Older adults are at high risk for serious complications from flu and account for a majority of flu-related deaths and hospitalizations. H3N2 influenza viruses typically hit this age group particularly hard and have been associated with higher mortality than infections by H1N1 or influenza B viruses. During the 2012-2013 season, when H3N2 viruses were dominant, high-dose flu vaccine was 36 percent more effective at preventing deaths in the Medicare beneficiaries studied, compared to standard-dose vaccine.