It was beforehand believed that influenza pandemics occurred at 10- to 14-yr intervals, but it has been over 30 years since H3N2 viruses appeared. Viruses were first isolated in Hong Kong in July 1968. If you loved this article and you would certainly like to receive more details concerning sialic acid powder manufacturers kindly go to our website. Widespread illness with increased excess mortality was observed within the United States in the course of the winter of 1968-1969. Attack rates had been highest (40%) amongst 10- to 14year-outdated kids.