Flu shot only 36 percent effective

NEWYORK » The flu vaccine is doing a poor job protecting older Americans and others against the bug that’s causing most illnesses.

Preliminary figures released Thursday suggest the vaccine is 36 percent effective overall in preventing flu illness severe enough to send a patient to the doctor’s office.

There’s only been one other time in the last decade when the flu vaccine did a worse job.

Most illnesses this winter have been caused by a nasty kind of flu called Type A H3N2. The vaccine was only 25 percent effective against that type.

This kind of virus tends to causemore suffering and have been responsible for theworst recent flu seasons. But experts have wondered whether low vaccine effectiveness is another reason for the surprisingly severe season hitting the United States this winter.

The Centers for Disease Control and Prevention published the esimates.

The vaccine provided good protection — 67 percent effective — against another common kind of flu virus, Type A H1N1, which has not been seenmuch this winter. And it was 42 percent effective against Type B flu viruses.

The vaccine worked relatively well in young children, but it performed worse in older people, including seniors who are most vulnerable. Against H3N2, the vaccine was 51 percent effective in children ages 6 months to 8years.