The monkeypox virus is often transmitted before the first symptoms appear, suggests a study published on Wednesday, the results of which are yet to be confirmed but which could play an important role in managing the epidemic.
The “presymptomatic transmission” of monkeypox, whose symptoms are mainly characterized by skin rashes, seems “considerable”, according to the authors of this study published in the British Medical Journal (BMJ).
This work was carried out in the United Kingdom, one of the first countries where the current epidemic spread. This caused, from spring, the appearance of many cases of monkeypox in Europe and the American continent, while until now the disease was mainly present in several African countries.
The risk of “silent” transmission
If the epidemic, which has affected nearly 80,000 patients and caused around thirty deaths, seems to subside at the moment, the health authorities remain vigilant.
Therefore, it is important to know the risk of “silent” transmission, that is, during the incubation period before the patient presents the first symptoms.
The study authors, led by epidemiologist Thomas Ward, attempted to answer this question by examining data from nearly 3,000 British patients. As with the current epidemic as a whole, it is mostly men who have had same-sex relationships.
More than half of the cases
This examination allowed to have an idea of two types of delays and to compare them with each other. The first is the incubation time, during which the patient unknowingly carries the virus. The second is the time that elapses from the onset of symptoms in a given patient, until their appearance in the one to whom the disease was transmitted.
The researchers concluded that this second delay tends to be shorter than the first, suggesting transmission before the first symptoms. They estimate that this presymptomatic transmission accounts for more than half of cases, and can occur up to four days before symptoms appear.
However, these results still need to be confirmed by other studies, other researchers say in a comment also published by the BMJ. At present and even with this work, presymptomatic transmission “is not irrefutable”, they warn.
However, they believe that the study marks an important step in this direction, due to the large sample of patients and the seriousness of the statistical models used.
Source: BFM TV
