Sweden becomes first country outside of Africa to report deadly mpox strain clade I

A growing mpox crisis is unfolding globally as a more lethal strain of the virus continues to spread rapidly across Africa. The African Centers for Disease Control and Prevention (Africa CDC) has declared the outbreak a public health emergency, while the situation has escalated with the detection of mpox in wastewater within the United States.

According to an article by US publication Newsweek, detection remains extremely low, with only three sites reporting positive results: two in California and one in Illinois. Detection rates remained low within these sites, with only a small percentage of samples testing positive during this time. 

The cases detected in the US were all consistent with the virus’s original strain from the 2022 outbreak, known as clade II. The more deadly form of the virus, known as clade I, which is currently circulating in the Democratic Republic of the Congo and neighbouring countries, has not been detected in the US.

Meanwhile, on August 15, 2024, the World Health Organization reported that Sweden was the first country outside of Africa to report a case of the mpox Clade 1 variant, which is thought to be driving the latest outbreak.

Outbreaks are caused by different mpox viruses known as clades, with the clade 1 strain circulating in the DRC for many years. The emergence of a new offshoot, clade 1b, and its rapid spread, including into neighbouring countries, was one of the primary reasons why WHO declared mpox a public health emergency of international concern (PHEIC).

More than 2,100 laboratory-confirmed cases of the disease, as well as 13 deaths, have been reported this year in the DRC and 11 other countries: Burundi, Cameroon, Central African Republic, Congo, Côte d'Ivoire, Kenya, Liberia, Nigeria, Rwanda, South Africa, and Uganda. This compares to 1,145 confirmed cases and seven deaths in 11 countries across 2023.

WHO said in a statement that it has also started the process of obtaining Emergency Use Listing (EUL) for mpox vaccines, which will speed up access for low-income countries that have not yet received national regulatory approval.