Which Flu Antiviral Protects Best

The peer-reviewed journal Clinical Infectious Diseases published a study on February 1, 2022, that found the influenza antiviral Xofluza (Baloxavir marboxil) more effective than Tamiflu (oseltamivir) in preventing household flu transmission in Japan.

Xofluza is a selective cap-dependent endonuclease inhibitor, approved in Japan in February 2018, as a single oral dose for treating influenza types A and B.

In a model using an insurance claims database, the proportion of families with a secondary influenza infection was estimated to be twice as high if index cases received oseltamivir rather than baloxavir marboxil (19.35% vs. 9.57%, respectively).

Regardless of influenza viral type, a multivariate analysis showed a median odds ratio (2.5th and 97.5th percentiles) of 1.73 (1.68-1.77), suggesting more intrafamilial transmission with oseltamivir, the authors wrote.

'Based on a simulation model factoring in agent-specific infectivity, treating influenza in the first family member with baloxavir marboxil, than with oseltamivir, may contribute to a greater reduction in intra-familial influenza transmission.'

Notably, Japan reports the second-highest number of influenza cases in the Western Pacific region, after China.

The U.S. CDC's website stated in December 2021, antiviral treatment is recommended as soon as possible for patients with suspected or confirmed influenza who are hospitalized, have severe, complicated, or progressive illness; or are at higher risk for influenza complications.

Furthermore, 'decisions about starting antiviral treatment for patients with suspected influenza should not wait for laboratory confirmation of influenza virus infection,' says the CDC.

The study's corresponding author is takahiro-takazono@nagasaki-u.ac.jp.