Just one dose of antiviral baloxavir marboxil significantly reduced transmission of influenza within households, reported a recent study in The New England Journal of Medicine. The findings constitute the first robust evidence of an antiviral treatment reducing spread of influenza among close contacts.
"There's always been a question: Could antivirals, which are known to shorten the duration of influenza when used early in treatment, also prevent the spread of influenza," said study author Arnold Monto, Professor Emeritus of Epidemiology at the University of Michigan, in Medical Xpress.
"We have had drugs which treat influenza in use for many years, but it has been unclear whether there was any reduction in transmission from the sick person. It also was not clear whether this was because no study was designed specifically to look for a reduction in spread, or if no spread was taking place,” he added.
For the study, researchers conducted a phase 3b trial to assess the efficacy of single-dose baloxavir to reduce influenza transmission from index patients to household members. They included 1457 index patients aged between 5 and 64 years old, and 2681 household contacts. Index patients received either baloxavir or a placebo within 48 hours of symptom onset.
The primary endpoint was transmission of influenza virus from an index patient to a household contact by day 5. Transmission of influenza virus by day 5 that resulted in symptoms was a secondary endpoint.
Ultimately, the researchers found that baloxavir reduced viral transmission by 32%. While transmission resulting in symptomatic influenza was lower, it was not statistically significant. No new safety concerns emerged, with adverse events reported in 4.6% of baloxavir-treated patients compared to 7% in the placebo group.
“These results highlight baloxavir's potential not only to treat influenza but also to reduce its spread within communities. This dual effect could transform how we manage seasonal influenza and prepare for future pandemics,” Benjamin Cowling, Chair Professor of Epidemiology at the University of Hong Kong, said in a press release.
