This year's flu vaccine is even more disappointing than previously reported, showing just 18 percent effectiveness against the dominant H3N2 strain of flu, health officials reported Thursday.
That's a drop from the 23 percent protection level estimated for the flu shot earlier in the season, said experts at the U.S. Centers for Disease Control and Prevention.
The situation for children was even worse. The CDC panel pegged the effectiveness of the injected vaccine for kids aged 2 to 8 to be just 15 percent.
And the nasal-spray version of the vaccine may not protect young children at all, health officials said.