While the World Health Organization (WHO) persisted before the risk of monkeypox warns, there is at least a certain all-clear signal with the available therapy options. According to German scientists, the existing antiviral drugs are also effective in the current outbreak.
Experts from the Goethe University in Frankfurt am Main and the University of Kent (Canterbury) now have proof of this in the “New England Journal of Medicine” released. The background: The monkeypox virus is closely related to the smallpox virus (variola virus), which caused large outbreaks with high death rates of around 30 percent until it was eradicated by vaccination in the late 1970s. Monkeypox infections cause a milder illness. Despite this, the death rate is regarding three percent. People with a weakened immune system, the elderly, pregnant women, newborns and small children are particularly at risk from a severe course.
Until recently, monkeypox was only found in certain parts of Africa when humans contracted it through contact with wild animals, primarily rodents such as the Gambian hamster rat or the red-shanked squirrel. Since May last year, however, a large monkeypox outbreak outside of Africa has been registered practically worldwide and for the first time. The viruses spread exclusively through human-to-human transmission. This is new and may have something to do with mutations in the pathogens. The WHO has classified it as a “public health emergency of international concern”.
Drugs developed once morest “real” smallpox
About 10 percent of monkeypox patients require hospital treatment. In addition, the current monkeypox outbreak differs from previous outbreaks not only in its transmission path, but also in the symptoms of the disease. “These differences in the behavior of the virus gave rise to fears that the monkeypox viruses currently circulating had changed so much that they would no longer respond to the available drugs,” Goethe University said in a press release. The fear: The existing drugs for treating such an infection might no longer be fully effective due to virus mutations.
Jindrich Cinatl from the Institute for Medical Virology (University Hospital Frankfurt) and Martin Michaelis from the School of Biosciences at the University of Kent provided evidence to the contrary. They were able to isolate monkeypox viruses from twelve patients in the current outbreak and multiply them in cell cultures. This allowed these apepoxvirus isolates to be systematically tested in cultures of skin cells naturally infected by apepoxvirus for their susceptibility to three available drugs used to treat monkeypox: tecovirimate, cidofovir and brincidofovir.
Tecovirimat was developed to treat “real” smallpox. This was also regarding a remedy once morest the use of the pathogen as a biological weapon. The substance inhibits a protein that is involved in the formation of the viral envelope as part of the replication cycle. Cidofovir and brincidofovir are so-called polymerase inhibitors. Blocking these enzymes prevents virus replication. This also works with cytomegalovirus infections, for example, and brincidofovir has also been tested experimentally once morest Ebola viruses and herpes pathogens.
Apart from vaccination as prophylaxis once morest monkeypox infection, the treatment options are apparently still good. “The results showed that all 12 patients continued to respond to treatment with clinically achievable concentrations of commonly used drugs,” the German university wrote. According to the publication in the world’s most respected medical journal, when the drugs are taken in the usual doses, an active substance concentration in the blood plasma is achieved that is between 2.5 and 1,000 times the level that should be given in therapy. Cinatl: “We were really worried that the virus might have changed in such a way that it would have become resistant to current therapies. Fortunately, this is not the case.”
