aged <24 months. A HBR was in hand and reviewed for three-quarters of the children. Nearly one-third (n = 41) of those without a HBR in hand at the visit noted that they did not know the importance of bringing the document with them. Roughly two-thirds (n = 443) of caregivers noted they were asked by clinic staff to see the HBR during the clinic visit. Across the 516 reviewed HBRs, recording areas were most commonly identified for the child's demographic information (80% of HBRs) and vaccination history (82%) with information marked in >90% of records. Recording areas were less frequently available for child early eye / vision problems (61%), growth monitoring (74%) and vitamin A (76%); with information marked in 33%, 88% and 60% of records, respectively., Conclusions: Critical to the reduction of missed opportunities for vaccination, the HBR's importance must be emphasized and the document must be requested by health workers at every health encounter. Health workers must not only ensure that all children receive a HBR and counsel caregivers of its importance, but they must also ensure that all sections of the record are legibly completed to ensure continuity of care. Programmes are encouraged to periodically review and critically assess the HBR to determine whether the document's design and content areas are optimal to end user needs., Competing Interests: One author (DWB) works for a private consulting company Brown Consulting Group International, LLC his employment with this company does not alter our adherence to PLOS ONE policies on sharing data and materials.

Introduction: To achieve measles elimination, two doses of measles-containing vaccine (MCV) are provided through routine immunization services or vaccination campaigns. In May 2016, Kenya conducted a measles-rubella (MR) vaccination campaign targeting 19 million children aged 9 months-14 years, with a goal of achieving ≥95% coverage. We conducted a post-campaign cluster survey to estimate national coverage and classify coverage in Kenya's 47 counties., Methods: The stratified multi-stage cluster survey included data from 20,011 children in 8,253 households sampled using the recently revised World Health Organization coverage survey methodology (2015). Point estimates and 95% confidence intervals (95% CI) of national campaign coverage were calculated, accounting for study design. County vaccination coverage was classified as 'pass,' 'fail,' or 'intermediate,' using one-sided hypothesis tests against a 95% threshold., Results: Estimated national MR campaign coverage was 95% (95% CI: 94%-96%). Coverage differed significantly (p < 0.05) by child's school attendance, mother's education, household wealth, and other factors. In classifying coverage, 20 counties passed (≥95%), two failed (<95%), and 25 were intermediate (unable to classify either way). Reported campaign awareness among caretakers was 92%. After the 2016 MR campaign, an estimated 93% (95% CI: 92%-94%) of children aged 9 months to 14 years had received ≥2 MCV doses; 6% (95% CI: 6%-7%) had 1 MCV dose; and 0.7% (95% CI: 0.6%-0.9%) remained unvaccinated., Conclusions: Kenya reached the MR campaign target of 95% vaccination coverage, representing a substantial achievement towards increasing population immunity. High campaign awareness reflected the comprehensive social mobilization strategy implemented in Kenya and supports the importance of including strong communications platforms in future vaccination campaigns. In counties with sub-optimal MR campaign coverage, further efforts are needed to increase MCV coverage to achieve the national goal of measles elimination by 2020., Competing Interests: The authors have declared that no competing interests exist.

Introduction: A Measles rubella campaign that targeted 9 months to 14 year old children was conducted in all the 47 counties in Kenya between 16th and 24th of May 2016. Micro-planning using an android phone-based app was undertaken to map out the target population and logistics in all the counties 4 weeks to the campaign implementation instead of 6 months as per the WHO recommendation. The outcomes of the micro-planning exercise were a detailed micro-plan that served as a guide in ensuring that every eligible individual in the population was vaccinated with potent vaccine. A national Trainer of Trainers training was done to equip key officers with new knowledge and skills in developing micro-plans at all levels. The micro planning was done using a mobile phone app, the doforms that enabled data to be transmitted real time to the national level. The objective of the study was to establish whether use of mobile phone app would contribute to quality of sub national micro plans that can be used for national level planning and implementation of the campaign., Methods: There were 9 data collection forms but only forms 1-7 were to be uploaded onto the app. Forms 8A and 9A were to be filled but were to remain at the implementation level for use intra campaign. The forms were coded; Form 1A&B, 2A, 3A, 4A, 5A, 6A, 7A, 8A and 9A The Village form (form 1A&B) captured information by household which included village names, name of head of household, cell phone contact of head of household, number of children aged 9 months to 14years in the household, possible barriers to reaching the children, appropriate vaccination strategy based on barriers identified and estimated or proposed number of teams and type. This was the main form and from this every other form picked the population figures to estimate other supplies and logistics. On advocacy, communication and social mobilization the information collected included mobile network coverage, public amenities such as churches, mosques and key partners at the local level. On human resource and cold chain supplies the information collected included number of health facilities by type, number of health workers by cadre in facilities within the village, number of vaccine carriers and icepacks by size, refrigerators and freezers. All these forms were to be uploaded onto the phone app. except form 8A, the individual team plan, which was to be used during implementation at the local level. Android phone application, doforms, was used to capture data. Training on micro planning, data entry and doforms app was conducted at National, County, Sub-county and ward levels using standardized guidelines. An interactive case study was used in all the trainings to facilitate understanding. The App was also available on Laptops through its provided web-application. The app allowed multiple users to log in concurrently. Feedback on all the variables were obtained from the team at the Ward level. The ward level team included education officers or teachers, village elders, community health workers and other community stakeholders. Only the Ward level was allowed to collect information on paper and that information was subsequently transferred to the phone-based app, doforms, by health information officers. The national, county and sub county were able to access their data from the app using a password provided by the administrator., Results: Real time data was received from 46 of 47 counties. One county (Marsabit) did not participate in the micro plan process. Over 97% (283/290) of the sub counties responded and shared various information via the app. Different data forms had different completion rates. There was 100% completion rate for the data on villages and target population. Much valuable information was shared but there was no time for the national and county level to interrogate and harmonize for proper implementation. The information captured during the campaign can be used for routine immunization and other community based interventions. Electronic data collection not only provided the number of children but provided the locations also where these children could be found., Conclusion: Despite the limitations of time to harmonize the micro plans with the national plan, the micro planning process was a great success with 46/47 counties responding through the mobile phone app. Not only did it provide the numbers of the target children, it further provided the places where these children could be found. There was timely data transfer, data integrity, tracking, real time data visualization reporting and analysis. The app enabled real time feedback to national focal point by data entry clerks as well as enabling trouble shooting by the administrator. This ensured campaign planning was done from the lowest level to the national level.

Background: The epidemiology of non-Typhi Salmonella (NTS) bacteremia in Africa will likely evolve as potential co-factors, such as HIV, malaria, and urbanization, also change., Methods: As part of population-based surveillance among 55,000 persons in malaria-endemic, rural and malaria-nonendemic, urban Kenya from 2006-2009, blood cultures were obtained from patients presenting to referral clinics with fever ≥38.0°C or severe acute respiratory infection. Incidence rates were adjusted based on persons with compatible illnesses, but whose blood was not cultured., Results: NTS accounted for 60/155 (39%) of blood culture isolates in the rural and 7/230 (3%) in the urban sites. The adjusted incidence in the rural site was 568/100,000 person-years, and the urban site was 51/100,000 person-years. In both sites, the incidence was highest in children <5 years old. The NTS-to-typhoid bacteremia ratio in the rural site was 4.6 and in the urban site was 0.05. S. Typhimurium represented >85% of blood NTS isolates in both sites, but only 21% (urban) and 64% (rural) of stool NTS isolates. Overall, 76% of S. Typhimurium blood isolates were multi-drug resistant, most of which had an identical profile in Pulse Field Gel Electrophoresis. In the rural site, the incidence of NTS bacteremia increased during the study period, concomitant with rising malaria prevalence (monthly correlation of malaria positive blood smears and NTS bacteremia cases, Spearman's correlation, p = 0.018 for children, p = 0.16 adults). In the rural site, 80% of adults with NTS bacteremia were HIV-infected. Six of 7 deaths within 90 days of NTS bacteremia had HIV/AIDS as the primary cause of death assigned on verbal autopsy., Conclusions: NTS caused the majority of bacteremias in rural Kenya, but typhoid predominated in urban Kenya, which most likely reflects differences in malaria endemicity. Control measures for malaria, as well as HIV, will likely decrease the burden of NTS bacteremia in Africa.