Effect of Baloxavir Marboxil vs Oseltamivir on Familial Influenza Transmission

CDC Declares Flu Epidemic After Death of 15 Children
CDC Declares Flu Epidemic After Death of 15 Children
Researchers compared the incidence of intra-familial influenza transmission after treatment of the first family member with baloxavir marboxil vs oseltamivir.

Treating the first family member who contracts influenza with baloxavir marboxil (BXM) rather than with oseltamivir (OTV) may contribute to a greater reduction in intra-familial influenza transmission, according to a study published in Clinical Infectious Diseases.

Studies have suggested that treatment of the first family member who contracts influenza infection (index case [IC]) with an anti-influenza agent may reduce intra-familial transmission of influenza without the need for prophylaxis in noninfected individuals. The efficacy of neuraminidase inhibitors such as OTV, zanamivir, laninamivir, and peramivir for the treatment of influenza has been abundantly reported; however, BXM was only recently approved in Japan based on the results from only 2 randomized controlled trials.

To further assess the effectiveness of BXM, researchers for the current study compared the incidence of intra-familial transmission of influenza between BXM and OTV using a simulation model. They identified ICs diagnosed with influenza during the 2018 to 2019 influenza season using a claims database. Families were classified into the BXM or OTV group by the drug dispensed to the ICs.

The investigators found that the median proportion of families with intra-familial transmission was 9.57% and 19.35% in the BXM (N=84,672) and OTV (N=62,004) groups, respectively. In addition, a multivariate odds ratio indicated a substantially higher incidence of intra-familial infections in the OTV group vs the BXM group. The researchers also found that subgroup analyses based on the IC’s age category, virus type, and month of onset revealed similar trends favoring BXM.

The researchers concluded, “Using the influenza intra-familial infection model, a national insurance claims database, and shared family codes, we derived that treatment with BXM substantially reduced the odds of intra-familial infection from an IC compared with treatment with OTV on a simulation basis.”

Disclosure: This research was supported by Shionogi & Co, Ltd. Please see the original reference for a full list of disclosures.


Miyazawa S, Takazono T, Hosogaya N, et al. Comparison of intra-familial transmission of influenza virus from index patients treated with baloxavir marboxil or oseltamivir using an influenza transmission model and a health insurance claims database. Clin Infect Dis. Published online February 1, 2022. doi:10.1093/cid/ciac068