The WHO has activated its highest alert level for the growing monkeypox outbreak, declaring the virus a public health emergency of international concern.

In an unprecedented move, the UN agency’s director-general decided to issue the declaration on Saturday despite a lack of consensus among experts serving on the health agency’s emergency committee.

Announcing the action, Dr Tedros Adhanom Ghebreyesus said: “We have an outbreak that has spread around the world rapidly through new modes of transmission about which we understand too little and which meets the criteria in the international health regulations.”

The rare designation means the WHO now views the outbreak as a significant enough threat to global health that a co-ordinated international response is needed to prevent the virus from spreading further and potentially escalating into a pandemic.