2022 monkeypox outbreak in France

Monkeypox is an infectious viral disease that can occur in humans and some other animals.[2] Symptoms include fever, swollen lymph nodes, and a rash that forms blisters and then crusts over.[2] The time from exposure to onset of symptoms ranges from five to twenty-one days.[3][4] The duration of symptoms is typically two to four weeks.[4] There may be mild symptoms, and it may occur without any symptoms being known.[3][5] The classic presentation of fever and muscle pains, followed by swollen glands, with lesions all at the same stage, has not been found to be common to all outbreaks.[2][6] Cases may be severe, especially in children, pregnant women or people with suppressed immune systems.[7]

The disease is caused by the monkeypox virus, a zoonotic virus in the genus Orthopoxvirus.[8] The variola virus, the causative agent of smallpox, is also in this genus.[9] Of the two types in humans, clade II (formerly West African clade)[10] causes a less severe disease than the Central African (Congo basin) type.[11] It may spread from infected animals by handling infected meat or via bites or scratches.[12] Human-to-human transmission can occur through exposure to infected body fluids or contaminated objects, by small droplets, and possibly through the airborne route.[2][12] People can spread the virus from the onset of symptoms until all the lesions have scabbed and fallen off; with some evidence of spread for more than a week after lesions have crusted.[11] Diagnosis can be confirmed by testing a lesion for the virus's DNA.[13]

There is no known cure.[14] A study in 1988 found that the smallpox vaccine was around 85% protective in preventing infection in close contacts and in lessening the severity of the disease.[15] A newer smallpox and monkeypox vaccine based on modified vaccinia Ankara has been approved, but with limited availability.[3] Other measures include regular hand washing and avoiding sick people and animals.[16] Antiviral drugs, cidofovir and tecovirimat, vaccinia immune globulin and the smallpox vaccine may be used during outbreaks.[17][18] The illness is usually mild and most of those infected will recover within a few weeks without treatment.[18] Estimates of the risk of death vary from 1% to 10%, although few deaths as a consequence of monkeypox have been recorded since 2017.[19]

An ongoing outbreak of monkeypox was confirmed on 6 May 2022, beginning with a British resident who, after travelling to Nigeria (where the disease is endemic), presented symptoms consistent with monkeypox on 29 April 2022. The resident returned to the United Kingdom on 4 May, creating the country's index case of the outbreak.[20] The origin of several of the cases of monkeypox in the United Kingdom is unknown. Some monitors saw community transmission taking place in the London area as of mid-May,[21] but it has been suggested that cases were already spreading in Europe in the previous months.[22]