Search

BACKGROUND: In Spring 2021, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.7 (Alpha) became the predominant variant in the United States. Research suggests that Alpha has increased transmissibility compared with non-Alpha lineages. We estimated household secondary infection risk (SIR), assessed characteristics associated with transmission, and compared symptoms of persons with Alpha and non-Alpha infections. METHODS: We followed households with SARS-CoV-2 infection for 2 weeks in San Diego County and metropolitan Denver, January to April 2021. We collected epidemiologic information and biospecimens for serology, reverse transcription-polymerase chain reaction (RT-PCR), and whole-genome sequencing. We stratified SIR and symptoms by lineage and identified characteristics associated with transmission using generalized estimating equations. RESULTS: We investigated 127 households with 322 household contacts; 72 households (56.7%) had member(s) with secondary infections. SIRs were not significantly higher for Alpha (61.0% [95% confidence interval, 52.4-69.0%]) than non-Alpha (55.6% [44.7-65.9%], P = .49). In households with Alpha, persons who identified as Asian or Hispanic/Latino had significantly higher SIRs than those who identified as White (P = .01 and .03, respectively). Close contact (eg, kissing, hugging) with primary cases was associated with increased transmission for all lineages. Persons with Alpha infection were more likely to report constitutional symptoms than persons with non-Alpha (86.9% vs 76.8%, P = .05). CONCLUSIONS: Household SIRs were similar for Alpha and non-Alpha. Comparable SIRs may be due to saturation of transmission risk in households due to extensive close contact, or true lack of difference in transmission rates. Avoiding close contact within households may reduce SARS-CoV-2 transmission for all lineages among household members.

BACKGROUND: COVID-19 vaccination reduces SARS-CoV-2 infection and transmission. However, evidence is emerging on the degree of protection across variants and in high-transmission settings. To better understand the protection afforded by vaccination specifically in a high-transmission setting, we examined household transmission of SARS-CoV-2 during a period of high community incidence with predominant SARS-CoV-2 B.1.1.7 (Alpha) variant, among vaccinated and unvaccinated contacts. METHODS: We conducted a household transmission investigation in San Diego County, California, and Denver, Colorado, during January-April 2021. Households were enrolled if they had at least one person with documented SARS-CoV-2 infection. We collected nasopharyngeal swabs, blood, demographic information, and vaccination history from all consenting household members. We compared infection risks (IRs), RT-PCR cycle threshold values, SARS-CoV-2 culture results, and antibody statuses among vaccinated and unvaccinated household contacts. RESULTS: We enrolled 493 individuals from 138 households. The SARS-CoV-2 variant was identified from 121/138 households (88%). The most common variants were Alpha (75/121, 62%) and Epsilon (19/121, 16%). There were no households with discordant lineages among household members. One fully vaccinated secondary case was symptomatic (13%); the other 5 were asymptomatic (87%). Among unvaccinated secondary cases, 105/108 (97%) were symptomatic. Among 127 households with a single primary case, the IR for household contacts was 45% (146/322; 95% Confidence Interval [CI] 40-51%). The observed IR was higher in unvaccinated (130/257, 49%, 95% CI 45-57%) than fully vaccinated contacts (6/26, 23%, 95% CI 11-42%). A lower proportion of households with a fully vaccinated primary case had secondary cases (1/5, 20%) than households with an unvaccinated primary case (66/108, 62%). CONCLUSIONS: Although SARS-CoV-2 infections in vaccinated household contacts were reported in this high transmission setting, full vaccination protected against SARS-CoV-2 infection. These findings further support the protective effect of COVID-19 vaccination and highlight the need for ongoing vaccination among eligible persons.

OBJECTIVE: To assess the household secondary infection risk (SIR) of B.1.1.7 (Alpha) and non-Alpha lineages of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children. STUDY DESIGN: During January to April 2021, we prospectively followed households with a SARS-CoV-2 infection. We collected questionnaires, serial nasopharyngeal swabs for reverse transcription polymerase chain reaction testing and whole genome sequencing, and serial blood samples for serology testing. We calculated SIRs by primary case age (pediatric vs adult), household contact age, and viral lineage. We evaluated risk factors associated with transmission and described symptom profiles among children. RESULTS: Among 36 households with pediatric primary cases, 21 (58%) had secondary infections. Among 91 households with adult primary cases, 51 (56%) had secondary infections. SIRs among pediatric and adult primary cases were 45% and 54%, respectively (OR, 0.79; 95% CI, 0.41-1.54). SIRs among pediatric primary cases with Alpha and non-Alpha lineage were 55% and 46%, respectively (OR, 1.52; 95% CI, 0.51-4.53). SIRs among pediatric and adult household contacts were 55% and 49%, respectively (OR, 1.01; 95% CI, 0.68-1.50). Among pediatric contacts, no significant differences in the odds of acquiring infection by demographic or household characteristics were observed. CONCLUSIONS: Household transmission of SARS-CoV-2 from children and adult primary cases to household members was frequent. The risk of secondary infection was similar among child and adult household contacts. Among children, household transmission of SARS-CoV-2 and the risk of secondary infection was not influenced by lineage. Continued mitigation strategies (eg, masking, physical distancing, vaccination) are needed to protect at-risk groups regardless of virus lineage circulating in communities.

Since identification of SARS-CoV-2 and the ensuing pandemic, epidemiologic studies have shown that COVID-19 outcomes are less severe among children than adults (1-8). Conclusions drawn from published studies on COVID-19 [...]

Objectives: The workplace is an important setting for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) exposure and transmission. Using data from a large case–control study in Colorado during 2021 and 2022, we aimed to evaluate working outside the home and SARS‐CoV‐2 infection, the racial and ethnic distribution of workers in occupations associated with infection, and workplace face mask use. Methods: Cases were Colorado adults with a positive SARS‐CoV‐2 test by reverse transcription‐polymerase chain reaction (RT‐PCR) reported to Colorado's COVID‐19 surveillance system selected from surveillance data ≤12 days after their specimen collection date. Control participants were randomly selected adult Coloradans with a RT‐PCR‐confirmed negative SARS‐CoV‐2 test result reported to the same surveillance system. Results: Working outside the home was associated with infection (odds ratio [OR] = 1.46, 95% confidence interval [CI]: 1.39–1.54). Among participants working outside the home, "Food Preparation and Serving Related" (aOR = 2.35, 95% CI: 1.80–3.06), "Transportation and Material Moving" (aOR = 2.09, 95% CI: 1.62–2.69), "Construction and Extraction" (aOR = 1.88, 95% CI: 1.36–2.59), "Protective Service" (aOR = 1.60, 95% CI: 1.15–2.24), and "Sales and Related" (aOR = 1.44, 95% CI: 1.22–1.69) were occupational categories most strongly associated with infection. American Indian/Alaskan Native, Black, and Hispanic/Latino participants were more likely than others to work in occupational categories with the highest odds of infection (p < 0.05). Cases were less likely than controls to report always wearing a mask (31.9% vs. 41.5%) and wearing a KN95/N95/KF94 mask (16.8% vs. 27.2%) at work. Conclusions: These findings emphasize the importance of occupation and workplace mask use in the COVID‐19 pandemic and its disproportionate racial/ethnic impact on workers. [ABSTRACT FROM AUTHOR]

Objectives. We sought to determine whether monitoring rapid influenza laboratory tests improved the influenza-like illness surveillance already in place in New Mexico. Methods. For the past 3 influenza seasons, the New Mexico Department of Health examined influenza-like illness visits and positive rapid influenza test results. Results. The proportion of positive rapid influenza test results started to rise earlier than did the percentage of clinical visits because of influenza-like illness in each of the past 3 influenza seasons: 5 weeks earlier during the 2004-2005 season; 3 weeks earlier in 2005-2006; and 2 weeks earlier in 2006-2007. In addition, rapid influenza tests showed a spike in influenza B activity late in the 2005- 2006 season that influenza-like illness syndrome surveillance did not. Conclusions. Laboratory-based rapid influenza test surveillance required relatively few resources to implement and offered a sensitive mechanism to detect the onset of influenza activity while allowing for the distinction of influenza types. (Am J Public Health. 2009;99:S372-S377. doi: 10.2105/AJPH.2007.125450)

While risk of fomite transmission of SARS-CoV-2 is considered low, there is limited environmental data within households. This January—April 2021 investigation describes frequency and types of surfaces positive for SARS-CoV-2 by real-time reverse transcription polymerase chain reaction (RT-PCR) among residences with ≥1 SARS-CoV-2 infection, and associations of household characteristics with surface RT-PCR and viable virus positivity. Of 1232 samples from 124 households, 27.8% (n = 342) were RT-PCR positive with nightstands (44.1%) and pillows (40.9%) most frequently positive. SARS-CoV-2 lineage, documented household transmission, greater number of infected persons, shorter interval between illness onset and sampling, total household symptoms, proportion of infected persons ≤12 years old, and persons exhibiting upper respiratory symptoms or diarrhea were associated with more positive surfaces. Viable virus was isolated from 0.2% (n = 3 samples from one household) of all samples. This investigation suggests that while SARS-CoV-2 on surfaces is common, fomite transmission risk in households is low. [ABSTRACT FROM AUTHOR]

A study is conducted to evaluate the efficacy of prevention guidelines in helping reduce the incidence of invasive Group B Streptococcal disease in the U.S. from 1999 to 2005. Results indicate a reduction in mortality among children from invasive Group B Streptococcal disease while on the other hand it had no effect on adults with the same disease.

Feverish children with liver and spleen lesions may be diagnosed with cat scratch disease. Researchers used imaging diagnostics in two cases of fever. A 5-year-old girl had persistently high fever for more than 3 weeks and abdominal pain. Biopsy confirmed acute and chronic inflammation of liver tissue after small liver lesions appeared in her ultrasound and CT scans. Further tissue analysis identified Rochalimaea henselae, the agent thought to cause cat scratch disease. The second child, a 7-year-old boy, had fever of 104 degrees for six weeks. Liver and spleen lesions appeared on the imaging screens and cat scratch disease was diagnosed following tissue analysis. Both children had interacted with new kittens in their homes and were thought to have unusual forms of cat scratch disease., ABSTRACT. Objective. To report the clinical course, imaging findings, and method of diagnosis of two patients with systemic manifestations of cat scratch disease, presenting with fever of unknown origin. Design. Case study. Patients. Two children with fever of unknown origin who had multiple lesions in the liver and spleen, shown on ultrasound, computed tomography, and magnetic resonance imaging. Initial diagnoses were Kawasaki disease (case 1) and metastatic neuroblastoma (case 2). Results. Biopsy material showed granulomatous hepatitis in both patients. The diagnoses were confirmed by positive assays for Rochalimaea henselae, currently thought to be the causative agent of cat scratch disease. Conclusion. Cat scratch disease presenting as fever of unknown origin is now well described and can be more readily diagnosed because of the availability of new serologic assays, as well as polymerase chain reaction assays for R henselae DNA in tissue specimens., Cat scratch disease is a well-recognized, benign, self-limited cause of fever and regional adenopathy in children who are immunocompetent, after a scratch from a kitten. Less commonly, patients may present [...]

Background: Sequential mixed-mode surveys using both web-based surveys and telephone interviews are increasingly being used in observational studies and have been shown to have many benefits; however, the application of this survey design has not been evaluated in the context of epidemiological case-control studies., Objective: In this paper, we discuss the challenges, benefits, and limitations of using a sequential mixed-mode survey design for a case-control study assessing risk factors during the COVID-19 pandemic., Methods: Colorado adults testing positive for SARS-CoV-2 were randomly selected and matched to those with a negative SARS-CoV-2 test result from March to April 2021. Participants were first contacted by SMS text message to complete a self-administered web-based survey asking about community exposures and behaviors. Those who did not respond were contacted for a telephone interview. We evaluated the representativeness of survey participants to sample populations and compared sociodemographic characteristics, participant responses, and time and resource requirements by survey mode using descriptive statistics and logistic regression models., Results: Of enrolled case and control participants, most were interviewed by telephone (308/537, 57.4% and 342/648, 52.8%, respectively), with overall enrollment more than doubling after interviewers called nonresponders. Participants identifying as female or White non-Hispanic, residing in urban areas, and not working outside the home were more likely to complete the web-based survey. Telephone participants were more likely than web-based participants to be aged 18-39 years or 60 years and older and reside in areas with lower levels of education, more linguistic isolation, lower income, and more people of color. While there were statistically significant sociodemographic differences noted between web-based and telephone case and control participants and their respective sample pools, participants were more similar to sample pools when web-based and telephone responses were combined. Web-based participants were less likely to report close contact with an individual with COVID-19 (odds ratio [OR] 0.70, 95% CI 0.53-0.94) but more likely to report community exposures, including visiting a grocery store or retail shop (OR 1.55, 95% CI 1.13-2.12), restaurant or cafe or coffee shop (OR 1.52, 95% CI 1.20-1.92), attending a gathering (OR 1.69, 95% CI 1.34-2.15), or sport or sporting event (OR 1.05, 95% CI 1.05-1.88). The web-based survey required an average of 0.03 (SD 0) person-hours per enrolled participant and US $920 in resources, whereas the telephone interview required an average of 5.11 person-hours per enrolled participant and US $70,000 in interviewer wages., Conclusions: While we still encountered control recruitment challenges noted in other observational studies, the sequential mixed-mode design was an efficient method for recruiting a more representative group of participants for a case-control study with limited impact on data quality and should be considered during public health emergencies when timely and accurate exposure information is needed to inform control measures., (©Amanda D Tran, Alice E White, Michelle R Torok, Rachel H Jervis, Bernadette A Albanese, Elaine J Scallan Walter. Originally published in JMIR Formative Research (https://formative.jmir.org), 27.05.2024.)

Importance: As self-collected home antigen tests become widely available, a better understanding of their performance during the course of SARS-CoV-2 infection is needed., Objective: To evaluate the diagnostic performance of home antigen tests compared with reverse transcription-polymerase chain reaction (RT-PCR) and viral culture by days from illness onset, as well as user acceptability., Design, Setting, and Participants: This prospective cohort study was conducted from January to May 2021 in San Diego County, California, and metropolitan Denver, Colorado. The convenience sample included adults and children with RT-PCR-confirmed infection who used self-collected home antigen tests for 15 days and underwent at least 1 nasopharyngeal swab for RT-PCR, viral culture, and sequencing., Exposures: SARS-CoV-2 infection., Main Outcomes and Measures: The primary outcome was the daily sensitivity of home antigen tests to detect RT-PCR-confirmed cases. Secondary outcomes included the daily percentage of antigen test, RT-PCR, and viral culture results that were positive, and antigen test sensitivity compared with same-day RT-PCR and cultures. Antigen test use errors and acceptability were assessed for a subset of participants., Results: This study enrolled 225 persons with RT-PCR-confirmed infection (median [range] age, 29 [1-83] years; 117 female participants [52%]; 10 [4%] Asian, 6 [3%] Black or African American, 50 [22%] Hispanic or Latino, 3 [1%] Native Hawaiian or Other Pacific Islander, 145 [64%] White, and 11 [5%] multiracial individuals) who completed 3044 antigen tests and 642 nasopharyngeal swabs. Antigen test sensitivity was 50% (95% CI, 45%-55%) during the infectious period, 64% (95% CI, 56%-70%) compared with same-day RT-PCR, and 84% (95% CI, 75%-90%) compared with same-day cultures. Antigen test sensitivity peaked 4 days after illness onset at 77% (95% CI, 69%-83%). Antigen test sensitivity improved with a second antigen test 1 to 2 days later, particularly early in the infection. Six days after illness onset, antigen test result positivity was 61% (95% CI, 53%-68%). Almost all (216 [96%]) surveyed individuals reported that they would be more likely to get tested for SARS-CoV-2 infection if home antigen tests were available over the counter., Conclusions and Relevance: The results of this cohort study of home antigen tests suggest that sensitivity for SARS-CoV-2 was moderate compared with RT-PCR and high compared with viral culture. The results also suggest that symptomatic individuals with an initial negative home antigen test result for SARS-CoV-2 infection should test again 1 to 2 days later because test sensitivity peaked several days after illness onset and improved with repeated testing.

In January 2017, the Colorado Department of Public Health and Environment (CDPHE) identified four epidemiologically linked cases of mumps among persons from a Marshallese community who were members of the same church in the Denver metropolitan area. During 2016-2017, sizable outbreaks of mumps reported in Arkansas, Hawaii, and Washington also affected the Marshallese population (1). CDPHE, the Tri-County Health Department (TCHD), and Denver Public Health collaborated to conduct an outbreak investigation during January-March 2017 using active and passive surveillance that identified 17 confirmed and 30 probable cases. Public health actions included conducting measles-mumps-rubella (MMR) vaccination clinics at local Marshallese churches; these resulted in the vaccination of 126 persons with ≥1 doses of MMR vaccine. Implementation of active surveillance and support from local Marshallese church leaders in promoting vaccination programs likely contributed to interruption of the outbreak., Competing Interests: All authors have completed and submitted the ICMJE form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.

During July 2016-January 2017, two unrelated measles cases were identified in the Denver, Colorado area after patients traveled to countries with endemic measles transmission. Each case resulted in multiple exposures at health care facilities and public venues, and activated an immediate and complex response by local and state public health agencies, with activities led by the Tri-County Health Department (TCHD), which serves Adams, Arapahoe, and Douglas counties. To track the economic burden associated with investigating and responding to single measles cases, personnel hours and supply costs incurred during each investigation were tracked prospectively. No secondary cases of measles were identified in either investigation. Postexposure prophylaxis (PEP) was administered to 31 contacts involving the first case; no contacts of the second case were eligible for PEP because of a delay in diagnosing measles disease. Public health costs of disease investigation in the first and second case were estimated at $49,769 and $18,423, respectively. Single measles cases prompted coordinated public health action and were costly and resource-intensive for local public health agencies.