Epidemiological impact of recent influenza viruses in various countries.


During recent years, although influenza B has given rise to epidemics every 3-5 years, influenza A has caused greater concern to those responsible for the surveillance of the disease. The usual cycle of influenza A waves every 2 or 3 years was modified in many countries by the yearly appearance of new variants of the virus A/Hong Kong/68 (A/England/42/72, A… (More)


2 Figures and Tables