Single-Dose Baloxavir Treatment Can Reduce Influenza Transmission

THURSDAY, April 24, 2025 (HealthDay News) — A single-dose baloxavir treatment can reduce influenza transmission from index patients to household contacts, according to a study published in the April 24 issue of the New England Journal of Medicine.

Arnold S. Monto, M.D., from the University of Michigan School of Public Health in Ann Arbor, and colleagues examined the efficacy of single-dose baloxavir treatment to reduce influenza transmission from index patients to household contacts in a multicountry, phase 3b trial. Influenza-positive index patients aged 5 to 64 years were randomly assigned to receive baloxavir or placebo within 48 hours after symptom onset (726 and 731 patients, respectively).

The researchers found that transmission of laboratory-confirmed influenza was significantly lower with baloxavir than placebo by day 5 (adjusted incidence, 9.5 versus 13.4 percent; adjusted odds ratio, 0.68; 95.38 percent confidence interval, 0.50 to 0.93; P = 0.01), with an adjusted relative risk reduction of 29 percent. By day 5, the adjusted incidence of transmission of influenza virus that resulted in symptoms was 5.8 and 7.6 percent with baloxavir and placebo, respectively, but the difference was not significant (adjusted odds ratio, 0.75; 95.38 percent confidence interval, 0.50 to 1.12; P = 0.16). During the follow-up period, emergence of drug-resistant viruses occurred in 7.2 percent of index patients in the baloxavir group; there were no resistant viruses detected in household contacts. There were no new safety signals reported.

“Although vaccines will remain the primary control measure for influenza epidemics and pandemics, antiviral drugs play a complementary role, particularly in a pandemic scenario, as well as in persons who are not vaccinated seasonally,” the authors write.

Several authors disclosed ties to F. Hoffmann-La Roche, which manufactures baloxavir and funded the study.

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