Written by Clay Smith
Oseltamivir shortens duration of influenza by 1 day. The effect on duration is muted in young, healthy patients (0.7 days shorter) and amplified in older patients with comorbidities (2-3 days shorter).
Why does this matter?
The effectiveness of oseltamivir has been called into question. Most of the RCTs, including a meta-analysis of these RCTs, were funded by Roche, and most of the authors were employees of Roche or had conflicts of interest. In the meta-analysis mentioned above, the authors did not have access to the primary data for 8 of the 10 RCTs. You really must read the BMJ exposé about oseltamivir. What does this non-industry funded version show? By the way, it might be helpful for you to reread the recent IDSA guidelines and refresh your memory this flu season.
It really shaves a day off the flu
This was an open label RCT in a primary care setting spanning three flu seasons, including patients over age 1 with influenza-like illness, over half of which were confirmed using PCR flu testing. They found that, in aggregate, patients had 1 day shorter duration of illness. The effect was more muted in young, healthy patients. However, in patients over 65 with comorbidities, the effect was magnified, shaving 2 to 3 days off the duration of illness. The downside to oseltamivir was a higher rate of nausea and vomiting. Prior studies suggested treatment within 24 hours may add greater benefit. This study did not confirm this and found nearly equal benefit if started within 72 hours. The big issue with this study is that it was unblinded. Placebo effect is very powerful. Patients knew they were getting active drug or no drug (aka “usual therapy”). The recovery criteria were self-reported and subjective (i.e. less headache, less achy). Treatment had no impact on hospitalization or pneumonia rates. This study confirms what prior industry funded articles have concluded – namely, that oseltamivir reduces flu duration by about 1 day.
Oseltamivir plus usual care versus usual care for influenza-like illness in primary care: an open-label, pragmatic, randomised controlled trial. Lancet. 2019 Dec 12. pii: S0140-6736(19)32982-4. doi: 10.1016/S0140-6736(19)32982-4. [Epub ahead of print]
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