The Cochrane Collaboration, a network of independent scientists who evaluate medical interventions using strict objective criteria, has raised questions about the effectiveness of the antiviral flu medicines Tamiflu and Relenza. The research published in the BMJ included analysis of data from 20 trials of Tamiflu and 26 of Relenza. There were more than 24,000 people included in these studies.
What Did the Studies Show?
The Cochrane investigators found a reduction in duration of symptoms of approximately one half day for people taking Tamiflu rather than a placebo. There was no strong evidence that Tamiflu cut hospitalizations or serious complications in children or adults, although it did produce side effects such as nausea and vomiting.
Relenza did prevent symptomatic influenza, though the effect was modest. If the drug was taken by 51 people, it would prevent one case of flu. There were no data to show whether Relenza reduced hospital admissions. There is also no evidence to prove that these antiviral medications prevent person-to-person transmission of the influenza virus as public health authorities had hoped and assumed.
What Were the Challenges?
The editor in chief of the BMJ commented,
“This review is the result of many years of struggles to access and use trial data, which was previously unpublished and even hidden from view. It highlights with certainty that future decisions to purchase and use drugs, particularly when on a mass scale, must be based on a complete picture of the evidence, both published and unpublished. We need the full data from clinical trials made available for all drugs in current use. With the new European Clinical Trials Directive bringing in rules for future drugs, it highlights the enormous challenge we face. We need the commitment of organizations and drug companies to make all data available, even if it means going back 20 years. Otherwise we risk another knee-jerk reaction to a potential pandemic. And can we really afford it?”
One of the authors of the Cochrane reviews wrote about the difficulties of getting access to the data. It is an interesting read.
If you are primarily interested in what to do about the flu, though, you may want to read about other approaches to easing the symptoms of influenza in our Guide to Colds, Coughs & the Flu.
