Monkeypox first case was reported by the UK Health Security Agency (UKHSA) on 7 May and is believed to be imported. On 14 May 2022, two more cases were identified in the UK, both living in the same household, but with no recent history of travel and no contact with the case reported on 7 May. A further four cases were confirmed by UKHSA on 16 May, also without recent travel history to endemic areas, and were not contacts of the cases reported on 7 and 14 May. All cases reported on 16 May were men self-identifying as men who have sex with men (MSM).
Additionally, on 18 May, Portugal reported five confirmed cases of monkeypox, and more than 20 suspected cases. All cases were young men, and all in the Lisbon and Tagus Valley. Spain has also reported eight suspected cases.
Transmission and symptoms of Monkeypox Virus
Monkeypox is a viral disease. Transmission to humans can occur through contact with an infected animal or human, or with human bodily material containing the virus. Transmission between humans mostly occurs through large respiratory droplets. As droplets cannot travel far, prolonged face-to-face contact is needed. The virus can also enter the body through bodily fluids, lesion material, or indirect contact with lesion material.
Symptoms include fever, headache, muscle aches, backache, swollen lymph nodes, chills and exhaustion. A rash typically develops. This often begins on the face, and then spreads to other parts of the body including the genitals. Of note, the recently detected cases among MSM have reported a preponderance of lesions in the genital area. The rash goes through different stages, and can look like chickenpox or syphilis, before finally forming a scab, which later falls off. The difference in appearance from chickenpox or syphilis is the uniform evolution of the lesions. The incubation period is typically 6 to 16 days but can be up to 21. When the scab falls off a person is no longer infectious.
Since 2018, there have been 7 cases of monkeypox reported in the UK (in 2021, 2019 and 2018), mainly with travel history to endemic countries. However, the this is the first time that chains of transmission are reported in Europe without known epidemiological links to West and Central Africa. These are also the first cases worldwide reported among MSM. The monkeypox virus is considered to have moderate transmissibility among humans.
In this event, transmission between sexual partners, due to intimate contact during sex with infectious skin lesions seems the likely mode of transmission among MSM. Given the unusually high frequency of human-to-human transmission observed in this event, and the probable community transmission without history of traveling to endemic areas, the likelihood of further spread of the virus through close contact, for example during sexual activities, is considered to be high. The likelihood of transmission between individuals without close contact is considered to be low.
The extent of community transmission is currently unknown. However, targeted testing of individuals with such clinical manifestations is beginning in affected EU/EEA countries.
The clinical manifestation of monkeypox is usually mild. The West African clade, which has so far been detected in the cases reported in Europe, has been observed to have a case fatality rate of 3.6% in studies conducted in African countries. Mortality is higher among children and young adults, and immunocompromised individuals are especially at risk of severe disease. Most people recover within weeks.
Healthcare practitioners should consider monkeypox infection as a differential diagnosis for individuals presenting with compatible clinical symptoms and should contact specialised services.
Public health organisations and community-based organisations should take steps to raise awareness on the potential spread of monkeypox in communities of individuals identifying as MSM or having casual sex or who have multiple sexual partners.
Individuals presenting with such symptoms should seek specialist care. Those individuals engaging with multiple sexual partners or having casual sex should be particularly vigilant.
Suspected cases should be isolated and tested and notified promptly. Back-wards and forwards contact tracing should be initiated for positive cases. If smallpox vaccines are available in the country, vaccination of high-risk close contacts should be considered after a risk-benefit assessment. For severe cases, treatment with a registered antiviral can be considered, if available in the country.
ECDC is monitoring the situation closely and is in contact with EU Member States and participant countries of the Health Security Committee. A rapid risk assessment is under development and will be published early next week.
ECDC has previously published a rapid risk assessment “Monkeypox cases in the UK imported by travellers returning from Nigeria – 2018” and a factsheet for health professionals on monkeypox.