WHO extends mpox emergency as more transmissible clade 1a variant identified in DR Congo

Following a meeting of its mpox emergency committee yesterday, the World Health Organization (WHO) today accepted the experts’ recommendation that the situation still warrants a public health emergency of international concern (PHEIC) under the International Health Regulations.

The WHO first declared the mpox PHEIC in August 2024 amid a surge in Africa, some of which involved the spread of the novel clade 1b virus. The complex outbreaks in Africa mainly involve the spread of clade 1a and 1b viruses, with some appearance of the clade 2 virus that has spread.

WHO emergency committees typically meet every 3 months or more often as needed, depending on developments. The mpox group last met in November 2024. Today’s extension came with tweaks to its temporary recommendations for affected countries, which include those reporting sporadic travel-related cases.

Weighing in on the WHO’s extension today, an official from the Africa Centres for Disease Control and Prevention (Africa CDC) said several African nations continue to report a rise in cases, with outbreaks expanding to new countries in the region. 

Ngashi Ngongo, MD, PhD, MPH, who leads Africa CDC’s mpox incident management team, said growing armed conflict in the Democratic Republic of the Congo (DRC) is occurring in one of the main mpox hot spots, increasing the risk of spread to other provinces and countries.

Mutation makes more deadly strain more transmissible

He also noted the emergence of new variants, especially a clade 1a variant detected in the DRC that carries the APOBEC3 mutation, which enhances its transmissibility. 

Clade 1a is the older clade that has been linked to spillovers in animals and some limited human-to-human transmission in endemic areas. Clade 1a is thought to be more deadly and capable of causing more severe disease than are clade 1b or clade 2.

Ngongo said the new clade 1a variant raises significant public health concerns, due to the higher transmissibility of an mpox strain with higher morbidity. He noted that the novel clade 1b strain also carries the APOBEC3 mutation, a factor in what makes it more transmissible.

Overwhelmed treatment centers in Uganda

In other updates, Ngongo said 14 of 22 affected African countries are still in the active outbreak stage, including South Africa, which reported three new cases after more than 90 days without any. 

Growing tensions in the eastern part of the DRC pose a risk of further spread and are complicated by a US government freeze on public health funding, which has disrupted the transportation of samples in the DRC and surveillance in the DRC and Uganda.

Overall, cases in Africa have declined over the past 5 weeks, but Ngongo said the trend is likely affected by reporting delays and declines in testing coverage in the DRC. Over the past week, 12 countries reported nearly 2,000 cases, which included 42 deaths. Ngongo said South Sudan, one of most recently affected countries, reported that a recent imported case involved clade 1a, and that both 1a and 1b clades are circulating in the Republic of Congo, where cases are on the rise.

In Uganda, another hot spot, cases continue to rise and are overwhelming some treatment centers, with the country now opting for home-based care for patients who have less severe cases.

One bright spot is the launch of vaccination in the most affected area of Kinshasa, the DRC’s capital, he said. Healthcare workers vaccinated 24,400 people in just 4 days, with long lines a testament to high acceptance in the communities.