Poliovirus that infected a Chinese child in 2014 may have leaked from a lab, samples destined for destruction at a Paris institute trigger a virological “detective story”.

WHO Director-General Dr Tedros Adhanom Ghebreyesus has determined that the upsurge of mpox in the Democratic Republic of the Congo (DRC) and a growing number of countries in Africa constitutes a public health emergency of international concern (PHEIC) under the International Health Regulations (2005) (IHR).