Story of Influenza Antivirals: Part 30

The claimed effect on prophylaxis, pre-and post-exposure

Another key claim made by researchers and manufacturers was that prophylactic oseltamivir and zanamivir could, if taken soon after or before contact with an influenza case, prevent spread. Roche, after the launch of oseltamivir, claimed that the drug did not prevent infection in healthy people but rather stopped the newly formed virions from budding from the infected cell and spreading widely to cause symptoms and complications.

Oseltamivir/Tamiflu effects

We found that symptomatic influenza was lower in the oseltamivir arms compared to placebo in four studies of prophylaxis. The relative risk looked impressive, with a 55% reduction. There were no differences for all other influenza outcomes and, of course, complications. 

In household prophylaxis, one small study (WV15799) showed an impressive 80% reduction in symptomatic influenza in the oseltamivir arm compared to placebo. However, the same study also showed there was no significant reduction in asymptomatic influenza. 

The Roche trial…