# P-2173. Respiratory Virus Detections among Asymptomatic Students and Staff Members in a Large Public School District in Kansas City, Missouri, 2023-2025

## TL;DR

This study found that 15% of asymptomatic students and staff in a Kansas City school district tested positive for respiratory viruses, with frequent detections of rhinovirus, seasonal coronaviruses, and SARS-CoV-2.

## Contribution

The study provides new insights into asymptomatic respiratory virus transmission in school settings, revealing consistent positivity rates across the school year.

## Key findings

- Viral positivity was 15% among asymptomatic participants, with rhinovirus/enterovirus being the most commonly detected virus.
- Younger students (preK and elementary) had significantly higher odds of viral positivity compared to staff and middle/high-school students.
- Viral positivity showed little seasonal variation despite ongoing surveillance over two school years.

## Abstract

While the epidemiology of acute respiratory illness (ARI) among those seeking medical care is well studied, less is known about ARI in non-medical settings (e.g., schools), especially in individuals not exhibiting ARI symptoms. We examined respiratory virus detections among asymptomatic students and staff in a public school district.Table 1:Frequency of Respiratory Viral Detection Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness SymptomsFigure 1:Viral Positivity Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms, by Collection Month and School YearNote: Viral positivity defined as detection of ≥1 respiratory virus from a respiratory surveillance swab. Testing for the 2023-24 school year began in November 2023. Testing for the 2024-25 school year is ongoing.

Frequency of Respiratory Viral Detection Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms

Viral Positivity Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms, by Collection Month and School Year

Note: Viral positivity defined as detection of ≥1 respiratory virus from a respiratory surveillance swab. Testing for the 2023-24 school year began in November 2023. Testing for the 2024-25 school year is ongoing.

Knowledge of Infectious Diseases in Schools (School KIDS) is a prospective respiratory virus surveillance program in a preK-12th grade public school district in Kansas City, MO. From 2023—2025, student/staff participants self-collected monthly anterior nares swabs. Specimens were tested by multiplex PCR for adenovirus, human metapneumovirus, influenza, parainfluenza, respiratory syncytial virus, rhinovirus/enterovirus (RV/EV), seasonal coronaviruses (sCoV), and SARS-CoV-2. Prior to specimen collection, participants were asked about ARI symptoms (cough, fever, congestion, runny nose, shortness of breath, sore throat, and wheezing) in the past 7 days. Specimens from participants with no ARI symptoms (i.e., asymptomatic) were included in the analysis. Differences between positive (detecting ≥1 virus) and negative specimens were assessed. We used multilevel logistic models to compare odds of viral detection adjusting for school-level and season.Figure 2:Proportion of Virus Detections in Respiratory Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms by Specific VirusNote: the numbers above each bar indicate the frequency of positive detections. Of the 512 positive swabs, 27 had more than one virus detected. Therefore, total detected viruses were 543.Table 2:Adjusted Odds of Detecting ≥1 Respiratory Virus Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms

Proportion of Virus Detections in Respiratory Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms by Specific Virus

Note: the numbers above each bar indicate the frequency of positive detections. Of the 512 positive swabs, 27 had more than one virus detected. Therefore, total detected viruses were 543.

Adjusted Odds of Detecting ≥1 Respiratory Virus Among Respiratory Surveillance Swabs Collected from Students/Staff Reporting No Recent Acute Respiratory Illness Symptoms

Of 5398 specimens collected from 2023—2025, 3502 (65%) were from asymptomatic participants. Viral positivity among these specimens was 15% (n=512/3502). Viral positivity varied by school level (Table 1) but overall showed little seasonal variation (Figure 1). Most commonly detected viruses were RV/EV (56%), sCoV (23%) and SARS-CoV-2 (7%) (Figure 2). Compared with staff from middle/high-schools, increased odds of viral positivity were observed for preK (OR: 18.9 [4.9, 72.4]), elementary (OR: 5.7 [3.0, 10.7]), and middle-school students (OR: 2.4 [1.2, 4.7]) (Table 2).

Viral detections in asymptomatic students and staff were frequent (15%), with relatively consistent positivity (for any virus) throughout the school year. Public health strategies to mitigate respiratory viral transmission including cough/hand hygiene and staying home while sick, among others, may reduce both symptomatic and asymptomatic transmission

Brian R. Lee, PhD, MPH, Merck: Grant/Research Support Rangaraj Selvarangan, PhD, Altona: Grant/Research Support|Biomerieux: Advisor/Consultant|Biomerieux: Grant/Research Support|Biomerieux: Honoraria|Cepheid: Grant/Research Support|Hologic: Grant/Research Support|Hologic: Honoraria|Meridian: Grant/Research Support|Qiagen: Grant/Research Support