Africa will need about 10-million doses of the mpox vaccine to fight an upsurge of the disease, says Jean Kaseya, head of the Africa Centres for Disease Control and Prevention.

The outbreak has been declared a public health emergency of international concern to enable the mobilisation of resources to affected countries.

A more severe strain of the virus, known as clade I, is spreading rapidly in the Democratic Republic of Congo. More than 17,000 suspected cases of mpox (2,800 confirmed) and 541 deaths have been reported in the DRC, where mpox is endemic. Since July cases of clade I have been detected in Burundi, Kenya, Rwanda and Uganda, countries that have not reported cases of mpox before.

Two substrains of clade I have been detected in the DRC. Clade 1a, which has been around since the 1980s, primarily affects children. Clade 1b emerged only around September 2023. It primarily affects adults and is spreading rapidly, according to the World Health Organization.

South Africa, which has reported 24 cases of mpox and three deaths, has the clade II strain of the virus. The international outbreak of mpox in 2022-2023 was caused by the clade II strain.