Clinical diagnostic criteria for isolating patients admitted to hospital with suspected pandemic influenza

[Extract] Australian hospitals have now experienced the first wave of pandemic H1N1 influenza during a southern hemisphere winter. Patients admitted to Australian hospitals with suspected pandemic influenza during this period were identified by use of approved national clinical diagnostic criteria.1 However, the imprecise nature of clinical diagnosis limited the ability of hospitals to isolate infectious patients effectively before the laboratory confirmation of infection (which typically takes a minimum of 48 h).

Concern about our reliance on these criteria to isolate potentially infectious patients led us to analyse our early experience with pandemic influenza at the two teaching hospitals in the Gold Coast region of Queensland. We collected nasopharyngeal and throat specimens and reviewed clinical and laboratory data on all 346 patients admitted to the hospitals with acute respiratory disease during the period from May 24 to Aug 16, 2009. Pandemic H1N1 influenza virus RNA was detected in specimens collected from 106 of 346 patients (31%).