Twenty of this year’s more than two dozen confirmed mpox cases came after August, concentrated mostly within the Western Cape. Writing for Spotlight, Elri Voigt looks at how the virus has changed and how much of the donated vaccine is left in the country.
By 27 October, 26 cases had been confirmed in South Africa, said Dr Jacqueline Weyer, head of the Centre for Emerging Zoonotic and Parasitic Diseases at the National Institute for Communicable Diseases (NICD).
Of those, 18 are in the Western Cape, thrjee in Gauteng, two in the Eastern Cape, another two in the Free State, and one is in KwaZulu-Natal. Most of the cases, 20, have been detected in the past three months, all but one of them being in men aged 23 to 50. One case was in a woman between 35 and 44.
Seven people have been admitted to hospital, but no deaths have been reported so far this year.
Low number of cases overall
Mpox was first identified in humans in 1970, and observed mostly in central, east and west Africa. The Democratic Republic of the Congo (DRC) was particularly affected, with thousands of cases reported since 2005.
Then in 2022, the virus began to spread rapidly around the globe. Around 140 countries have reported cases since 2022, according to the WHO’s mpox dashboard, with more than 190 000 laboratory-confirmed cases reported and more than 536 deaths to date.
Overall, cases have been low in South Africa – confirmed number since 2022 sitting at 71. The NICD mpox dashboard lists 66 cases and three deaths between 2024 and 2026. In 2023, according to Weyer, there were no reported cases of mpox in the country. There were five cases in 2022, according to information on the NICD’s page on mpox.
Small outbreaks
While the number of mpox cases have been relatively low to date, the current situation can be referred to as an outbreak.
Weyer told Spotlight an “outbreak” doesn’t necessarily mean a “large number” of people are affected.
“Outbreaks may be large, small and confined, and for some conditions, a single case may be denoted as an outbreak.” In public health, she added, “an outbreak refers to the occurrence of cases of a disease in a particular place and period that warrants investigation and a public health response”.
When asked if there is a risk for a larger mpox outbreak in the country, Weyer was cautious.
“We cannot rule out the possibility of further cases, particularly while investigations are ongoing and local transmission has occurred previously,” she said.
“The risk of further spread depends on several factors, including how quickly cases are detected, the number and nature of contacts, the extent of transmission within affected networks, and the effectiveness of public health measures.
“We have the opportunity to intervene early, identify additional cases and reduce the likelihood of further spread – to remain alert without creating unnecessary alarm.”
The deal with vaccine doses
There is a limited number of donated vaccines available in South Africa. Since there are no registered vaccines against mpox or other treatment options, any jabs or treatment used will need to be supplied via a Section 21 request, which allows for medicines that are not registered in South Africa to be brought in.
Vaccines against smallpox – caused by a virus closely related to mpox – can offer some protection. There are three shots that can be used against mpox: LC16m8, MVA-BN and ACAM2000. The latter is only registered for limited use in the United States.
Last year, the Africa Centres for Disease control and Prevention (Africa CDC) donated more than 10 000 doses of the vaccine MVA-BN (brand names Imvanex and JYNNEOS) to the National Department of Health. These have been used ever since, with 2 365 doses administered between September 2025 and September 2026, health department spokesperson Foster Mohale told Spotlight.
There are 3 865 doses still available, he added, which will expire on 31 August 2027. We asked the department about the remaining 4 000 or so doses but are still awaiting reply.
When asked whether any additional mpox vaccines would be procured or donated, Mohale said: “Yes, the department is reviewing procurement options of additional … doses, dependant on the recommendation from [the] Incident Management Team and the National Advisory Group on Immunisation.”
Doses are distributed to provinces as required, depending on “disease outbreak and response”, he added.
Vaccination for mpox is recommended for people at high risk of acquiring the virus and of getting severe disease. It can also be considered as a form of post-exposure prophylaxis for people who have been in contact with someone with mpox.
An antiviral – tecovirimat – is occasionally used to treat mpox symptoms in severe cases, and there is some limited stock of the drug available in South Africa, which Mohale said was sourced through the WHO and Africa CDC’s Access and Allocation Mechanism.
There are still more than 40 containers of tecovirimat capsules available, Mohale added. But there are no plans to procure more, although this would depend on recommendation from the Incident Management Team and the National Essential Medicines List Committee. He did not say how many treatment courses are in a container.
In a 2025 National Department of Health mpox guideline document, the National Essential Medicines List Committee suggested tecovirimat be used only to treat those with severe disease who have been hospitalised.
This is because the drug has not been shown to make any significant difference in most cases of mpox. Earlier this year, results from a phase 3 study published in the New England Journal of Medicine showed that there was “no evidence that tecovirimat therapy shortened the time to clinical resolution, reduced pain, or increased viral clearance among adults with clade II mpox”.
How outbreaks have changed since 2022
At first, mpox cases in the country were traced back to international travel. Then in 2024 and 2025 we started seeing local transmission.
Most people diagnosed with the virus in 2024 reported no recent international travel history, Weyer said, noting that “the epidemiological assessment indicated that local person-to-person transmission was occurring”.
For the current situation, Weyer said local transmission is “implied”, noting that investigations are still ongoing.
“This has been established by identifying contact links between cases, and identifying the same clade and sub-lineage of the mpox virus associated with the cases to date.”
Some people who were diagnosed with mpox this year had recently been out of the country. One had been to Spain, while another had travelled to Belgium. In two other cases, international travellers came to South Africa already carrying the virus.
The clades at play
The mpox virus has two clades, clade I and clade II, with several sub-clades. Professor Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation at Stellenbosch University, explained to Spotlight previously that clades are a classification system based on the genetic similarities between different strains of a virus.
“So, what it means is that when we see a genetic change [in a virus] that’s really visible and that may have impacted it, normally we call it a different clade or genotype or variant,” he said at the time.
For now, the two mpox sub-clades driving most cases are sub-clade Ib and sub-clade IIb. This year, cases of mpox in South Africa are a mix of the two sub-clades. The mpox dashboard shows that of the 26 cases, 19 were sub-clade Ib, four were sub-clade IIb, and three cases didn’t have sub-clade information available.
In 2022, sub-clade IIb was driving the mpox outbreak, said Weyer. This changed by 2024 when a new strain of the mpox virus spread beyond the DRC. Sub-clade Ib was first identified in the DRC in 2023 and was behind a large outbreak of the illness in the country that year. This sub-clade spread from the DRC through international travel and cases of sub-clade Ib were reported across the globe by 2024.
The first case of mpox where sequencing indicated sub-clade Ib in South Africa was detected in 2025, according to the NICD dashboard. There was a total of 15 mpox cases reported that year, and sequencing information was available in all but one of the cases.
Weyer said that at the moment there is not any evidence to indicate additional mpox clades or sub-clades are circulating in the country.
How mpox is diagnosed and managed
Knowing which clade or sub-clade someone with mpox has doesn’t change how their illness is managed. Instead, it helps scientists track outbreaks.
“Understanding the genetic character of the viruses assists us in tracking outbreaks, evolution of the viruses and identifying markers which may affect diagnostic test performance and potentially vaccine efficacy,” Weyer said.
“The central priorities remain early diagnosis, appropriate clinical care, identifying and monitoring contacts, vaccination of eligible target groups, and communicating accurate information without stigmatising affected individuals or communities. The approach is the same regardless of the current genetic character of these viruses.”
Mpox is mainly spread through close contact with someone who has the virus or contact with material like bedding or clothing that has been in contact with someone with mpox. It has an incubation period of anything from five to 21 days – but usually around seven to 14 days.
In most cases, according to the mpox guideline document, symptoms can be managed at home, with rash-related pain being a particular challenge. Severe mpox cases require hospitalisation.
Someone who has mpox is considered contagious until the rash has completely gone away, and the scabs have healed.
“People who develop an unexplained rash, particularly when accompanied by fever, swollen lymph nodes or a history of possible exposure, should seek medical assessment,” Weyer advised. “They should avoid close physical contact with others while awaiting clinical guidance and testing. Mpox is preventable and early diagnosis and appropriate care are important in reducing transmission and complications.”
See more from MedicalBrief archives:
Free State records two mpox cases
Mpox surges in SA and 11 African countries
Explosive mpox outbreak batters Madagascar