Is monkeypox mainly transmitted through sexual intercourse?

Smith Collection/Gado/Getty Images While several studies have been published, knowledge of the monkeypox epidemic is beginning to mature. And the idea of ​​transmission during sexual intercourse becomes clearer (microscopic photo taken from a clinical sample and digitally colored).

Smith Collection/Gado/Getty Images

While several studies have been published, knowledge of the monkeypox epidemic is beginning to mature. And the idea of ​​transmission during sexual intercourse becomes clearer (microscopic photo taken from a clinical sample and digitally colored).

HEALTH – This is a question that inevitably has an impact on the way world governments approach the monkeypox epidemic: how is the disease transmitted? More than three months after the appearance of the first cases in Spain, 28,000 patients have been counted worldwide, the first deaths have been reported and large-scale scientific studies are beginning to report their conclusions.

In recent days, three reference scientific publications, the Lancetthe British Medical Journal and the New England Journal of Medicine have thus published initial analyzes which make it possible to learn more about the profile of the infected people, the symptoms from which they suffer and the way in which they were able to contract the disease.

The bodily relationship, dominant transmission mechanism ?

All of these studies outline the same typical portrait of the patient: an adult man maintaining homosexual relations. A novelty compared to this disease already well known in Africa, but which mainly affects children there. Thus, the study of The Lancetcarried out in medical structures in Madrid and Barcelona, ​​speaks of 92% of the 181 patients as being men who have sex with men compared to 8% of women (3%) and heterosexual men (5%).

Proportions that are found in the feedback from Public Health France. In its report of August 4, the National Agency evoked an immense majority of men having sex with men among the patients (96% of the cases for which the sexual orientation is informed).

The other notable element of the study of the British journal concerns the mode of transmission. Because if, since the start of the epidemic, scientists have feared to deliver hasty conclusions and to stigmatize homosexual men, researchers from the Lancet speak of a significant role of sexual relations in the transmission of the disease. This is in line with the recommendations of the World Health Organization, which has officially invited gay men to reduce their number of sexual partners.

Our study accredits the idea that skin-to-skin contact during sexual intercourse is the dominant mechanism of transmission of monkeypox, with significant consequences on the way in which the disease must be apprehended at the health level. “, can we read in particular in the study. Clearly, the idea that it is a sexually transmitted infection (STI) is not mentioned at this stage; it is above all a question of reducing prolonged skin contact, from mucosa to mucosa, which is particularly likely during sexual intercourse.

What about semen and aerosols?

This observation is found in the areas of the body affected by the physical symptoms: if all the patients in the survey presented skin lesions, 78% were affected in the anogenital area and 43% in the mouth. Same thing at Public Health France which mentions 75% of patients with a ” genito-anal rash “, in addition to bouts of fever and muscle pain caused by the disease. The studies also cite rare complications, but never observed before: inflammation of the rectum or edema of the penis.

Consequently, the question of the relevance of the measures taken to protect populations (particularly isolation) arises. And the authors of Lancet say it clearly: The remarkable difference in viral load between lesion readings and throat readings deserves further study to best guide the decision whether or not to isolate people. “At present, in France, the sick are forced to isolate themselves for 21 days as an example.

Thus, the trail of airborne transmission loses credibility. In an interview with the magazine Sciencethe author of the study summarizes the conclusions of his team as follows: The viral load is very high in skin lesions and very low in the respiratory tract, which explains why it is likely that sexual transmission continues “.

However, many areas of darkness remain, which only in-depth studies on a larger sample of patients will shed light on. Starting with a hypothesis which, if not excluded, is for the time being anything but accredited by research, namely that of transmission by sperm.

A doubt about the effectiveness of the old vaccination

Another uncertainty relates to the effectiveness of an old vaccination. Indeed, in the study of Lancet18% of patients were vaccinated in childhood against smallpox, a virus similar to that of monkeypox and whose vaccines are supposed to be effective). Which makes the authors say that “ further investigations are needed to fully understand the protection offered by vaccination (Ancient, editor’s note) in the context of the ongoing epidemic “. This while noting however that this vaccination against smallpox, generalized by the WHO in the late 1960s until the eradication of the disease, can go back decades, which could explain a drop in effectiveness.

Still on vaccination, researchers published by The Lancet warn: Due to a short incubation period (seven days on average, editor’s note) vaccination of risk groups before exposure to the disease is probably more effective than post-vaccination if health authorities want to control the epidemic. »

Last point raised by the data from the various studies: the link between being infected with monkeypox from another disease. Indeed, without knowing if it is a simple correlation or if a direct link exists, the study of The Lancet notes that 40% of patients are also infected with HIV. In France, in the figures from Public Health France, they are 26% in the same case, and 5% of patients are immunocompromised.

See also on the HuffPost: Faced with monkeypox, why is the gay community concerned?

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