Middle ear pressure (MEP) abnormalities are frequently observed during influenza virus infection and may serve as surrogate markers for the risk of otitis media. MEP abnormalities were evaluated in adult volunteers who were inoculated with influenza A/Texas/36/91(H1N1) or B/Yamagata/88 virus and given the antiviral zanamivir (GG167) intranasally as prophylaxis or early treatment in randomized, double-blind, placebo-controlled trials. In the influenza A prophylaxis studies, 15% of 61 zanamivir

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... cipients versus 61% of 33 placebo recipients showed significant MEP abnormalities (P õ .01). In the influenza A early treatment trial, 32% of 31 infected zanamivir recipients versus 73% of 26 infected placebo recipients developed MEP abnormalities (P õ .01). In the influenza B prophylaxis trial, 16% of 25 zanamivir versus 44% of 9 placebo recipients showed abnormalities (P Å .09). These findings indicate that the neuraminidase inhibitor zanamivir, which is effective in reducing experimental influenza illness, provides protection against the development of MEP abnormalities.