Healthcare workers (HCWs) are at the frontline of any public health outbreak response, and therefore among the most vulnerable to emerging infectious diseases (EIDs), evident by the extent of morbidity and mortality caused by SARS and other outbreaks [2] [3] [4] [5] [6] [7] . In the past, hospitals have become amplifiers of newly emerging infections due to transmission from patients to HCWs, owing to ineffective infection control measures and failing to recognise a new pathogen [4, 8] . HCWs may therefore be the first to experience secondary transmission of an EID, and consequently a population where clusters of cases are first to appear. Monitoring HCWs' health could provide an important opportunity to detect newly circulating infections earlier, enhancing current efforts for their identification and control.