This is the fear that has been growing for several weeks: could Mpox eventually cause a global pandemic such as the one we experienced with Covid-19? A concern that the WHO is trying to temper. “Mpox is not the new Covid. Whether it is clade 1 of Mpox, at the origin of the current epidemic in central and eastern Africa, or clade 2 of Mpox, at the origin of the 2022 epidemic” worldwide, assured the European director of the World Health Organization, Hans Kluge, on Tuesday, August 20.
“We already know a lot about clade 2. We still need to learn more about clade 1,” he said, noting that “we know how to fight Mpox.”
An international public health emergency in Africa
The resurgence of Mpox in the Democratic Republic of Congo (DRC), carried by clade 1b which also affects Burundi, Kenya, Rwanda and Uganda, prompted the WHO to declare a public health emergency of international concern on August 14, the highest level of health alert. The WHO had already taken such a decision in 2022 when an Mpox epidemic, then carried by clade 2b, had spread across the world. The alert was lifted in May 2023.
Hans Kluge also wanted to point out that two years ago, Europe had “brought Mpox under control thanks to direct engagement with the most affected communities, men who have sex with men”. In France, 232 vaccination sites are already open to deal with this epidemic, resigning Prime Minister Gabriel Attal also indicated on Tuesday, while promising 100,000 doses of vaccines to the most affected countries.
A new variant
Formerly known as monkeypox, the virus was discovered in 1958 in Denmark, in monkeys bred for research. Then in 1970 for the first time in humans in what is now the DRC (formerly Zaire), previously known as the Congo Basin clade then as clade 1, and now clade 1a after the recent discovery of the 1b variant in the DRC.
“Clade 1a is what used to be called the Congo Basin clade,” and people are usually infected by infected animals, said Dr. Catherine Smallwood, head of emergencies at the WHO’s European office. “We have not isolated or detected zoonotic transmission of clade 1b,” she said. “So this appears to be a strain of the virus that is circulating exclusively in the human population, and some of the viral changes that virologists have identified tell us that it is likely to be more effective in transmitting between humans.”
“We know that clade 1 is more dangerous than clade 2,” said Tarik Jasarevic, a WHO spokesman in Geneva, but experts are now investigating whether there is a real difference between clade 1a and clade 1b, in terms of severity. “It is only recently that we have discovered clade 1b, which is spreading rapidly […] but we are not yet sure of its seriousness,” he added.
No confinement, no masks
According to Hans Kluge, the risk to the general population is “low”, even if the modes of transition of the virus “are not yet very clear”. “Are we going to have to confine ourselves as was the case in Europe in the face of Covid-19? The answer is clearly no”, he also said.
WHO spokesman Tarik Jasarevic said the organization does not recommend wearing masks. And, he said, “we do not recommend mass vaccination. We recommend using vaccines in the event of an outbreak for the most at-risk groups.”
According to the WHO, two vaccines have already been used in recent years: MVA-BN, from the Danish pharmaceutical company Bavarian Nordic, and LC16, produced for the Japanese government. There is a third vaccine, said Tarik Jasarevic, ACAM2000, which the Strategic Advisory Group of Experts on Immunization (SAGE), a WHO committee, recommends “in case MVA-BN and LC16 are not available.”