#18,258
For the better part of a year we've been watching the evolution and spread of a new, and reportedly more dangerous clade Ib Mpox virus in the DRC, and more recently its spillover (along with the older clade I & clade II virus) into neighboring countries (see More African Nations Reporting Mpox - Africa CDC Mpox Update (Jul 30th)).Last week the WHO declared a Public Health Emergency of International Concern (PHEIC), and since then at least two non-African nations (Sweden & Thailand) have confirmed clade Ib cases. It is likely that other cases are already spreading under the radar around the globe.
Complicating matters, surveillance and testing are extremely limited in the most affected countries in Africa, making tracking the progress of this virus very difficult. As the WHO map above illustrates, there is a complicated mix of clades involved.
While clade IIb - which began its world tour in early 2022 - is believed to be the mildest, we've seen varying assessments on the severity of clade I and Ib. Some reports have suggested up to a 10% fatality rate, while others have come in far lower (1%-3%).
Anecdotal reports, however, suggest clade Ib is more transmissible.
Since the virus continues to evolve, with new zoonotic spillovers continuing to occur, some of these variants (even within the same clade) may be more virulent than others. But it is also true that many cases go undetected (or untested), making good estimates exceedingly hard to come by.
The threat from Mpox is nothing new, of course.
In 2013, the DRC reported a 600% increase in cases over both 2011, and 2012 (see EID Journal: Extended H-2-H Transmission during a Monkeypox Outbreak) and in 2014, in Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo, the authors warned on its ability to mutate into a more human-transmissible virus.
Yesterday the WHO released an updated DON (Disease Outbreak News) report on the Mpox outbreak in Africa, and unveiled a new Mpox surveillance dashboard.
You'll note that the numbers here are of laboratory confirmed cases, and are therefore far lower than previous reports of confirmed & suspected cases, and undoubtedly seriously under-represents what is going on in these countries.
Due to their length, and the fact that the numbers presented are transitory at best, I've only included some brief excerpts. Follow the links to read both reports in their entirety. I'll have a postscript after the break.
Mpox – African Region
22 August 2024
Situation at a glance
On 14 August 2024, the WHO Director-General determined that the upsurge of mpox in the Democratic Republic of the Congo and a growing number of countries in Africa constitutes a Public Health Emergency of International Concern (PHEIC) under the International Health Regulations (2005) (IHR), the highest level of alarm under the IHR. Here we describe the latest countries in the region newly reporting cases since the start of the multi-country outbreak in 2022.The clade Ib MPXV outbreak, which began in September 2023 in the Democratic Republic of the Congo, is having an increasing number of cases in the country and also expanding to neighbouring countries. Burundi, Kenya, Rwanda and Uganda have each reported their first mpox cases. Several of these cases have travel links to eastern parts of the Democratic Republic of the Congo and each of these countries has identified clade Ib monkeypox virus (MPXV). Based on available epidemiological data, this clade has been spreading rapidly among adults through close physical contact, including sexual contact identified within networks of sex workers and their clients.As the virus spreads further, the affected groups are changing, with the virus also taking hold within households and other settings. Additionally, Cote d’Ivoire is reporting cases of clade II mpox for the first time since the start of the multi-country outbreak in 2022.
(SNIP)
WHO risk assessment
The current expansion of mpox in the African continent is unprecedented. At least four countries have identified cases for the first time and others, such as Côte d’Ivoire, are reporting re-emerging outbreaks. The modes of transmission in these countries are not fully described yet and are likely to include exclusive human-to-human transmission.
Clade I mpox is being identified for the first time outside of the countries that had been previously affected. Initial transmission in the newly affected countries in East Africa and beyond has been linked to travel to or from the Democratic Republic of Congo, but the expansion of the outbreak in Burundi suggests that in some settings, there may already be sustained community transmission. Epidemiological links between confirmed cases are not always known, therefore, multiple transmission chains might be ongoing in the different countries, and more undetected cases in the community are likely. Based on available epidemiological data, this clade has been spreading rapidly among adults through close physical contact, including sexual contact identified within networks of sex workers and their clients. As the virus spreads further, the affected groups are changing, with the virus also taking hold within households and other settings.
In areas or congregate settings with high population density as well in high-risk sexual networks, transmission could lead to explosive outbreaks, further compounded by population movements or insecurity. Conversely, the virus can also spread silently along commercial travel routes as in some cases symptoms may be less severe, access to health services in transit may be limited or concerns about stigma may cause persons affected to avoid seeking care.
While vaccination against smallpox was shown in the past to be cross-protective against mpox, any immunity from smallpox vaccination will only be present in persons over the age of 42 to 50 years or older, since natural exposure to smallpox and smallpox vaccination programmes ended in 1980 after smallpox eradication. None of the four newly affected countries has access to mpox vaccines or antivirals.
Based on the above, WHO has separately assessed the risk of mpox in the eastern Democratic Republic of the Congo and neighbouring countries as high and in Cote d’Ivoire, and other West African countries as moderate. This risk applies to the general population, especially those who have sexual contact with a mpox case, as well as health workers if they are not taking appropriate precautions when examining, testing and treating mpox cases.
Currently no deaths have been reported in the five above mentioned countries, however, there is the potential for increased health impact with wider spread among vulnerable groups such as children, immunocompromised individuals, including persons with uncontrolled HIV infection or advanced HIV disease, or pregnant women in whom mpox can be more severe.
There is concern that the mpox outbreak in Africa will continue to evolve given:
- The evidence of possible under-detection and under-reporting of local transmission. Many reported cases have no established epidemiological link and have been identified in different countries and in different locations within each country.
- While all of the governments have activated emergency responses in the countries, with support from in-country and global partners, resources to respond remain limited in some of the countries, and resource mobilization may be slow. Technical and financial support is needed to ensure a robust response at national and provincial/local levels.
- Although the governments and partners are all mobilized to support adequate patient care for affected patients and introduce vaccines for people at risk, these measures are currently not in place in most countries in Africa, and their acquisition and roll-out will still require some time for implementation.
- Since some of the countries have not reported mpox before, public awareness of the disease, as well as knowledge about and capacity for identifying it among health and care workers in newly affected countries remains limited.
- Concurrently, the global multi-country outbreak of mpox is still ongoing. Countries outside of Africa that seemed to have achieved control of human-to-human transmission continue to detect sporadic cases ` outbreaks, and an unprecedented increase of cases and reporting countries has been observed in the African Region, especially in the Democratic Republic of the Congo, increasing the risk of further transmission in the region and the whole world.
That said, as our global immunity to smallpox wanes, we become increasingly vulnerable to these types of poxviruses, and what we can say about their abilities today may not hold true tomorrow.
We got lucky in 2022 in that it was the milder clade II mpox virus that escaped from Africa and began to spread globally (see below). Despite > 100,000 cases, the global emergency was ended in less than a year.
While our current knowledge is incomplete, this time we appear to be faced with a far more formidable virus. How seriously we take the threat now may well determine how much impact mpox clade Ib - or its descendants - will have on society in the future.
