Changes in Clinical Presentation and Epidemiology of Respiratory Pathogens Associated With Acute Respiratory Illness in Military Trainees After Reintroduction of Adenovirus Vaccine

Yun, Heather C.; Young, Adam N.; Caballero, Manuel Y.; Lott, Lisa; Cropper, Thomas L.; Murray, Clinton K.

The most significant strength of the study is the collection of a wide array of respiratory pathogen data alongside a detailed collection of clinical and demographic data, allowing thorough evaluations for ecologic niche replacement, as well as changes in clinical illness, throughout a major change in vaccine administration, in >2600 trainees. Others include the high uptake of Ad vaccine, and the consistency in access to care, living and training conditions, and preventive medicine measures throughout the study period. The study also has a number of limitations. This is a single center which, although spanning several years, cannot account for natural variability of respiratory pathogens here or at other training sites, and some pathogens were tested for only from a subset of samples. These represent a convenience sample of the overall burden of trainees presenting to medical care for respiratory illness. Trainees, for a number of reasons, may be reluctant to self-identify when ill and present for care. While we have no reason to believe this limitation changed over the course of the study, this limits the ability to extrapolate frequencies of detection to rates of disease. Since asymptomatic subjects are not captured, it also limits the ability to determine colonization vs correlation with clinical illness. However, study procedures and approaches to enrolling trainees were unchanged over the course of the study period. There may have been increases in healthcare-seeking behavior in 2009 during the influenza pandemic, and this year saw the highest number of enrollments over the course of the study. Finally, comorbidities in this group were not captured, although significant known comorbidities are typically disqualifying for military accession.