Public Health England (PHE) has instructed doctors to prescribe antivirals for patients with influenza who are severely unwell or members of at-risk groups and not to be swayed by data showing that these drugs may not be effective.
In a letter issued ahead of the 2014–2015 flu season, PHE cites evidence that antivirals can substantially reduce the risk of death in patients admitted to hospital with flu.
In April 2014, a Cochrane review
concluded that the antivirals zanamivir and oseltamivir — both neuraminidase inhibitors — were not very effective at treating flu. Public health officials fear that this conclusion might deter doctors from prescribing the drugs to patients who need them and so they highlight that the Cochrane review did not consider the “substantial volume” of observational data and that the patients included in the trials were otherwise healthy.
One of the observational meta-analyses
cited by PHE, which included 29,234 patients, concluded that in those who were hospitalised with flu, there was a 25% reduction in risk of death when patients were treated with neuraminidase inhibitors. This increased to a 50% reduction in risk of death when treatment was initiated in the first two days of illness.
“It is essential that physicians treating severely unwell patients in any setting are not deterred from prescribing what may be lifesaving drugs as a result of confusion over efficacy in this situation; this is especially true for patients hospitalised with proven or suspected flu,” says Paul Cosford, director for health protection and medical director at PHE.
 Jefferson T, Jones MA, Doshi P, et al. Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children. Cochrane Database of Systematic Reviews 2014, Issue 4. Art. No.: CD008965. DOI: 10.1002/14651858.CD008965.pub4
 Muthuri SG, Venkatesan S, Myles PR, et al. Effectiveness of neuraminidase inhibitors in reducing mortality in patients admitted to hospital with influenza A H1N1pdm09 virus infection: a meta-analysis of individual participant data. The Lancet Respiratory Medicine, Volume 2, Issue 5, Pages 395 - 404, May 2014. doi:10.1016/S2213-2600(14)70041-4