HLTH 210 Chapter Notes - Chapter .: Northern Hemisphere, World Health Organization, Flu Season
23 Mar 2018
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Document Summary
Influenza a (h3n2) viruses predominated, and the preliminary estimate of vaccine effectiveness against influenza a (h3n2) was only 10%. Vaccine mismatches have occurred in years in which circulating influenza strains change after the decision is made about vaccine composition. Ex) during the 2014 2015 influenza season in the united states, more than 80% of the circulating influenza a (h3n2) viruses that were characterized differed from the vaccine virus, 13% vaccine effectiveness. Cornerstone of influenza prevention and epidemic control is strain- specific vaccination. Flu is subject to continual antigenic changes ( antigenic drift ) Vaccine updates are recommended by the who each february for the. Northern hemisphere and each september for the southern hemisphere. Seasonal influenza epidemics cause 3 million to 5 million severe cases and. 300,000 to 500,000 deaths globally each year, according to the world health. In general, estimates of vaccine effectiveness range from 40 to 60%, which is lower than that for most licensed noninfluenza vaccines.
