NEW YORK (AP) — The flu vaccine was ineffective in protecting older Americans last winter against the illness, even though the vaccine was well-matched to the flu bugs going around.

U.S. health officials on Wednesday released new vaccine data. They showed the vaccine did a so-so job overall— it was about 42 percent effective in preventing illness severe enough to send a patient to a doctor’s office.

But it did a poor job 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 data were presented at a medical meeting in Atlanta. Annual flu shots are recommended for virtually all Americans age 6 months or older.