SA’s HIV burden a concern as new mpox strain spreads in DRC – but much still unknown

9 Sep 2024

The African Centre for Disease Control and World Health Organization have raised the alarm following a drastic uptick in mpox cases. This surge is being driven by a new strain of the virus. Elri Voigt reports about what we know so far and the potential implications for South Africa.

Mpox, a viral illness first identified in Africa in 1970, made headlines in 2022 when it spread across the globe for the first time. Since then, the outbreak has evolved, with multiple strains of the virus circulating in different countries. A new strain, known as clade Ib, first discovered in the Democratic of the Republic of Congo (DRC), is responsible for much of the most recent surge in mpox cases.

These recent developments are complex, and the situation is likely to change. This was the common theme of a special session on the mpox outbreak during the World Health Organization (WHO) Regional Committee for Africa meeting at the end of August. This session took place two weeks after the WHO declared the outbreak to be a Public Health Emergency of International Concern.

“We don’t have one outbreak. We have multiple outbreaks in one,” Dr Jean Kaseya, the Director General of the African Centre for Disease Control, remarked.

These outbreaks are caused by different clades of the mpox virus. Clades are a classification system based on the genetic similarities between different strains of a virus, explained Professor Tulio de Oliveira, the director of the Centre for Epidemic Response and Innovation at Stellenbosch University. “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.

This is similar to classifying different strains of SARS-CoV-2 as variants, Dr Duduzile Ndwandwe, a molecular biologist working for Cochrane South Africa, an intramural research unit within the South African Medical Research Council, told Spotlight.

She said that the different mpox clades and sub-clades had mutated so they had genetic differences, but still fell under the umbrella of mpox.

“In a nutshell… it’s just talking about the differences in the genome sequence of the virus, how many mutations (it has) or how big the mutations are in that virus’s strain of mpox,” she said.

‘Jump in evolution’

Dr Aida Sivro, senior scientist at the Centre for the Aids Programme of Research in South Africa, in 2022 told Spotlight that there were two clades of the mpox virus, which were then referred to as the Central African Clade (clade I) and the West African Clade (clade II).

Since then, clade I went through a big jump in evolution and a sub-clade emerged in the DRC, now called clade Ib, De Oliveira told Spotlight. The previous outbreak in 2022 was mostly driven by another sub-clade called clade IIb.

To further complicate matters, there’s a third strain of the virus also circulating – clade Ia.

At the moment, the DRC accounts for about 90% of mpox cases in the African Region, according to Dr Fiona Braka, the Emergency Response Manager for WHO’s Afro region. She said that right now the situation was not fully understood because a lack of diagnostics and testing capabilities was limiting understanding of the true burden of disease.

What we do know, she said, was that there were two distinct outbreaks in the DRC. Based on the information currently available, clade Ia was circulating in regions in the country where mpox was considered endemic and affected mostly children. Clade Ib was spreading mostly among adults in the eastern provinces of South Kivu and North Kivu.

The clade Ib strain had since spread from the DRC to neighbouring countries Burundi, Rwanda, Uganda and Kenya, according to Braka. Sweden and Thailand had also identified one case each.

As of 1 September, the WHO reported that there had been 3,751 confirmed cases of mpox and 32 deaths across 14 countries in Africa in 2024 alone. But there were many more suspected cases of mpox that had not been tested.

Implications for South Africa

De Oliveira said that at this point, South Africa shouldn’t be overly concerned about mpox, but it should be alert. The best way to do this was to make sure the public knew what the symptoms were so they could present for diagnosis and treatment if they suspected they had the virus.

In a similar vein, Ndwandwe said the public shouldn’t panic, but we as a country needed to remain vigilant. She added that because clade Ib was spreading on the African continent, there was a risk of it spreading to South Africa through cross-border travel, making it a public health concern.

This year, 24 cases of mpox have been reported in South Africa. Three people have died, while 19 have recovered. Two people are still considered to have active disease, with the most recent case identified in early August. But this doesn’t necessarily mean there aren’t more cases of mpox in the country.

“What we do suspect is that we may have milder cases that are actually not reported,” Nevashan Govender, the operation manager of the Emergency Operations Center at the National Institute for Communicable Diseases, told Spotlight.

He said that so far, all the cases in the country had been caused by clade IIb, and no cases of clade Ib had been identified.

A polymerase-chain-reaction test was the gold standard test used to determine whether someone had mpox. But genome sequencing would need to be done to identify what clade they had.

Lots of unknowns around new strain

At the moment, there were a lot of unknowns around clade Ib.

What was of concern, according to Braka, was the severity of disease seen especially in people who were immunocompromised, and in pregnant women and children. Ndwandwe added to this and said there was a concern that clade Ib had higher fatality rates than clade IIb.

De Oliveira cautioned against jumping to conclusions about the severity of this new clade without sufficient data. He said we didn’t know for sure yet if clade Ib was causing more severe disease than IIb. What we did know from mpox in general, he said, was that when someone was immunocompromised in some way, they tended to develop more severe symptoms.

Govender echoed De Oliveira’s caution that we didn’t yet know enough about clade Ib to say definitively if it was, for example, more transmissible than other clades

“It’s not to say that it isn’t (more transmissible), but there is just not a lot of evidence stating that it is absolutely true… There’s a lot of knowledge and information gaps,” he said.

The National Institute for Communicable Diseases in a recent update also stressed that there were a lot of unknowns about this new strain. It added: “South Africa continues to prioritise enhanced surveillance and raising awareness for mpox.”

The state of vaccines and treatment for mpox

Spotlight reported previously that the smallpox vaccine, which hasn’t been routinely administered in South Africa since the 1980s when smallpox was eradicated, is thought to offer some degree of protection against mpox. However, it’s difficult to predict just how much protection the smallpox vaccine would provide.

There were currently three vaccines against mpox that had been approved in some countries, a spokesperson from the vaccine alliance Gavi told Spotlight. These were LC16m8, Jynneos and Acam2000.

LC16m8 was a third-generation small pox vaccine manufactured by KM Biologics. According to the WHO, from 2022 it had mainly been used in Japan.

The Jynneos vaccine was a third-generation smallpox vaccine, manufactured by Bavarian Nordic, Ndwandwe said, and it was used during the outbreak in 2022. She added that this vaccine was considered the preferred option due to its safety profile and targeted protection against mpox.

Acam2000 was a second-generation vaccine for smallpox and was manufactured by Emergent BioSolutions. But it was only approved by the FDA for use in those at high risk for mpox at the end of August this year. It was not widely used during the 2022 outbreak but was available in some places under a compassionate use protocol (a means of providing medicines or vaccines that have not yet been registered).

In 2022, the Centre for Disease Control recommended that Jynneos be used as the primary vaccine against mpox because it was associated with fewer side effects than Acam2000.

While these vaccines exist, it doesn’t mean everyone can access them easily. Countries on the African continent have so far relied on vaccine donations facilitated by the WHO, with an initial 10,000 doses expected to arrive in Africa sometime this month.

Both vaccine manufacturers had submitted proposals to the WHO for emergency use listing, according to WHO Director-General Dr Tedros Adhanom Ghebreyesus. He added this wouldl allow Unicef and the vaccine alliance Gavi to buy the vaccines to supply to countries that had’t issued their own national regulatory approval yet.

The treatment options for mpox are also limited. According to this WHO factsheet on mpox, some antivirals have received emergency use authorisation in some countries and are being evaluated in clinical trials. However, so far there is no proven effective antiviral treatment for mpox.

Tecovirimat, which was approved to treat smallpox, is one of these antivirals being evaluated. According to the African Centre for Disease Control, studies in animals have shown the antiviral might help treat mpox, but it is still considered an investigational drug for mpox. The drug has been used in some cases of severe mpox.

When asked about this, Ndwandwe agreed that more research needed to be conducted to fully understand the evidence around using Tecovirimat.

“But what we know now is that it was authorised for compassionate use, and there is some benefit to using that treatment, given that there isn't any other (treatment),” she said.

Mpox vaccine and treatment availability in South Africa

According to De Oliveira, a small batch of vaccines against mpox and an antiviral drug were made available to South Africa through donations during the outbreak earlier this year.

But the country would need more vaccines if cases increased to protect those at risk for severe disease.

At the moment, South Africa does not have access to any mpox vaccines and has asked for a donation of 40,000 vaccine doses, Foster Mohale, the spokesperson for the health department, told Spotlight. The country has requested the Jynneos vaccine, based on the recommendation by the National Advisory Group on Immunisation.

Health Minister Dr Aaron Motsoaledi told delegates during a WHO session on mpox that five of South Africa’s 24 mpox patients had been given tecovirimat. The drug had not been registered by the South African Health Products Regulatory Authority, but had been made available to these patients under a Section21 release and was supplied by a WHO donor programme. Section 21 licenses allowed for medicines that were not registered in South Africa to be brought into the country.

He also requested the WHO’s assistance in procuring the 40,000 vaccine doses to vaccinate high-risk groups if mpox cases increase.

When asked if the department would be entirely reliant on donations of mpox vaccines or would seek to procure its own if cases increased, Mohale said it depended.

“South Africa has been in communication with the vaccine manufacturer Bavarian Nordic, and will consider procurement if needed,” he said.

Because there is a shortage of mpox vaccines and treatment and uncertainty about the sustainability of donated supplies, Ndwandwe said: “Our best defence at this point in time is to prevent the spread of mpox cases as much as possible and detect the cases as they start, early on.”

Symptoms of Mpox

Govender said the National Institute for Communicable Diseases was urging people not to panic but to stay informed on the signs and symptoms of mpox using some of the accurate information available from either the National Department of Health or the institute.

“The first line of defence for any public health emergency and outbreak comes from when people take the initiative to protect themselves,” he said.

Mpox, which is spread by close contact, either household or sexual contact with someone who has the virus, could initially manifest in flu-like symptoms or the characteristic mpox rash. These include a fever, sore throat, muscle aches, headaches and swollen lymph nodes, according to the WHO factsheet on mpox. The rash starts flat and then becomes a blister filled with fluid, which eventually dries and falls off. The rash can occur on someone’s palms or soles of their feet, face, mouth and throat, and sometimes the genital areas.

Children, pregnant women and those who are immunocompromised are most at risk for developing severe disease or dying, the factsheet stated. This includes people living with HIV whose viral load is not well controlled.

Mpox was a virus, and as with all viral infections it was the immune system that fought it off, Ndwandwe said. However, if someone was immunocompromised,and had a weakened immune system, there was a greater chance that the mpox virus would overtake their immune system and cause severe disease.

This was one of the reasons why we would be concerned about the disease in South Africa, Professor Helen Rees, the co-chairperson of the Incident Management Team on mpox, previously told eNCA.

“We have many people living with HIV in the country, many of whom are on antiretroviral therapy, their immune system is good. But we have many others who don’t know what their status is and might be vulnerable to severe mpox,” she said. DM

This article was first published by Spotlight – health journalism in the public interest. Sign up to the Spotlight newsletter.

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