Baloxavir Protects Household Contacts From Influenza

immune response to influenza virus
Computer illustration of a plasma cell (B-cell, left) secreting antibodies (white) against influenza viruses (right). Antibodies bind to specific antigens, for instance viral proteins, marking them for destruction by phagocyte immune cells.
The percentage of patients in whom clinical influenza developed was significantly lower in baloxavir group.

HealthDay News — Baloxavir demonstrates postexposure prophylactic efficacy for preventing influenza in household contacts of index patients, according to a study published online July 8 in the New England Journal of Medicine.

Hideyuki Ikematsu, M.D., from Ricerca Clinica in Fukuoka, Japan, and colleagues conducted a randomized trial to assess the postexposure prophylactic efficacy of baloxavir in household contacts of index patients with confirmed influenza during the 2018 to 2019 season in Japan. A total of 752 household contacts of 545 index patients were randomly assigned to receive either a single dose of baloxavir or placebo in a 1:1 ratio (374 and 375 patients, respectively).

The researchers found that the percentage of patients in whom clinical influenza developed was significantly lower in the baloxavir versus the placebo group (1.9 versus 13.6 percent; adjusted risk ratio, 0.14). In high-risk, pediatric, and unvaccinated subgroups of participants, baloxavir was effective. Regardless of symptoms, the risk for influenza infection was lower with baloxavir than placebo (adjusted risk ratio, 0.43). The incidence of adverse events was similar in the baloxavir and placebo groups (22.2 versus 20.5 percent).

“The positive findings with baloxavir prophylaxis in reducing the spread of influenza virus within households suggest the need for studying its prophylactic efficacy in other nonhousehold settings,” the authors write.

The study was funded by Shionogi.

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