Researchers at the Cochrane Collaboration and BMJ (formerly British Medical Journal) are questioning the U.S. government’s spending of $1.3 billion on stockpiling antivirals such as Tamiflu® and Relenza®, noting that there is no credible evidence demonstrating the two neuraminidase inhibitors lower hospital admissions and complications of influenza. While clinical trials showed that influenza-like symptoms in Tamiflu and Relenza takers were alleviated a half-day sooner than patients who took a placebo, the antivirals actually increased occurrences of nausea, vomiting, headaches, psychiatric disturbances, and renal events. Researchers also found that there was insufficient evidence to demonstrate Tamiflu and Relenza prevent person-to-person spreading of influenza.
“We now have the most robust, comprehensive review on neuraminidase inhibitors that exists,” said BMJ Editor-in-Chief David Tovey. “Initially thought to reduce [hospitalizations] and serious complications from influenza, the review highlights that Tamiflu is not proven to do this, and it also seems to lead to harmful effects that were not fully reported in the original publications. This shows the importance of ensuring that trial data are transparent and accessible.”
According to Cochrane and BMJ, the evidence that was previously presented to government agencies regarding Tamiflu and Relenza, which subsequently led to the expensive stockpiling of the antivirals, was incomplete. However, the Review, “Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children,” involved 20 Tamiflu and 26 Relenza trials, involving over 24,000 people. “Drug approval and use cannot be based on biased or missing information any longer,” stated review authors Dr. Tom Jefferson, Dr. Carl Heneghan, and Dr. Peter Doshi. “We risk too much in our population’s health and economy. This updated Cochrane review is the first time a Cochrane systematic review has been based only on clinical study reports and regulator’s comments. It is the first example of open science in medicine using full clinical study reports available without conditions. And therefore the conclusions are that much richer. We urge people not to trust in published trials alone or on comment from conflicted health decision makers, but to view the information for themselves.”
According to Cochrane, “the review clearly recommends that guidance on the use of both neuraminidase inhibitors (oseltamivir and zanamivir) in the prevention or treatment of influenza should be revised to take account of the evidence of small benefit and increased risk of harms.” In addition, given the lack of evidence that supports original claims of the antivirals’ benefits, the review raised questions on whether stockpiling of the drugs is still justifiable.