Search

BACKGROUND Measles is a highly infectious illness requiring herd immunity of 95% to interrupt transmission. China has not reached elimination goals despite high vaccination coverage. We estimated the population susceptibility against measles in Tianjin, China and to tailor awareness raising activities in the measles elimination plan. METHODS Age-specific measles seroprevalence was evaluated by Enzyme-Linked Immunosorbent Assay (ELISA) on 12,164 individual aged 0-44 years in 2009-2018. Measles IgG avidity testing was performed to confirm the relationship of the waning immunity after vaccination and secondary vaccination failures (SVF) on 324 confirmed measles cases in 2013-2018. RESULTS 11,108 samples (91.32%) tested positive for measles IgG, 239 (1.96%) tested as equivocal and 817 (6.72%) were negative. The age distribution of measles cases in Tianjin followed a U-shaped curve and was highest for those at

Although global progress in measles control has been realized, achieving elimination has proven difficult in many regions of the world. China has adopted a goal of measles elimination but recent outbreaks predominantly affecting children8 months who are ineligible for vaccination and incompletely protected by maternal antibodies has impeded progress. We assess the cost-effectiveness of adding an initial measles vaccine dose in China to earlier than the currently recommended 8 months of age.We conducted a cost-utility analysis comparing the costs and health benefits associated with adding a measles vaccine dose to the routine schedule at 4, 5, 6 or 7 months compared to the current recommendation for the first dose at age 8 months. A decision analytic model was developed in Microsoft Excel, including five non-severe and two fatal health outcomes associated with measles infection. Model parameters were informed by the literature and surveillance data. Future costs and health benefits were discounted at 3%. Primary outcomes included costs, Quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) over a lifetime time horizon.Lowering the recommended age for initiating the measles vaccination series to address susceptibility in children8 months provided incremental health gains compared to minimal costs at the individual-level. The ICER was most favorable ($232.70 per QALY gain) for administering an initial dose at 4 months of age due to fewer incremental program costs when shifting measles administration to an immunization visit already established under the Chinese vaccination program.We found potential beneficial health gains at a minimum cost associated with adding an earlier measles dose8 months of age in China. Further investigation about disease transmission dynamics is required to more fully assess the tradeoffs of administering measles at a younger age to infants in China.

Background Many measles cases in Tianjin, China, occur in infants whose mothers were born after widespread vaccination programs. We assessed age-specific decreases in maternal measles antibodies in infants and examined maternal and infant characteristics in relation to infant antibody titers. Methods Infant and mother dyads were enrolled from a sample of immunization clinics in all Tianjin districts. Participants' antibody titers were measured from dried blood spots. A multivariable log-linear model regressed infant antibody titers onto infant and mother characteristics. Results Among 551 infants aged ≤8 months, protective levels of measles antibodies were observed in infants whose mothers had measles titers ≥800 IU/mL (mean antibody titer, 542.5 IU/mL) or 400 to

Despite increasing global measles vaccination coverage, progress toward measles elimination has slowed in recent years. In China, children receive a measles-containing vaccine (MCV) at 8 months, 18–24 months, and some urban areas offer a third dose at age 4–6 years. However, substantial measles cases in Tianjin, China, occur among individuals who have received multiple MCV doses. This study describes the vaccination history of measles cases 8 months – 19 years old. Data came from measles cases in Tianjin’s reportable disease surveillance system (2009–2013), and from a case control study (2011–2015). Twenty-nine percent of those in the surveillance dataset and 54.4% of those in the case series received at least one dose of MCV. The minimum and median time-to-diagnosis since vaccination revealed an increase in time since vaccination for incremental doses. Considerable measles cases in Tianjin occur in vaccinated children, and further research is needed to understand the reasons for vaccine failure.

Background: Measles incidence in China has declined over the last decade and elimination is targeted by 2020. Despite increases in routine immunization services and supplementary immunization activities (SIAs) periodic outbreaks continue to occur. In this paper we examine measles epidemiology during 2005-2014 in Tianjin China. Methods: Measles case data were extracted from a web-based communicable disease surveillance system. We examined the socio-demographic characteristics of measles case patients including age sex urbanicity residency status and vaccination history. Demographic characteristics of cases were compared with the general population. Results: From January 1 2005 to December 31 2014 12466 measles cases in Tianjin were reported. Among the cases 7179 (57.6%) were male and 5287 (42.4%) were female. Over time more cases occurred in adults and for the 2711 cases in 2014 the majority were either infants

Infants aged8 months are ineligible for measles vaccination in China but represent a disproportionate number of cases. We examined the risk factors for measles among infants in Tianjin, China.Case-control study.Cases were enrolled from a surveillance system, and IgG-negative controls were sampled from registries at immunization clinics. A logistic regression model assessed for risk factors.Among 82 cases and 485 controls, exposure to a municipal hospital (OR [odds ratio]: 5.21; 95% confidence interval [CI]: 1.19-22.82) or a specialty hospital (OR: 13.22; 95% CI: 6.13-28.51) was associated with the disease, whereas visiting a township or district hospitals was not associated with increased odds of measles.Hospitals were an important focal point of measles transmission for infants. Hospitals, particularly higher-level municipal and specialty hospitals, should enforce infection control programs to separate infants with highly communicable diseases to prevent transmission.

SUMMARYActive symptom surveillance was applied to three selected communities ( 160 147 persons) in Tianjin from 2010 to 2012. We examined 1089 individuals showing pertussis-like symptoms, of which 1022 nasopharyngeal specimens were tested for pertussis by polymerase chain reaction and 802 sera for anti-pertussis toxin antibodies. Of the total cases tested, 113 were confirmed, and their demographic, clinical, and vaccination-related data were collected. The annual incidence was 23·52 cases/100 000 persons among communities, which was 16·22 times that obtained via hospital reports for the same period (P< 0·001). The actual incidence in the 15–69 years age group was most significantly underestimated by hospitals, given that it was 43·08 times that of the reported hospital rate. Among the cases aged

Recent advance in the direct-acting antivirals (DAAs) offers the potentials to eradicate hepatitis C virus (HCV) worldwide and makes universal screening more urgent. A point-of-care (POC) oral anti-HCV assay, the Fortune assay, was developed and its performance was evaluated. Individuals with or without HCV infection were recruited in three Centers. Paired oral and serum samples were tested using the Fortune and InTec anti-HCV assays. The Kehua serum anti-HCV assay served as a supplemental test to verify the discordant results. Some oral samples were also tested using the OraQuick anti-HCV assay. Furthermore, the Fortune assay results were compared with the documented RNA results. Sensitivity, specificity, and accuracy of the Fortune assay was 93.11%, 98.48%, and 96.58%, respectively (n = 1,022). Consistency between the Fortune and OraQuick assays was 96.35% (264/274); the Fortune assay detected additional 8 positive oral samples missed by the OraQuick assay. The Fortune assay demonstrated a 97.46% (115/118) positivity among the viremic patients. Furthermore, its sensitivity was HCV genotype independent. In conclusion, the Fortune assay was highly specific and accurate. It had comparable sensitivity as the serum assays for the diagnosis of active HCV infection. It provides a completely non-invasive and reliable tool for HCV screening in the DAA era.

Background Measles is a highly infectious illness requiring herd immunity of 95% to interrupt transmission. Measles is targeted for elimination in China, which has not reached elimination goals despite high vaccination coverage. We developed a population profile of measles immunity among residents aged 0–49 years in Tianjin, China. Methods Participants were either from community population registers or community immunization records. Measles IgG antibody status was assessed using dried blood spots. We examined the association between measles IgG antibody status and independent variables including urbanicity, sex, vaccination, measles history, and age. Results 2818 people were enrolled. The proportion measles IgG negative increased from 50.7% for infants aged 1 month to 98.3% for those aged 7 months. After 8 months, the age of vaccination eligibility, the proportion of infants and children measles IgG negative decreased. Overall, 7.8% of participants 9 months of age or older lacked measles immunity including over 10% of those 20–39 years. Age and vaccination status were significantly associated with measles IgG status in the multivariable model. The odds of positive IgG status were 0.337 times as high for unvaccinated compared to vaccinated (95% CI: 0.217, 0.524). Conclusions The proportion of persons in Tianjin, China immune to measles was lower than herd immunity threshold with less than 90% of people aged 20–39 years demonstrating protection. Immunization programs in Tianjin have been successful in vaccinating younger age groups although high immunization coverage in infants and children alone would not provide protective herd immunity, given the large proportion of non-immune adults.

Summary Objectives China has repeatedly used supplemental immunization activities (SIAs) to work towards measles elimination, but it is unknown if the SIAs are reaching non-locals – migrants from rural to urban areas. This study characterized temporal trends in measles incidence by local and non-local residency and evaluated the impact of SIAs on measles incidence in Tianjin, China. Methods Daily measles case-counts were tabulated separately by residency. These two datasets were combined so that each day had two observations. Poisson regression was conducted using generalized estimating equations with an exchangeable working correlation structure to estimate rate ratios (RRs). Results There were 12465 measles cases in Tianjin over the 10-year period. The rate of measles was higher in non-locals than locals before the 2008 SIA (RR 3.60, 95% confidence interval (CI) 3.27–3.96), but this attenuated to a RR of 1.22 between the 2008 and 2010 SIAs (95% CI 1.02–1.45). Following the 2010 SIA, non-locals had a lower rate of measles (RR 0.78, 95% CI 0.69–0.87). Conclusions The disparity in measles incidence between locals and non-locals was reduced following two SIAs. Sustained public health interventions will be needed to maintain low measles incidence among non-locals given the ongoing migration of people throughout China.

The aim of this study is to characterize the sera-epidemiology of pertussis immunity levels among community populations and to identify the underlying factors. Moreover, our study will help resolve new issues encountered during the control and prevention of pertussis reemergence.The anti-pertussis antibody levels among community populations were examined using enzyme linked immunosorbent assays (ELISA) over three years. Comparative studies were carried out to assess the efficacy of different types of vaccines. Meanwhile, the duration of protection provided by DTaP within the under-7 age group was subjected to further analysis.The average positive rate for anti-pertussis antibody was 49.15% across all community populations, among which the 4-12 age group showed a rate substantially lower than those of other groups (P0.001). There was no statistically significant difference in anti-pertussis antibody levels (P=0.977) between people receiving three and four doses of the vaccine. The surveillance results showed that the positive antibody response rate elicited by component pertussis combo (DTcP) vaccines (84.44%) was strikingly higher than that elicited by acellular pertussis combo (DTaP) vaccines (37.22%, P0.001). More specifically, when given 4 doses of DTcP vaccines, 66.67% of the people showed positive anti-pertussis toxin (PT) antibody levels, which was higher than the ratio of 9.87% (P0.001) in the case of DTaP vaccines. The positive anti-pertussis antibody levels peaked at 73% within the first five months following vaccination and then gradually decreased to below 20% in four years. The positive rate was inversely correlated with the length of time after vaccination (r=-0.929, P=0.003).The anti-pertussis antibody levels were not only relatively low among community populations, but also dropped excessively rapidly among vaccinated populations. Natural infection is an important contributor to the high pertussis immunity levels seen in adolescents and adults. The efficacy of DTaP remains to be improved.

Hepatitis A immunization strategies were carried out in 2001 in Tianjin. We wanted to evaluate the effectiveness of the strategies related to hepatitis A control programs and to provide the basis for further modification of the strategies.Descriptive epidemiology study was used to analyze the hepatitis A epidemic situation in 2000-2011 in Tianjin and to evaluate the disease reporting system. Hepatitis A vaccine coverage of target population and serum epidemiological study were carried out in 1999, 2005 and 2010 to check on the hepatitis A antibody levels so as to evaluate the immuno-barrier condition in the normal population. Cox-Stuart test was used to analyze the epidemic trend of hepatitis A and other intestinal infectious diseases in Tianjin.The incidence rate of hepatitis A decreased from 2.89/100 000 in 2000 to 0.12/100 000 in 2011, and the percentage of hepatitis A in all types of viral hepatitis decreased from 8.02% in 2000 to 0.48% in 2011 in Tianjin. The positive rates of hepatitis A antibody also increased in the residents.The hepatitis A vaccination program was successful in the programs on prevention and control of hepatitis A in Tianjin, China.

Background Control groups in previous case-control studies of vaccine-preventable diseases have included people immune to disease. This study examines risk factors for measles acquisition among adults 20 to 49 years of age in Tianjin, China, and compares findings using measles IgG antibody-negative controls to all controls, both IgG-negative and IgG-positive. Methods Measles cases were sampled from a disease registry, and controls were enrolled from community registries in Tianjin, China, 2011–2015. Through a best subsets selection procedure, we compared which variables were selected at different model sizes when using IgG-negative controls or all controls. We entered risk factors for measles in two separate logistic regression models: one with measles IgG-negative controls and the other with all controls. Results The study included 384 measles cases and 1,596 community controls (194 IgG-negative). Visiting a hospital was an important risk factor. For specialty hospitals, the odds ratio (OR) was 4.53 (95% confidence interval (CI): 1.28, 16.03) using IgG-negative controls, and OR = 5.27 (95% CI: 2.73, 10.18) using all controls. Variables, such as age or length of time in Tianjin, were differentially selected depending on the control group. Individuals living in Tianjin ≤3 years had 2.87 (95% CI: 1.46, 5.66) times greater odds of measles case status compared to all controls, but this relationship was not apparent for IgG-negative controls. Conclusions We recommend that case-control studies examining risk factors for infectious diseases, particularly in the context of transmission dynamics, consider antibody-negative controls as the gold standard.

Background: Measles is a highly infectious disease, and timely administration of two doses of vaccine can ensure adequate protection against measles for all ages in a population. This study aims to estimate the proportion of children aged 8 months to 6 years vaccinated on time with measles-containing vaccines (MCV) and vaccinated during the 2008 and 2010 measles supplementary immunization activities. This study also characterizes differences in mean age at vaccination and vaccination timeliness by demographic characteristics, and describes maternal knowledge of measles vaccination. Methods: Immunization records were selected from a convenience sample of immunization clinics in Tianjin, China. From the records, overall vaccination coverage and timely vaccination coverage were calculated for different demographic groups. Mothers were also interviewed at these clinics to ascertain their knowledge of measles vaccination. Results: Within the 329 immunization clinic records, child’s birth year and district of residence were found to be significant predictors of different measures of vaccine timeliness. Children born in 2009 had a lower age at MCV dose 2 administration (17.96 months) than children born in 2005 (22.00 months). Children living in Hebei, a district in the urban center of Tianjin were less likely to be vaccinated late than children living in districts further from the urban core of Tianjin. From the 31 interviews with mothers, most women believed that timely vaccination was very important and more than one dose was very necessary; most did not know whether their child needed another dose. Conclusions: When reviewing MCV coverage in China, most studies do not consider timeliness. However, this study shows that overall vaccination coverage can greatly overestimate vaccination coverage within certain segments of the population, such as young infants.