Last season, the flu was caused by the H1N1 and H3N2 viruses in roughly equal proportion, health officials said. The vaccine didn't protect against the H3N2 viruses. (ASSOCIATED PRESS)
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Last season, the flu was caused by the H1N1 and H3N2 viruses in roughly equal proportion, health officials said. The vaccine didn't protect against the H3N2 viruses. (ASSOCIATED PRESS)
