- New smallpox outbreak in Africa <unk> with global implications?
How concerning the local situation is can be seen from the numbers alone. The African Union's health agency (Africa CDC) has recorded 14,250 cases of Mpox – previously known as "monkeypox" – from the beginning of the year until the end of July, almost exactly the same number as in the whole of the previous year. But even then, there was an increase of almost 80 percent compared to 2022. Since then, infection numbers have been rising exponentially.
Almost all cases currently come from the Democratic Republic of Congo, including 450 of the 456 fatal cases reported in the first seven months of this year. However, first cases are now also appearing outside the Congo's borders, for example in the Central African Republic, Rwanda, and Cameroon and Nigeria. According to the Africa CDC, 16 African countries are now affected by the Mpox outbreak, and a further 18 countries on the continent are threatened.
How Mpox ("monkeypox") is transmitted
Infection occurs through close contact with infected animals or humans. After an incubation period of 5 to 21 days, disease symptoms can appear, usually pox-like skin lesions, either locally or all over the body. Most patients recover within two to four weeks. However, there are also severe cases with high fever and lymph node swelling, and in the worst case, a fatal infection of the organs, especially the spleen and liver.
African experts often cite frequent changing sexual contacts, co-infections such as HIV, malnutrition, and weakened immune system as decisive risk factors. Often, sex workers and their clients, or men who have sex with men, are affected. This latter group was particularly affected in Western countries during the 2022 outbreak.
Because MPXV, the virus's abbreviation, was first discovered in a Danish laboratory in 1958 in monkeys from Singapore, but monkeys in nature are not the main carriers of this virus, the WHO replaced the long-used term "monkeypox" with the neutral and now also common "Mpox" at the end of 2022. The virus probably crossed over to humans via native rodents decades ago. The first cases were discovered in several African countries in the 1970s. Children were often affected, probably because they picked up the pathogen while playing with the droppings of infected rodents. Sex is not a prerequisite for infection, although it is probably the most common transmission route. And every new transmission gives the pathogen the opportunity to change and adapt to new conditions.
The virus's genetic material can be divided into two groups, which are called "clades" in scientific language. These virus families, designated as Clade I and Clade II, are so similar to each other that the genetic sequences of MPXV are more than 99 percent identical among themselves. The similarity to other pox viruses is also over 90 percent.
Even small differences can have significant consequences. This is particularly true when it comes to the course of diseases. Viruses of Clade II are usually less harmful. It was such viruses ("Clade IIb") that led to the major outbreak in West Africa in 2022 and 2023, resulting in nearly 100,000 infections in a total of 116 countries worldwide. Germany was also affected, with about 3,800 cases, most of which occurred between June and September 2022. After that, Mpox was only diagnosed sporadically in our country. However, new cases continued to occur in larger numbers in Africa.
More dangerous viruses are currently circulating
This time, it is the more dangerous viruses of Clade I that are spreading further in Africa. In the Congo basin, a mortality rate of around 3% of cases has been observed for this genetic group. However, mortality rates of up to 11% have been observed in the past. In contrast, only about 0.2 to a maximum of 3.6% of infections with Clade II were fatal. However, viruses change. As early as April, samples from the Kamituga mining region in eastern Democratic Republic of Congo revealed Mpox viruses of a new subvariant from Clade I. This new genetic group is now called "Clade Ib". Not only are the disease courses caused by it generally more severe than those of Clade II, but mutations are also now occurring within Clade I in a region of the genome that particularly promotes human-to-human transmission. The virus is thus adapting further to its new host.
In 2022, a Portuguese research team discovered a six- to twelve-fold higher mutation rate in this genetic region of the Mpox virus than would be expected based on experience with such poxviruses. Mutations occur randomly, like typos, and the virus often does not survive such genetic errors. However, a mutant may also emerge that carries an evolutionary advantage and can, for example, be transmitted more easily from person to person than older viruses of this type. Unfortunately, this seems to be the case with that Clade Ib that is now spreading in Central Africa. Based on the known mutation rate and comparison with earlier samples, it can be assumed that this MPXV subvariant first appeared as early as July 2023 and has since been spreading.
WHO: Could there be a global health emergency?
It is therefore only logical that authorities such as the Africa CDC and the World Health Organization are closely monitoring the development and taking precautions for a swift containment. Above all, the WHO wants to prevent the global spread of the virus variant from Clade Ib and may declare a global health emergency for this purpose. This is the highest warning level available to it under its statutes, the official name being "Public Health Emergency of International Concern" (PHEIC), i.e., a health emergency of international concern. Covid-19 also had this official status.
However, this is not equivalent to a new pandemic, but rather gives the WHO the opportunity to act internationally coordinated to prevent worse. The WHO Director-General and all 194 contracting states are legally obliged to implement the recommended measures of an emergency committee composed of suitable experts. Both the US Centers for Disease Control and Prevention and its European counterpart currently consider the risk of the new Mpox subvariant to be very low in their respective regions. However, it would be fundamentally wrong to lean back and relax as a result. After all, the virus also does not take a break.
Therefore, the WHO recently presented a strategic framework for global containment and control of Monkeypox for the coming years up to 2027. An effective vaccine already exists, although exact numbers for such a supposed niche product are lacking. A newer review article, which evaluated the available studies, found about 60 percent protection against severe symptoms. Serious side effects were not observed. However, it is not clear to what extent the vaccine also reduces the risk of infection itself. "Imvanex" is the only smallpox vaccine approved in the EU, but it was not available during the 2022 outbreak, so a closely related product of the same manufacturer (Bavarian Nordic A/S) had to be relied upon and imported under the name Jynneos from the USA. However, these supplies were also severely limited due to the sudden global demand.
Such shortages should not recur. Additionally, there is a lack of additional studies on the likely waning effect of vaccines. The WHO's preparedness plan calls for the development of better vaccines and, if possible, antiviral drugs. At least, a PCR test has just been presented that can already detect the new viruses of the Ib clade from their genetic relatives and track their further spread.
Yes, it all costs. But Monkeypox is a good example of why pandemic preparedness as a whole is an indispensable investment in the future - and why it can be very dangerous to postpone such investments. If it's not the Monkeypox virus that surprises us tomorrow, it might be bird flu or some virus that no one knows about yet. The renowned US virologist Anthony Fauci, known worldwide for his HIV research and the COVID-19 pandemic, summed it up in a warning contribution to the "New England Journal of Medicine" two years ago: "It's only over when it's over ... but it's never really over."
The World Health Organization (WHO) is closely monitoring the spread of the more dangerous viruses of Clade I in Africa due to their increased severity and potential for human-to-human transmission. Authorities like the Africa CDC and WHO are taking precautions to prevent a global health emergency, as a declaration of a Public Health Emergency of International Concern (PHEIC) could allow for international coordination to prevent a wider spread. The CDC, along with its European counterpart, currently considers the risk of the new Mpox subvariant to be low in their respective regions.
