According to a report by the CDC, the 2016-17 flu vaccine was mostly ineffective immunizing Americans age 65 and older against the illness last winter.
The vaccine was about 42% effective in preventing illness severe enough to send a patient to the doctor’s office. But it was essentially ineffective protecting some age groups. That includes people 65 and older — the group that’s hardest hit by flu, suffering the most deaths and hospitalizations.
The flu-related hospitalization rate for older adults was the highest it’s been since the severe 2014-2015 flu season. Like that season, last winter was dominated by a kind of flu — Type A H3N2 — that tends to cause more deaths and serious illnesses than other seasonal flu viruses.