First case of clade 1 mpox confirmed outside Africa

Sweden has become the first country outside of Africa to report a case of mpox caused by the novel clade 1 variant, just one day after WHO Director-General Dr Tedros Adhanom Ghebreyesus announced 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).

Caused by an Orthopoxvirus, mpox was first detected in humans in the DRC in 1970. The disease is considered endemic to countries in central and west Africa, but a multi-country outbreak of clade 2 of the virus was declared a PHEIC in July 2022 as it spread rapidly via sexual contact across a range of countries where it had not been seen before. That PHEIC was declared over in May 2023 after a sustained decline in global cases.

Last year case numbers increased significantly, and this year’s number of reported cases has already exceeded last year’s total — with more than 15,600 cases and 537 deaths. The emergence and rapid spread of a new virus strain in DRC, clade 1b, and its detection in countries neighbouring the DRC is considered especially concerning, with over 100 laboratory-confirmed cases of clade 1b recently reported in four countries neighbouring the DRC that have not reported mpox before — Burundi, Kenya, Rwanda and Uganda.

As for the Swedish case, the infected person had recently returned from a stay in the part of Africa where there is a major outbreak of clade 1. While clade 2 is mainly spread through sexual contact, clade 1 can be spread through other contact routes — mainly to close contacts within the household — and often to children. Furthermore, clade 1 is associated with a higher risk of a more severe course of disease and higher mortality than clade 2.

“The emergence of a new clade of mpox, its rapid spread in eastern DRC, and the reporting of cases in several neighbouring countries are very worrying,” Tedros said. “On top of outbreaks of other mpox clades in DRC and other countries in Africa, it’s clear that a coordinated international response is needed to stop these outbreaks and save lives.”

Last week, Tedros triggered the process for Emergency Use Listing for mpox vaccines, which will accelerate vaccine access for lower-income countries which have not yet issued their own national regulatory approval. Emergency Use Listing also enables partners including Gavi and UNICEF to procure vaccines for distribution.

WHO is working with countries and vaccine manufacturers on potential vaccine donations, and coordinating with partners through the interim Medical Countermeasures Network to facilitate equitable access to vaccines, therapeutics, diagnostics and other tools. WHO anticipates an immediate funding requirement of an initial US$15 million to support surveillance, preparedness and response activities.

“The current upsurge of mpox in parts of Africa, along with the spread of a new sexually transmissible strain of the monkeypox virus, is an emergency not only for Africa, but for the entire globe,” said Professor Dimie Ogoina, chair of the committee that recommended the PHEIC designation. “Mpox, originating in Africa, was neglected there, and later caused a global outbreak in 2022. It is time to act decisively to prevent history from repeating itself.”

Image credit: iStock.com/Berkay Ataseven