Flu Patients Get Better Sooner With Oseltamivir, Pragmatic Trial Shows

By Reuters Staff

NEW YORK (Reuters Health) - A study from Europe provides estimates of the likely benefits of adding oseltamivir to usual care for patients with influenza-like illness.

According to the study, patients who take oseltamivir recover one day sooner on average than those who don't. And older, sicker patients with comorbid conditions are likely to recover two to three days sooner with the antiviral.

Writing The Lancet, Dr. Chris Butler of the University of Oxford, U.K., and colleagues note that primary-care doctors in Europe often don't prescribe antivirals for flu-like illness, mostly because they are thought to be ineffective and because it's not clear who might benefit the most.

To inform practice, they tested whether adding oseltamivir to usual primary care for patients with influenza-like illness reduces time to recovery overall and in key subgroups. They recruited 3,266 people from 15 European countries during three influenza seasons, with 1,629 allocated to usual care plus oseltamivir and 1,637 to usual care only.

Time to recovery (defined as return to usual activities, with fever, headache, and muscle ache minor or absent) was significantly shorter in people who took oseltamivir overall and in most of the prespecified subgroups, the authors report.

The estimated absolute benefit from oseltamivir was 1.02 days on average. In the subgroups, the absolute benefit ranged from 0.70 days in patients younger than 12 years, with less severe symptoms, no comorbidities and shorter previous illness duration to 3.20 days in patients 65 years or older who had more severe illness, comorbidities and longer previous illness duration.

About half of participants had PCR-confirmed influenza infection but the benefit of oseltamivir was evident regardless of the test result. And there was no evidence of a differential effect between people positive for influenza and those positive for other viruses or between those infected with influenza A or B.

In addition, while previous trials have found relatively greater benefit when patients start treatment within 24 hours of symptom onset, there was no additional benefit from earlier treatment in this trial. Starting oseltamivir 48 to 72 hours after symptom onset appears to give similar benefit to earlier initiation, the authors report.

Participants on oseltamivir reported more vomiting or nausea. New or worsening symptoms of vomiting or nausea occurred in 21% of participants on oseltamivir group versus 16% of the control group.

The co-authors of a comment in The Lancet say the results of this study "provide some support for broader use of neuraminidase inhibitors during seasonal peaks, especially in high-risk individuals."

But Dr. Nelson Lee of the University of Alberta, in Edmonton, Canada, and Dr. Michael Ison of Northwestern University in Chicago also caution that the findings "should not be interpreted as efficacy of neuraminidase inhibitors for non-influenza viruses, such as respiratory syncytial virus and parainfluenza, that cause influenza-like illness."

Other "important" research questions, they note, are whether antiviral treatment for influenza in primary care can reduce antibiotic use and household transmission, and have an overall effect on community outbreaks. A cost-effectiveness analysis would aid decision-making.

The study had no commercial funding. Some of the authors disclosed ties to Roche, which markets oseltamivir as Tamiflu.

SOURCE: https://bit.ly/2s24e25 and https://bit.ly/2S5mrXf Lancet, online December 12, 2019.

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