Viral and bacterial upper respiratory tract infection in hospital health care workers over time and association with symptoms

Raina MacIntyre, C.; Chughtai, Abrar Ahmad; Zhang, Yi; Seale, Holly; Yang, Peng; Chen, Joshua; Pan, Yang; Zhang, Daitao; Wang, Quanyi

We found many co-infections in this study. Previous studies have demonstrated that a viral infection may facilitate bacterial colonisation or co-infection with S. pneumoniae [30] . This may be a significant concern as such co-infection has been associated with significantly higher morbidity and mortality [31] . A growing body of evidence suggests that the risk of bacterial respiratory infections is increased by co-infection with viruses and vice-versa, however bacterial respiratory tract infections are generally not considered a major occupational hazard. Despite documented outbreaks of Bordetella pertussis, Chlamydia pneumoniae and Mycoplasma pneumoniae [32] [33] [34] [35] [36] , there are few prospective studies of bacterial respiratory infections or colonization, nor consideration of the clinical implications for HCWs. The risk of coinfection has been reported in schools and daycare centres with subsequent community transmission [3] , but not in HCWs. It has also been suggested that viral infection may facilitate bacterial colonisation of the respiratory tract particularly with S. pneumoniae. Studies in mice have found that influenza virus infection increases the transmission and burden of pneumococcal disease [30] . Similar findings have been reported in other studies demonstrating significantly higher morbidity and mortality of cases with influenza virus co-infection with S. pneumoniae [37] . This is suggestive that the role and significance of viral infection in the nasopharynx may be complex, highlighting the need for further research into this topic.