This year's flu vaccine practically didn't work at all for people over 65 according to the CDC.
It was effective in just 9% of those cases.
Government researchers say rates of hospitalization and death for the most common strain of flu this year were some of the highest ever seen. Doctors still don't know why.
Despite those findings the flu shot is still recommended. The vaccine did help more than half of those under 65.
MORE: Fighting the flu