Evidence for cross-protection against subsequent febrile respiratory illness episodes from prior infections by different viruses among singapore military recruits 2009-2014

Abstract

Background. Few studies have evaluated the relative cross-protection conferred by infection with different groups of viruses through studies of sequential infections in humans. We investigated the presence of short-lived relative cross-protection conferred by specific prior viral infections against subsequent febrile respiratory illness (FRI). Methods. Men enlisted in basic military training between December 2009 and December 2014 were recruited, with the first FRI as the study entry point. ResPlex II assays and real-time polymerase chain reaction assays were used to detect viral pathogens in nasal wash samples, and survival analyses were performed to determine whether infection with particular viruses conferred short-lived relative cross-protection against FRI. Results. Prior infection with adenovirus (hazard ratio [HR], 0.24; 95% confidence interval [CI],.14-.44) or influenza virus (HR, 0.52; 95% CI,.38-.73) conferred relative protection against subsequent FRI episode. Results were statistically significant even after adjustment for the interval between enlistment and FRI (P