Research news: September 2013
Lancet2013; doi:10.1016/ S0140-6736(13)61207-6
Lancet2013; doi:10.1016/ S0140-6736(13)61171-X
The latest epidemiological studies of avian H7N9 influenza A virus report a case fatality rate of 36% (95% CI 26% to 45%) among the 123 individuals admitted to hospital with confirmed infections. In this early series, infections and fatalities were clustered among older adults, mostly men (87/123, 71%). Most infected individuals who were admitted to hospital needed intensive care or mechanical ventilation, or died (83%, 76% to 90%).
It’s harder to gauge severity of infections in the broader population, say the authors. We don’t yet have a clear idea of overall infection rates from surveillance of people with influenza-like illnesses. Early indications are that eight people with confirmed infection (out of a total of 131) recovered after a mild illness. The best guess fatality rate for any symptomatic person infected with H7N9 lies somewhere between 160 (63 to 460) and 2800 (1000 to 9400)