The monkeypox epidemic is progressing. More than 26,000 cases were counted on Thursday in 80 countries, since January 31, 2022. The United States and Europe – primarily Spain, the United Kingdom, Germany and France – are one of the most affected countries with nearly 90% of the cases recorded. In Switzerland, 304 cases of this disease have been confirmed, with an exponential progression for several weeks. “The number of cases is currently doubling every fortnight in the world, observes Antoine Flahault, director of the Institute of Global Health at the University of Geneva. At this rate, we should approach 80,000 cases outside Africa by the end of the month. This is a very worrying development.” The Director General of the WHO recently declared this epidemic a public health emergency of international concern and the UN organization has activated its highest level of alert. Back on the evolution of the situation in several points.
■ Who is contaminated?
The virus is currently circulating in a population group mainly made up of men aged between 18 and 44, according to a WHO report dated August 3, and 97.5% of cases with known sexual orientation are identified as men who have sex with men. A very small portion of cases fall outside this category.
The incubation period after infection lasts between 5 and 21 days. The first symptoms are typically fever, fatigue, headache and muscle aches, followed by the appearance of skin lesions on the genitals but also potentially on the whole body, and even inside the stuffy. Contamination occurs through contact with one of these lesions followed by self-inoculation. Faced with the surge in cases, the WHO last week for the first time recommended that the men affected reduce the number of their sexual partners.
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If homosexuals are the main victims of the epidemic, for the moment, nothing indicates that they should remain so. “The mode of transmission does not seem – or not exclusively – to be sexual, but more by contact between diseased skin and healthy skin, a bit like scabies, observes the Geneva epidemiologist. One of the next groups that could be affected could well be children between whom it is difficult to limit the often close contacts, especially at school. In its report, the WHO mentioned 96 cases of children under 17 suffering from monkeypox.
“The increase in cases means that one day transmission will most certainly overflow into other populations outside the current population group, comments Laurent Kaiser, director of the Center for Emerging Viral Diseases at HUG. It would require a change in the behavior feeding the chain of transmission, such as avoiding intimate or sexual relations with strangers or without a condom. However, changing behavior remains difficult and partly illusory. There remains another solution: vaccination.
■ Can I get vaccinated?
Currently, there is no specific vaccine against monkeypox. The latter is part of the large family of orthopoxviruses to which also belongs that of smallpox, a disease eradicated from the planet in 1980 following vaccination campaigns. The only vaccine used by several countries to block the spread of this virus was developed based on a vaccinia virus, another orthopoxvirus, originally to protect against smallpox, as part of the fight against bioterrorism. On his websitethe WHO says, “Observational studies have shown that smallpox vaccination is 85% effective against its cousin monkeypox.”
This vaccine called Imvanex (or Jynneos in the United States) is made by the Danish company Bavarian Nordic and considered the safest, although there are very few data on its effectiveness. It has been tested on a limited number of laboratory animals and healthy volunteers to assess its safety. These vaccinated individuals developed antibodies against smallpox. Imvanex has never been tested in individuals with or at risk of being infected with monkeypox virus. “We are not certain that this vaccine protects against all infections, perhaps 80%, or even less, adds Laurent Kaiser. I agree to promote the vaccine. It has to be done, but with focus and realizing that there are still a lot of question marks about efficacy and safety. Here we skip a step by authorizing it without study in the population.
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The Bavarian Nordic product has been authorized since June 16 in the United States where it is recommended in risk groups and for the most exposed caregivers. The European Medicines Agency followed suit with the Americans on July 25 by allowing its use. For the time being, the pharmaceutical company has not submitted an application for authorization to the Institute for Therapeutic Products Swissmedic, which indicated on Thursday: “The question of whether the monkeypox vaccine will be subject to a rolling review procedure will depend on the epidemiological situation.”
For its part, the Federal Office of Public Health (OFSP) says it is examining the possibility of centralizing the purchase of a vaccine against monkey pox. At the same time, the Federal Commission for Vaccinations (CFV) is developing recommendations regarding this new epidemic. “The problem in Switzerland is above all access to doses,” says Laurent Kaiser. Switzerland is a small island in the middle of Europe, it weighs less than other buyers; the laws of the market have changed since Covid-19, it is not enough to be rich.”
■ Is monkeypox a serious disease?
In the majority of cases, the disease causes lesions that heal on their own after a few weeks without treatment, often leaving scars. Some patients may also have more severe forms. “The virus can spread throughout the body, with lesions all over the body, or even lead to haemorrhagic forms affecting the organs. Bacterial superinfections can occur when the immune system is too disturbed.
Infection with this virus has been fatal, outside its endemic zone in Africa, in rare cases recently reported in India, Spain, Nigeria, Ghana and South America. “This is a new disease, I expect that we will see deaths and complications, adds the HUG infectious disease specialist. It is too early to have an idea of the lethality of this virus. The population currently affected is young and fairly healthy. It is an aberration and scientific nonsense to say that this disease is not serious because we still know little about it, as well as certain risk factors. Several people could be at risk such as those suffering from comorbidities, the immunocompromised, pregnant women and newborns. “The elderly are not necessarily more at risk because vaccination against smallpox was current in Switzerland until 1972, and it could offer a form of protection”, adds the expert.
Years of smallpox research have led to the development of an antiviral drug, Tecovirimat, which may be useful for patients with monkeypox. This drug, which has not been authorized in Switzerland, was already approved in January 2022 by the European Medicines Agency for use in post-exposure prophylaxis or to prevent complications. Again, data on its effectiveness in the context of a monkeypox outbreak are limited. Clinical trials have been launched to refine the recommendations.
■ Is there a risk of a pandemic?
Yes, and it is taking shape before our eyes, according to the experts interviewed. “Many of us are very worried about the sudden emergence of this virus which had remained contained for fifty years in the intertropical zone of Central and West Africa, comments Antoine Flahault. We are witnessing the development of a new pandemic which has already affected, in less than three months, half of the countries of the globe, and which is spreading at an uncontrolled rate today.
Orthopoxviruses have already proven in the past that they can be formidable. “Nobody therefore has to gain today by letting this virus spread in the population, continues the epidemiologist. Switzerland could still stop its progress, but it is falling behind inexplicably on this spreading disease and it risks regretting it later.
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One of the risks is linked to the evolution of the virus, which is one of the biggest in existence. Its DNA contains more than a hundred genes – while the genome of the flu virus, by comparison, contains ten. If it mutates less than that of Covid-19, its genome could still change. “I think this virus is not taken seriously enough. As long as it is transmitted, it will continue to adapt to humans. It may take time – one, ten, even a hundred years – but to exist it will evolve and mutate like any new virus in humans. We cannot exclude that one day there will be a more widespread transmission, a new form of pandemic. It may be a poisoned gift that we leave to our children.