#18,175
While we are watching the evolution and (so far, limited) spread of a far more dangerous Clade Ib Mpox virus in the DRC, the milder clade IIb virus - which began its world tour in 2022 - continues to cause sporadic outbreaks around the globe (see CBS News S.F. officials monitor rise in domestic mpox cases as global outbreak spreads).
As of 26 June 2024, the Republic of South Africa had notified the WHO of 16 confirmed cases of mpox, including three deaths, during 2024. These cases were confirmed from 8 May 2024 to 23 June 2024 and 15 of the 16 patients were hospitalized. Prior to this, at the height of the multi-country outbreak, the Republic of South Africa had reported five mpox cases and no deaths from June 2022 to August 2022. The new reports represent the first mpox cases detected in the country since August 2022, and the first deaths altogether.
The fatality rate of clade IIb in central Africa has normally been in the low single digits, and internationally less than 1%, while in this limited cohort, it was pushing nearly 20%. The difference appears to be due to the high rate of HIV in South Africa.
The WHO explained:
Eleven cases have been reported to be persons living with HIV (PLHIV), with either unmanaged or only recently diagnosed HIV infection. There have been three deaths among the 16 confirmed cases, resulting in a case fatality ratio (CFR) of 19%, much higher than the clade IIb mpox global CFR which was 0.2% overall as at the end of May 2024. This disproportionate burden of HIV, severe mpox disease, and deaths suggests that MPXV is likely circulating in the community and has reached the most susceptible individuals. I
Yesterday the WHO published a DON (Disease Outbreak News) report on the Mpox situation in South Africa (see below), including an updated risk assessment.
9 July 2024
Situation at a glance
The International Health Regulations (IHR) National Focal Point (NFP) of the Republic of South Africa notified WHO of 20 confirmed mpox cases between 8 May and 2 July 2024, including three deaths (case fatality ratio (CFR) of 15%). These cases were reported in three of nine provinces: Gauteng (10 cases; 1 death), Western Cape (1 case), and KwaZulu-Natal (9 cases; 2 deaths).These are the first cases of mpox reported in South Africa since 2022 when the country had reported five cases, none of which were severe, and no deaths. The persons affected are men aged between 17 and 43 years old, and of the first 16 cases, 11 self-identified as men who have sex with men (MSM). At least 15 cases are living with HIV with unmanaged or only recently diagnosed HIV infection, and have advanced HIV disease (AHD), and one case has diabetes. The type of exposure contact reported by cases is sexual contact.Eighteen of the patients required hospitalization. Several response measures have been put in place by national health authorities with the support of WHO. The sudden appearance of these cases none of whom reported any history of international travel, the extremely high HIV prevalence among confirmed cases, and the high case-fatality ratio suggest that the confirmed cases are only a small proportion of all cases that might have occurred, and that community transmission is ongoing. The risk to human health for the general public remains low in the country.The risk for gay men, bisexual men, other men who have sex with men, trans and gender-diverse people, and sex workers is moderate. There is potential for increased health impact should wider dissemination among these and other vulnerable groups in South Africa and neighbouring countries continue. This event emphasizes that the global mpox outbreak linked to clade IIb monkeypox virus (MPXV) is still ongoing, and the risk of cross-border and international spread persists in all WHO regions.
Description of the situation
The IHR NFP of the Republic of South Africa notified WHO of 20 confirmed mpox (monkeypox) cases between 8 May and 2 July 2024, including three deaths (CFR 15%). These cases were reported in three of nine provinces: Gauteng (10 cases; 1 death), Western Cape (1 case), and KwaZulu-Natal (9 cases; 2 deaths).
The cases are all male, aged between 17 and 43 years, and almost all self-identified as men who have sex with men (MSM). Most are persons living with HIV, with unmanaged or only recently diagnosed HIV infection and advanced HIV disease (AHD), and one has diabetes. All cases were symptomatic, with extensive skin lesions and 18 required hospitalization. None of the confirmed cases reported a history of international travel and none reported attending high-risk social gatherings. The type of exposure reported by cases is sexual contact.
For the first 16 cases overall, 44 contacts were identified in KwaZulu-Natal, 39 contacts in Western Cape, and 55 in Gauteng province. While three of the four initial cases in KwaZulu-Natal were epidemiologically linked through contact tracing, at least the initial seven in Gauteng province were not found to be epidemiologically linked, suggesting community transmission is underway. Individual contact tracing for recent cases is ongoing. In addition, limited information suggests that some affected persons have attended and been exposed to mpox at parties or clubs where sexual activity occurs.
Genomic sequencing, available for five confirmed cases has identified sub-clade IIb MPXV, the clade linked to the multi-country mpox outbreak.
During the ongoing 2022-2024 multi-country outbreak, five mpox cases had previously been confirmed in South Africa, during the peak in June-August 2022, and all had reported travel abroad. None of the cases were severe. No cases were reported in 2023.(SNIP)
WHO risk assessment
The sudden appearance of unlinked cases of mpox in South Africa without a history of international travel, the high HIV prevalence among confirmed cases, and the high case fatality ratio suggest that community transmission is underway, and the cases detected to date represent a small proportion of all mpox cases that might be occurring in the community; it is unknown how long the virus may have been circulating. This may in part be due to the lack of early clinical recognition of an infection with which South Africa previously gained little experience during the ongoing global outbreak, potential pauci-symptomatic manifestation of the disease, or delays in care-seeking behaviour due to limited access to care or fear of stigma.
At present, most of the transmission in the initial cases is linked to recent sexual contacts among men, similar to the spread in newly affected countries during the 2022-2024 multi-country outbreak. For most confirmed cases, no epidemiological link has been established, possibly due in part to incomplete contact identification. There is potential for increased health impact should wider dissemination continue in vulnerable groups in South Africa or neighbouring countries.This suggests that undetected community transmission is occurring and that further cases can be expected as surveillance is strengthened. The current risk to human health for the general public remains low in the country.
The risk for gay men, bisexual men, other men who have sex with men, trans and gender diverse people, and sex workers is moderate, as currently assessed for the global outbreak. The higher risk assessment is consistent with ongoing transmission among recognized risk groups due mainly to exposure through sexual contact, and the higher prevalence of undetected or uncontrolled HIV infection in the country which also puts people at risk of severe disease. There is potential for increased health impact should wider dissemination continue in vulnerable groups in South Africa or neighbouring countries. Data from ongoing mpox outbreaks show that the risk of severe disease and death is higher among children, immunocompromised individuals including persons with poorly controlled HIV, and pregnant women.
The most recent Joint United Nations Programme on HIV/AIDS (UNAIDS) data estimate HIV prevalence among men who have sex with men in South Africa to be around 30%, only 44% of whom are on antiretroviral therapy. This makes this group extremely vulnerable to severe mpox disease and death. There is also a hazard to health workers if they are not appropriately using personal protective equipment (PPE) when caring for patients with mpox.
Prior to 2022, the CFR for clade II MPXV in West Africa was estimated to be 3.6% (95% CI: 1.7%, 6.8%). Case fatality in the ongoing multi-country outbreak (0.02%) is the lowest recorded for MPXV clade II. In contrast, the CFR among cases reported in South Africa in 2024 is extremely high (15%), as most detected cases are among persons who are immunocompromised with uncontrolled HIV and other co-morbidities. Persons with less severe mpox are less likely to recognize the condition or seek diagnosis and care; therefore, such cases may remain undetected and unreported.
Vaccination with mpox vaccines has been shown to be effective against mpox. The last case of smallpox in South Africa was report ed in 1972, and smallpox vaccination stopped shortly after the global eradication of the disease in 1980. Thus, any immunity from prior smallpox vaccination (which is cross-protective for mpox) will at best now only be present in some persons over the age of 44 years. The median age of mpox cases in the current global outbreak is 34 years (IQR: 29 - 41) and within South Africa, reported cases are aged between 17-43 years.The limited awareness of mpox and lack of knowledge about practices for prevention among health workers and among key populations such as sex workers or men who have sex with men in the country exacerbates their risk for mpox. Anyone suffering from disfiguring skin conditions, including mpox, may experience fear and stigma, which can be further compounded for key populations.
There is concern that the mpox outbreak in South Africa will continue to evolve given:
- The high likelihood of under-detection and under-reporting of local transmission, given that reported cases have to date almost exclusively affected the most vulnerable.
- Currently, all detected cases have presented with severe disease and extensive skin lesions, which could lead to more viral transmission and risks poor outcomes for the patients.
- While the government and partners are mobilized to introduce treatment for affected patients and vaccines for people at risk, these countermeasures are not yet widely available in the country.
- Public awareness of mpox and information about modes of transmission or possible amplifying events or risk of exposure in sex-on-premises venues remains limited in South Africa.
- Concurrent outbreaks of mpox are occurring in Africa and elsewhere, increasing the risk of further transmission.
Although the WHO discontinued their PHEIC (Public Health Emergency of International Concern) declaration after only 10 months in May of 2023, the Mpox clade IIb continues to spread - often under the radar - around the globe.
As it spreads from host-to-host, additional evolutionary changes seem likely (see Evolution of monkeypox virus from 2017 to 2022: In the light of point mutations).
Since the eradication of smallpox in the 1970s, there is a general feeling that poxviruses are a thing of the past, a relic of the 20th century. But as our collective immunity from the smallpox vaccine - which was discontinued in the late 1970s - dwindles, there are increased opportunities for pox viruses to make a comeback.
Some blogs on less common orthopoxvirus threats, include:
Alaska Health Department Announces A Fatal Alaskapox Infection
A Newly Discovered Poxvirus Detected In Reindeer in Sweden & Norway
EID Journal: Novel Poxvirus in Proliferative Lesions of Wild Rodents in East-Central Texas, USA
A Novel Zoonotic Orthopoxvirus Resurfaces In Alaska
