– The latest updated Cochrane Review: Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children, is based on full internal reports of 20 Tamiflu (oseltamivir) and 26 Relenza (zanamivir) trials. These trials involved more than 24,000 people and the findings challenge the historical assumption that neuraminidase inhibitors are effective in combating influenza. The evidence also suggests there are insufficient grounds to support the use of Tamiflu in preventing person-to-person spread of influenza. This raises further questions about the most effective way to support drug regulation and public health policy decision-making. Claims about the effectiveness of Tamiflu against complications were a key factor in decisions made by governments around the world to stockpile these drugs in case of a pandemic. The US has spent more than $1.3 billion buying a strategic reserve of antivirals, while in the UK the government has spent almost £424 million for a stockpile of about 40 million doses*.
– Compared with a placebo, taking Tamiflu led to a quicker alleviation of influenza-like symptoms of just half a day (from 7 days to 6.3 days) in adults, but the effect in children was more uncertain. There was no evidence of a reduction in hospitalisations or serious influenza complications; confirmed pneumonia, bronchitis, sinusitis or ear infection in either adults or children. Tamiflu also increased the risk of nausea and vomiting in adults by around 4 percent and in children by 5 percent. There was a reported increased risk of psychiatric events of around 1 percent when Tamiflu was used to prevent influenza. Evidence also suggests that Tamiflu prevented some people from producing sufficient numbers of their own antibodies to fight infection.
* April 2014 Cochrane Review