'Sustained transmission' of monkeypox risks vulnerable groups such as pregnant women, children and the immunocompromised, warns WHO

The World Health Organization has warned "sustained transmission" of monkeypox worldwide could see the virus begin to move into high-risk groups, like pregnant women, children and immunocompromised people.

It said on Wednesday that it is investigating reports of infected children, including two cases in the UK, as well as following up reports in Spain and France.

None of the cases in children have been severe.

Monkeypox has now been identified in more than 50 countries outside of Africa - where the viral disease is endemic - with one death confirmed and cases exceeding 3,400 since the outbreak was first reported in May.

Cases are also rising in those countries, said the WHO, calling for testing to be ramped up.

"I'm concerned about sustained transmission because it would suggest the virus (is) establishing itself and it could move into high-risk groups including children, the immunocompromised and pregnant women," said WHO director-general Tedros Adhanom Ghebreyesus.

The WHO has already provided detailed guidance on the outbreak, and earlier this month warned of a "rapidly evolving event" which will spread more widely if action isn't taken.

But at the weekend it decided the outbreak is not yet a global health emergency - its highest level of alert.

Speaking then, Dr Tedros Ghebreyesus said he still remained "deeply concerned" about the virus's "evolving health threat" which he said he would be following "extremely closely".

The majority of cases are still being seen among men who have sex with men. It is not yet clear whether that is because the virus is spreading among social networks within that group, or because those individuals are more likely to be aware and proactive about their sexual health.

But because monkeypox can be spread through any form of close physical contact, the assumption is that as cases continue to grow, monkeypox will spread more widely, if it has not already.

There were 1,076 confirmed cases in the UK as of 28 June, according to the latest figures released by the UK Health Security Agency (UKHSA).

The WHO has also said it is working on a mechanism to distribute vaccines more equitably, after countries including Britain and the US suggested they are willing to share their stockpiled smallpox vaccines, which also protect against monkeypox.

Monkeypox does not spread nearly as easily as COVID and there are vaccines and treatments available, unlike for coronavirus when it emerged.