dssu

The duration of flu symptoms, by more than 1 day (median time, 53.7 hours vs 80.2 hours; P <.0001);

The duration of fever, by nearly 1 day (median time, 24.5 hours vs 42.0 hours; P <.0001);

The length of time viruses continued to be released from the body (median time of viral shedding, 24.0 hours vs 96.0 hours; P <.0001); and

The levels of virus in the nose and throat from 24 hours through 120 hours.

Relative to oseltamivir, baloxavir treatment resulted in similar median time to alleviation of symptoms (median, 53.5 hours for baloxavir vs 53.8 hours for oseltamivir; P = .7560) and similar time to resolution of fever reduction (median, 24.4 hours vs 24.0 hours; P = .9225), respectively.

However, baloxavir treatment was associated with significantly reduced viral shedding duration (24.0 hours vs 72.0 hours; P < .0001) and significantly lower levels of virus in the nose and throat at 24 hours and 72 hours.

"It is unclear why the time to alleviation of symptoms was similar in the baloxavir group and the oseltamivir group even though baloxavir showed greater antiviral activity," the authors write. "The findings suggest that the symptom benefit of antiviral agents may have a ceiling in self-limited influenza illness in adults, perhaps because viral replication levels are decreasing by the time of presentation and illness pathogenesis is linked to host proinflammatory responses."

Overall, baloxavir was well-tolerated and had a lower incidence of adverse events reported (20.7%) compared with placebo (24.6%) or oseltamivir (24.8%). The most common adverse events were diarrhea (3%), bronchitis (2.6%), nausea (1.3%), and sinusitis (1.1%).