The Molecular Epidemiology and Congregate Transmission Dynamics of Medically Attended Acute Respiratory Infections (MAARIs) at the United States Naval Academy (USNA) during Plebe Summer

Abstract Background Understanding the epidemiology of acute respiratory infections (ARIs) in congregate military settings is vital to force health protection. This analysis describes insights gleaned from the “Acute Respiratory Infections at the Academy” (ARIA) study regarding respiratory virus incidence and impact at the United States Naval Academy during ‘Plebe Summer’ 2023, an intense 6-week training for all incoming freshmen (plebes). Methods Residual nasal swabs collected as part of the standard-of-care work-up in midshipmen who presented to clinic with an ARI were sent for multiplex PCR testing and viral genomic sequencing. Corresponding patient demographics, symptoms, diagnoses, and outcomes were abstracted from medical records. Integrated epidemiological and viral genomic analyses were performed. Results During Plebe Summer 2023, 40% of incoming freshmen (473/1,187) sought healthcare for at least one ARI, as did 71 upperclassmen. Swabs were collected in 598 of 615 ARIs (97%), among which 324 (54%) tested positive for at least one virus; 2+ viruses were detected in 52/324 (16%). Rhinovirus/enterovirus was most frequently detected, followed by SARS-CoV-2; several SARS-CoV-2 variants, all Omicron sub-lineages, were identified. There was considerable symptom overlap among MAARIs in which different viruses were detected. Most (83%) midshipmen with a medically attended ARI (MAARI) spent at least one day sick-in-quarters (SIQ). SARS-CoV-2 detections were associated with the longest SIQ durations. Conclusions Plebe Summer 2023 was characterized by high MAARI attack rates, considerable viral diversity and viral co-detections, and substantial training days lost. ARIA highlights the importance of ongoing characterization of ARIs in congregate populations to help inform mitigation strategies.