Human monkeypox (MPX) is a zoonotic disease caused by the “MPXV” virus, characterized by a clinical picture resembling smallpox. Endemic to parts of Central and West Africa, monkeypox is not a notifiable disease in the EU. From 2018 to the end of 2021, 12 travel-associated cases of MPXV have been reported outside of Africa. Since 2022, for the first time, many outbreaks have been reported in EU Member States and around the world, and to date nearly 500 cases have been recorded in France.
Monkeypox virus is an enveloped double-stranded DNA virus of the genus orthopoxvirus of the family Poxviridae. Like all “poxviruses”, monkeypox has an extraordinary resistance to drying, a high tolerance to temperature and pH compared to other enveloped viruses.
These characteristics greatly favor its persistence in the environment.
Materials from infected patients (eg, skin crusts) or fomites (eg, bed linen) may remain infectious for months or even years. However, poxviruses are sensitive to disinfectants.
The incubation period for MPX is usually 6-13 days but can range from 5-21 days. Human monkeypox infection often presents with a combination of the following symptoms: fever, headache, chills, exhaustion, asthenia, swollen lymph nodes, back pain, and muscle pain. Typically, within three days of the onset of these symptoms, a rash occurs that begins from the site of primary infection and quickly spreads to other parts of the body. These lesions progress, generally in 12 days, simultaneously from the stage of macules to papules, vesicles, pustules, crusts, before falling. For most affected patients, MPX is a self-limiting disease, lasting 2 to 4 weeks before usually full recovery.
Monkeypox is known to be transmitted by zoonotic transmission and infections have been reported following human-to-human transmission, this study assessed the risk of transmission through contact with contaminated surfaces.
Meticulous sampling in patient rooms
The researchers took different samples from multiple sites in the rooms of 2 contaminated patients, and adjacent rooms in the hospital, in which hospital staff put on and took off their personal protective equipment (PPE). Contamination with up to 105 viral copies/cm2 on surfaces was estimated by PCR and virus was successfully isolated from surfaces with more than 106 copies. In summary, the analysis finds that:
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all surfaces touched by patients have viral contamination;
- the highest loads are detected in the bathrooms;
- cloth surfaces such as towels, gowns, or pillowcases used by patients also show viral contamination.
Viral contamination is not necessarily synonymous with infectious risk: the authors point out that there are currently no precise data on the dose of virus that can lead to monkeypox infection in humans: “despite high contamination with up to 105 cp/cm2 as well as recovery successful virus up to a total of >106 copies, our results do not provide evidence that infection can occur through contact with contaminated surfaces.” Finally, the detection of viral DNA by PCR does not necessarily mean, and generally speaking, that there is a risk of infection.
Nevertheless, rigorous prevention is essential: the prevention of the spread of the virus from symptomatic patients must nevertheless remain rigorous. Researchers emphasize the importance of regular disinfection of frequent hand and skin contact points during care processes, regular cleaning of rooms, and disinfection of surfaces with virucides to reduce the risk of nosocomial transmission.