Latest mpox data in Africa: More cases registered in 2024 than in past two years

A new variant of mpox (formerly known as monkeypox) has now been recorded in several African countries after spreading from the Democratic Republic of Congo (DRC). The Africa Centers for Disease Control and Prevention released new figures Sunday that provide a clearer picture of where the virus is spreading and how fast.

So far in 2024, more than 18,000 suspected or confirmed cases of mpox have been recorded on the African continent. This is more than all the cases recorded in 2023 and 2022, when in July of that year, the WHO declared a public health emergency. The rise in cases is due to the fact that the new variant appears to spread more easily and has crossed into more countries.

There are at least two genetic clades (variants) of the mpox virus in Africa, which are known as variant I and variant II. The global outbreak that began in 2022 was caused by variant II, which is endemic in some West African countries. At that time, most infections were reported outside of West Africa, with the United States the hardest hit country. Variant I, which has been shown to be more easily transmitted, is widespread in Central Africa, particularly in the DRC, where there has been an active variant I outbreak since November 2023.

In June this year, a new subvariant of clade I, renamed variant Ib, was detected in the DRC. It sparked a second outbreak, in addition to the one that is largely caused by subvariant Ia. In other words, the Central African country — where 80% of the population lives in extreme poverty — is being hit by two outbreaks simultaneously.

The latest outbreak is the one that has set off alarm bells. The first available data indicate that this version of the virus is transmitted sexually (like the previous one) but also by very close physical contact (mouth to mouth or mouth to skin). What’s more, it is affecting more of the adult population, while infections by clade Ia occurred mainly in children.

The virus has been detected in Goma, a city that is home to two million inhabitants that borders Rwanda. Until the middle of 2024, most cases had been registered among minors living in remote villages, as reported by the journal Science.

Throughout the month of July, the Democratic Republic of the Congo has recorded almost all mpox (in all its variants) cases on the continent. In August, the country continued to account for the majority of cases (85%), but mpox was also detected in countries which had not previously recorded any cases. The following graph shows the weekly cases and a two-week average, which is a useful way for observing the trend without having to take into account possible delays in notification. According to the data, 1,500 new cases have been recorded each week since the end of July.

Between July 28 and August 2, cases were identified in Burundi, Rwanda, Kenya, Ivory Coast and Uganda. Analysis of patient samples in Uganda and Kenya has identified the new subvariant of the virus. The patients infected had travelled to the DRC. Ib was also been identified this week in Rwanda.

But the number of infections has grown the most in Burundi, a country that had not reported any new cases until the end of July. In the last month, the number of cases has gone from three to 400 and the presence of the new sub-variant has been confirmed. In the past week, when the WHO declared a state of emergency, no cases of the new variant have been recorded in other African countries.

As of Sunday, the virus has caused at least 541 deaths across the continent (535 of them in the Democratic Republic of Congo). The following graph shows that there were no more than 20 weekly deaths until the end of July, when they jumped to more than 50, in line with the increase in cases.

To date, there is still little certainty about whether the modes of transmission and severity of the clade I subvariants are different. In Africa, data indicate that by mid-August, nearly 3% of those infected had died, although this figure is somewhat higher in some countries and exceeds 11% in South Africa, where it is closely related to the fact that a large proportion of the patients infected had other serious illnesses such as HIV. The new subvariant of the virus also appears to cause more severe symptoms and to be more fatal among children.

Throughout 2022 and 2023, when the new variant was not yet known, mpox caused the death of less than 1% of those infected (208 people died). It should be noted that surveillance systems are weaker in Africa, so it is too early to know whether the apparent difference in lethality is real or not.

Last weekend, the European Centre for Disease Control and Prevention said the possibility of sustained transmission in Europe was “very low,” thanks to the speed of diagnosis and control measures such as vaccinations. The equivalent body in the United States issued a similar verdict.

Experts, however, are concerned that the new variant could become the most common variant in other African countries, where malnutrition and other pre-existing diseases could make it an even greater danger.

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