Why aren’t the US Centers for Disease Control and Food and Drug Administration speaking with one voice on flu?

The US Centers for Disease Control and Prevention has launched an ambitious campaign urging people to take an antiviral drug for flu if one is prescribed by a doctor, saying that it could “save lives.” The claim is at the center of a heated controversy.

The Food and Drug Administration told The BMJ that data submitted to it for review do not support the claim that the neuraminidase inhibitor oseltamivir (marketed by Genentech and Roche as Tamiflu) “saves lives.” The FDA said that oseltamivir “has not been proven to have a positive impact on the potential consequences (such as hospitalizations, mortality, or economic impact) of seasonal, avian, or pandemic influenza.”

Stephanie Yao, an FDA spokeswoman, told The BMJ that the CDC may have considered other studies not submitted to the FDA.

The CDC’s director, Thomas Frieden, told The BMJ in an email that the “CDC’s review of the evidence provides consistent support for the observation that early treatment with neuraminidase inhibitors can reduce the risk of death among hospitalized patients with laboratory-confirmed influenza infection . . . As is often the case, assessing the effectiveness of interventions on less common outcomes (such as deaths) requires the use of observational studies.”

Frieden cited a meta-analysis of randomized controlled trial data by Joanna Dobson and colleagues, published in The Lancet 30 January,1 saying that the meta-analysis “demonstrates a reduction in hospitalization after outpatient receipt of oseltamivir treatment, adding to the growing body of evidence which supports the public health benefit of using these drugs for more than treatment of uncomplicated influenza.”

In public interviews Frieden has made expansive claims about patients with flu who have not been admitted to hospital, telling National Public Radio in Boston on 9 January, “The evidence indicates that [oseltamivir] will shorten how long you’re sick, might …