Monkeypox: WHO alert, effective treatments, evolution of the virus… Hérault experts analyze the new variant of Mpox

Éric Delaporte and Jacques Reynes, both professors of infectious diseases, discuss the rise in Mpox cases in Africa. WHO alert, virus lethality, effective treatments and the evolution of the epidemic… The two experts shed light on the new variant of monkeypox.

Can you explain what monkeypox is and how it is transmitted ?

Éric Delaporte:It’s a virus from the smallpox family that has nothing to do with monkeys. It was called that because it was initially discovered in monkeys. In Central Africa, Mpox originates from rodents. Until now, these have been very localized outbreaks with very few secondary cases. However, it mainly affected children. Adults were less affected because they had a certain immune memory which meant that vaccination against smallpox protected against Mpox. But now, populations no longer have antibodies against smallpox. What we see today in Africa is the change in the scale of this epidemic. We have gone from a zoonotic epidemic with sporadic cases linked to contact with a rodent to a sexually transmitted infection where the spread can be much more rapid and dangerous.

Jacques Reynes:There was a global epidemic in 2022 that affected France and was limited thanks to the vaccine. What is new now is the identification of a new strain of this virus that was discovered in September 2023 and which has the particularity of being easily transmissible and causing more deaths than before. This variant first affected mine workers and sex workers in the Democratic Republic of Congo and then neighboring countries. Children are particularly affected, which worries schools and families. The mortality rate in children is 10% while in adults it is only 3%. There is a risk of spread through air transport, which explains the imported cases in Sweden and Pakistan.

Why did the WHO trigger a global alert when only one case was imported into Europe ?

Éric Delaporte: The number of cases is becoming increasingly significant in Central Africa. Now, the entire population could potentially be affected. The WHO alert is therefore deliberately early because the best policy is prevention. A significant international effort is needed now to prevent this from becoming a catastrophe by giving the virus time to adapt.

Jacques Reynes:The countries affected are initially countries with a fragile medical system and where vaccines are not widely available. The problem was probably underestimated. This alert was triggered because it is necessary to take mitigation measures and warn the world population. However, in France, the risk is very limited; if an epidemic were to start, we would realize it fairly quickly. Then a good part of the elderly population received a vaccination that protects them at least partially.

A word on the lethality of this infection ? Who can die from it ?

Jacques Reynes :We must understand the context of the Democratic Republic of Congo where the system is not as developed and therefore very fragile. People can die, not just from the virus itself but also from other infectious complications when there are very significant skin lesions. Even if we should not have this mortality rate in Western countries, this strain is still more virulent and aggressive than the previous one.

Are there effective treatments available?

Éric Delaporte: There are several. Certain drug prototypes have a very important action because we will be able to treat contacts very early and avoid serious forms. But in the event of an outbreak, the drug is not produced in sufficient quantities, particularly in Africa.

Jacques Reynes : First there is a latest generation anti-smallpox vaccine, which contains few & rsquo;adverse effects and which should be effective. And there is also an anti-viral treatment that is only used in serious situations in immunocompromised people.

How do you see the evolution of the virus in the coming weeks ?

Éric Delaporte : In the West, the risk is close to zero at the moment. There is a lot of room before a public health risk emerges in Europe. This mainly concerns travelers. On the other hand, in Africa, surveillance is more heightened because the virus is developing in urban areas, which was not the case before. There is obviously a risk of global spread, but this will mainly affect megacities in which health systems are not strong enough.

At the end of the Covid pandemic, many specialists predicted a new epidemic to come in the coming years, could Mpox become part of it ?

Éric Delaporte : No, the modes of transmission are different. The epidemic that is underway in Central Africa does not have any similarities with that of Covid. One is primarily through sexual contact while the other is through the air, which is the worst mode of transmission.

Jacques Reynes: What is frightening about Mpox is that the virus can affect anyone, including children. But we must not become hypochondriacal. The risk is low. The population and health professionals are aware of this problem. We are more aware of the risks of transmissibility and we now have rapid and effective diagnostic methods with molecular biology techniques, so all this changes the situation. We are not at all in the same situation as that of Covid.

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