New Delhi: A recent animal study published in the journal Cell on Wednesday has shown that an experimental Moderna mRNA vaccine for mpox is more effective than existing vaccines in reducing disease symptoms and duration. The study comes amidst an ongoing outbreak of the disease in Africa, which has been declared an international emergency, partly due to the emergence of a new variant in the Democratic Republic of Congo.
According to Jay Hooper, a virologist from the US Army Medical Research Institute for Infectious Diseases and the study’s senior author, researchers aimed to find a “sweet spot” in mpox vaccines that balances high safety and efficacy. Current mpox vaccines, originally developed for smallpox, use a weakened live virus that limits their protective efficacy compared to older, potentially infectious vaccines.
The mRNA vaccine, on the other hand, uses the same technology as Moderna’s highly safe and effective coronavirus vaccine. It includes genetic instructions that train the immune system to recognise four key viral antigens crucial for the virus to attach to cells. In the study, 12 macaques were vaccinated with either the mRNA vaccine or an equivalent of the currently licensed vaccine, while six unvaccinated macaques served as a control group.
Eight weeks after the initial dose, all macaques were exposed to a lethal strain of mpox. Over a four-week monitoring period, researchers assessed the animals’ health and immune responses through blood samples. As expected, all vaccinated animals survived, regardless of the vaccine type, while five out of the six unvaccinated animals died.
“But if we focus specifically on the outcomes with the mRNA vaccine, what we saw was quite surprising and exciting,” co-senior author Galit Alter, a virologist and immunologist at Moderna, told AFP.
What is mpox?
Scientists first discovered mpox, formerly known as monkeypox, in 1958 when they observed outbreaks of a “pox-like” disease among monkeys. Prior to recent events, the majority of human cases occurred in central and West Africa, primarily affecting individuals who had close contact with infected animals.
In 2022, the virus was confirmed to spread via sex for the first time and triggered outbreaks in more than 70 countries across the world that had not previously reported mpox. Mpox is a member of the same viral family as smallpox, but it typically causes less severe symptoms, including fever, chills, and body aches. In more serious cases, individuals may develop lesions on various parts of the body, such as the face, hands, chest, and genitals.
