The US Department of Health and Human Services (HHS) announces a new review process for certain gain-of-function (GOF) experiments on the avian influenza A (H7N9) virus, some of which are proposed this week by influenza scientists (R. A. M. Fouchier et al. Nature 500, 150–151; 2013).

Specifically, before being undertaken using HHS funds, any experiments that are reasonably anticipated to generate H7N9 viruses with increased transmissibility between mammals by respiratory droplets will undergo an additional level of review by the HHS.

The HHS review will consider the acceptability of these experiments in light of potential scientific and public-health benefits as well as biosafety and biosecurity risks, and will identify any additional risk-mitigation measures needed. The review will be carried out by a standing multidisciplinary panel of federal experts with backgrounds in public health, medicine, security, science policy, global health, risk assessment, US law and ethics. This approach, similar to that for certain H5N1 influenza virus experiments (see go.nature.com/vpmplf), allows the HHS to focus special oversight efforts on experiments of concern while allowing routine characterization and other fundamental research to proceed rapidly, thereby enabling a robust public-health response.

GOF studies can provide important insights into how the A(H7N9) virus adapts to mammalian hosts, causes disease and spreads to other hosts, but they may also pose biosafety and biosecurity risks. To ensure that research involving H7N9 virus is conducted safely and securely, the US Centers for Disease Control and Prevention recently re-examined the requisite biosafety conditions for conducting experiments involving H7N9 and, in June 2013, issued interim risk-assessment and biosafety-level recommendations (see go.nature.com/gknn9a).