Experts do not fear that the monkeypox virus will cause a new pandemic. Nevertheless, the increased incidence of infections outside of Africa has attracted increased scientific attention.
Charlotte Hammer, an epidemiologist at Downing College in Cambridge, believes that the current development is unusual because there have not been any major outbreaks of monkeypox in Europe so far. She expects more cases, she told the Science Media Center (SMC). However, since the transmission apparently takes place via close physical contact – via body fluids, skin rash and smear infections – a large outbreak is rather unlikely.
The Munich virologist Gerd Sutter also assesses the risk of a major epidemic in Germany or Europe as low. He also thinks the possibility of the virus entering animal reservoirs in Europe is unlikely, as he told the SMC. The virus is usually transmitted from person to person in very close contact with infected people.
Although transmission through aerosols, such as with Covid-19, has been experimentally proven, it plays at most a subordinate role in natural infection, according to Sutter. “Transmissions of monkeypox are therefore relatively inefficient compared to other infections such as influenza or Covid-19 and, in conjunction with adequate measures for diagnosis and contact determination, usually only lead to the formation of short chains of infection.”
The cases of monkeypox currently observed in Europe are most likely infections originally imported from Nigeria, which are now presumably being transmitted from person to person in limited chains of infection. According to Sutter, initial genetic studies in Great Britain had identified a virus strain that can be assigned to the monkeypox viruses occurring in West Africa.
According to researchers, this West African strain causes milder diseases and has a lower mortality rate than other strains of the virus. In general, the mortality rate for West African monkeypox is one percent, which primarily affects children under the age of 16. According to health authorities, the virus usually causes mild symptoms such as a rash, fever and pustules, but can also have severe, sometimes fatal outcomes.
Doctors assume that the older generation that was vaccinated against classic smallpox before 1980 also has a very high level of protection against monkeypox. “These people are at very little or no risk at all,” says Clemens Wendtner, chief physician of the infectious disease clinic at the Schwabing Hospital in Munich. Vaccination with the new smallpox vaccine Vaccinia Ankara, which is approved in Europe, Canada and the USA, is also possible, as virologist Sutter said. With the drug Tecovirimat, there is also a therapy option approved in the EU.
Fabian Leendertz, epidemiologist at the Robert Koch Institute, is already assuming an epidemic. “However, it is very unlikely that this epidemic will last long,” he told the SMC. The cases can be narrowed down well via contact tracing, medicines and vaccines are available.
A key question now is why the virus is suddenly causing more outbreaks outside of Africa. Epidemiologist Charlotte Hammer pointed out that there are large knowledge gaps: “We currently know very little about monkeypox because research on this is underfunded and underrepresented.”
Fabian Leendertz therefore relies on good epidemiological data to understand whether and how the cases are related. The sequencing of the monkeypox virus genome would also be important. “Because that way we could see whether there are indications of a change in the pathogen, which, for example, suggest better transmissibility,” said the epidemiologist.
The World Health Organization (WHO) calls for a number of measures to prevent the further spread of monkeypox. It was “urgently necessary” to raise awareness of the virus, said the UN organization in Geneva on Saturday night. In addition, cases would have to be identified and isolated comprehensively, and routes of infection would have to be traced. According to the WHO, the diseases that have so far become known in Europe, North America and Australia mainly – but not exclusively – affected men who have same-sex sex.
It is very likely that cases will appear in other populations and countries. As of Saturday, the WHO assumed around 90 confirmed infections and 30 suspected cases outside of Africa. After a first case in Bavaria, there were also two confirmed cases of monkeypox in Berlin at the weekend.