The Fraser Health Authority is giving elderly patients a flu shot containing a substance used to boost the vaccine's effectiveness. (Jeff McIntosh/Canadian Press)

The Fraser Health Authority is working to improve the flu shot’s effectiveness for seniors with a targeted vaccine program.

According to the U.S. Centers for Disease Control, the latest vaccine was about 50 per cent effective overall, and only about 27 per cent effective for seniors. The flu vaccine's effectiveness varies from year to year depending on the type of strain.

"This year we know that it's been disappointing in some groups,” said Dr. Paul Van Buynder with the Fraser Health Authority.

But the flu shot’s effectiveness tends to be even lower for seniors, who generally don't respond as well to the vaccine.

The Fraser Health Authority is working to change that with a targeted vaccine for seniors.

“In the Lower Mainland, we've started to use an alternate vaccine for the elderly, an adjuvanted vaccine, because we've known for some time we've need to use a better vaccine,” Buynder said.

An adjuvant is a substance used to boost the vaccine's effectiveness.

Van Buynder says the targeted flu shot was about 70 per cent effective last year.