School knowledge of infectious diseases in schools: conducting surveillance and on-demand, symptomatic respiratory viral testing in a large pre-kindergarten-12th grade school district.

Background: Limited data about acute respiratory illness (ARI) and respiratory virus circulation are available in congregate community settings, specifically schools. To better characterize the epidemiology of ARI and respiratory viruses in schools, we developed School Knowledge of Infectious Diseases in Schools (School KIDS). Methods: School KIDS is a prospective, respiratory viral testing program in a large metropolitan school district (pre-kindergarten-12th grade) in Kansas City, Missouri. During the 2022-2023 school year, all students and staff were eligible to participate in surveillance respiratory viral testing at school by submitting observed self-administered nasal swabs monthly. Participants could also submit a nasal swab for on-demand symptomatic testing when experiencing ≥1 ARI symptom, including cough, fever, nasal congestion, runny nose, shortness of breath, sore throat, and/or wheezing. Swabs were tested in a research laboratory using multipathogen respiratory polymerase chain reaction assays. Participants were evaluated for ongoing viral shedding by collecting two weekly nasal swabs (i.e., convalescent), following initial on-demand symptomatic testing. Participants were asked to complete an electronic survey to capture the presence and type of ARI symptom(s) before the collection of respiratory swabs. Results: From 31 October 2022 to 29 June 2023, School KIDS enrolled 978 participants, including 700 students, representing 3.4% of the district student population, and 278 staff members. Participants submitted a median of six surveillance, one symptomatic, and two convalescent specimens during the study period. A total of 6,315 respiratory specimens, including 4,700 surveillance, 721 on-demand symptomatic, and 894 convalescent specimens, were tested. Overall, a virus was detected in 1,168 (24.9%) surveillance and 363 (50.3%) symptomatic specimens. Of the 5,538 symptom surveys sent to participants before scheduled surveillance testing, 4,069 (73.5%) were completed; ARI symptoms were reported on 1,348 (33.1%) surveys. Conclusion: Respiratory surveillance testing in schools is feasible and provides novel information about respiratory virus detections in students and staff attending school. Schools are an important community setting, and better knowledge of respiratory virus circulation in schools may be useful to identify respiratory virus transmission in the community and assess the impact of effective infection prevention measures.

SARS-CoV-2 Viral Shedding and Rapid Antigen Test Performance - Respiratory Virus Transmission Network, November 2022-May 2023.

As population immunity to SARS-CoV-2 evolves and new variants emerge, the role and accuracy of antigen tests remain active questions. To describe recent test performance, the detection of SARS-CoV-2 by antigen testing was compared with that by reverse transcription-polymerase chain reaction (RT-PCR) and viral culture testing during November 2022-May 2023. Participants who were enrolled in a household transmission study completed daily symptom diaries and collected two nasal swabs (tested for SARS-CoV-2 via RT-PCR, culture, and antigen tests) each day for 10 days after enrollment. Among participants with SARS-CoV-2 infection, the percentages of positive antigen, RT-PCR, and culture results were calculated each day from the onset of symptoms or, in asymptomatic persons, from the date of the first positive test result. Antigen test sensitivity was calculated using RT-PCR and viral culture as references. The peak percentage of positive antigen (59.0%) and RT-PCR (83.0%) results occurred 3 days after onset, and the peak percentage of positive culture results (52%) occurred 2 days after onset. The sensitivity of antigen tests was 47% (95% CI = 44%-50%) and 80% (95% CI = 76%-85%) using RT-PCR and culture, respectively, as references. Clinicians should be aware of the lower sensitivity of antigen testing compared with RT-PCR, which might lead to false-negative results. This finding has implications for timely initiation of SARS-CoV-2 antiviral treatment, when early diagnosis is essential; clinicians should consider RT-PCR for persons for whom antiviral treatment is recommended. Persons in the community who are at high risk for severe COVID-19 illness and eligible for antiviral treatment should seek testing from health care providers with the goal of obtaining a more sensitive diagnostic test than antigen tests (i.e., an RT-PCR test).

Detection of a Human Adenovirus Outbreak, Including Some Critical Infections, Using Multipathogen Testing at a Large University, September 2022-January 2023.

Background: Human adenoviruses (HAdVs) can cause outbreaks of flu-like illness in university settings. Most infections in healthy young adults are mild; severe illnesses rarely occur. In Fall 2022, an adenovirus outbreak was identified in university students. Methods: HAdV cases were defined as university students 17-26 years old who presented to the University Health Service or nearby emergency department with flu-like symptoms (eg, fever, cough, headache, myalgia, nausea) and had confirmed adenovirus infections by polymerase chain reaction (PCR). Demographic and clinical characteristics were abstracted from electronic medical records; clinical severity was categorized as mild, moderate, severe, or critical. We performed contact investigations among critical cases. A subset of specimens was sequenced to confirm the HAdV type. Results: From 28 September 2022 to 30 January 2023, 90 PCR-confirmed cases were identified (51% female; mean age, 19.6 years). Most cases (88.9%) had mild illness. Seven cases required hospitalization, including 2 critical cases that required intensive care. Contact investigation identified 44 close contacts; 6 (14%) were confirmed HAdV cases and 8 (18%) reported symptoms but never sought care. All typed HAdV-positive specimens (n = 36) were type 4. Conclusions: While most students with confirmed HAdV had mild illness, 7 otherwise healthy students had severe or critical illness. Between the relatively high number of hospitalizations and proportion of close contacts with symptoms who did not seek care, the true number of HAdV cases was likely higher. Our findings illustrate the need to consider a wide range of pathogens, even when other viruses are known to be circulating.

Deaths Associated with Pediatric Hepatitis of Unknown Etiology, United States, October 2021-June 2023.

During October 2021-June 2023, a total of 392 cases of acute hepatitis of unknown etiology in children in the United States were reported to Centers for Disease Control and Prevention as part of national surveillance. We describe demographic and clinical characteristics, including potential involvement of adenovirus in development of acute hepatitis, of 8 fatally ill children who met reporting criteria. The children had diverse courses of illness. Two children were immunocompromised when initially brought for care. Four children tested positive for adenovirus in multiple specimen types, including 2 for whom typing was completed. One adenovirus-positive child had no known underlying conditions, supporting a potential relationship between adenovirus and acute hepatitis in previously healthy children. Our findings emphasize the importance of continued investigation to determine the mechanism of liver injury and appropriate treatment. Testing for adenovirus in similar cases could elucidate the role of the virus.

Identification of Large Adenovirus Infection Outbreak at University by Multipathogen Testing, South Carolina, USA, 2022.

Using multipathogen PCR testing, we identified 195 students with adenovirus type 4 infections on a university campus in South Carolina, USA, during January-May 2022. We co-detected other respiratory viruses in 43 (22%) students. Continued surveillance of circulating viruses is needed to prevent virus infection outbreaks in congregate communities.