Background Although a human adenovirus (HAdV) vaccine is available for military use, officers-in-training are not routinely vaccinated. We describe an HAdV-associated respiratory outbreak among unvaccinated cadets at the U.S. Coast Guard Academy and its impact on cadet training. Methods We defined a case as a cadet with new onset cough or sore throat during August 1–October 4, 2019. We reviewed medical records and distributed a questionnaire to identify cases and to estimate impact on cadet training. We performed real-time PCR testing on patient and environmental samples and whole genome sequencing on a subset of positive patient samples. Results Among the 1,072 cadets, 378 (35%) cases were identified by medical records (n=230) or additionally by the questionnaire (n=148). Of the 230 cases identified from medical records, 138 (60%) were male and 226 (98%) had no underlying conditions. From questionnaire responses, 113/228 (50%) cases reported duty restrictions. Of cases with respiratory specimens, 36/50 (72%) were HAdV positive; all 14 sequenced specimens were HAdV-4a1. Sixteen (89%) of 18 environmental specimens from the cadet dormitory were HAdV-positive. Conclusions The HAdV-4-associated outbreak infected a substantial number of cadets and significantly impacted cadet training. Routine vaccination could prevent HAdV respiratory outbreaks in this population.

A case report is presented of a 36-year-old U.S. Coast Guard aviator who had a single seizure while operating a helicopter on the ground. His seizure activity produced a loss of consciousness during which he pushed the cyclic to the left anterior quadrant that resulted in a ground mishap. No risk factors were identified in an extensive neurological workup. The current guidance for handling seizures in military aviation personnel is reviewed, along with considerations for treatment. Although the military aviation selection process carefully screens applicants for seizure history and potential, occasional seizures in the aviation population remain possible. Such events may result in military aircraft mishaps despite careful risk factor surveillance, as demonstrated by this case.