In 2022, the Netherlands, among others, was confronted with a major MPox outbreak. It now appears that the virus variant has been circulating among people since 2016, but remained under the radar.
A study by Áine O’Toole et al. that recently appeared in Science shows that the mpox virus (formerly monkeypox) already had more mutations than expected in 2022. Compared to the virus that circulated in Nigeria in 2018, the virus from the 2022 outbreak had as many as 42 mutations, while it was expected to pick up only one mutation every three years as it occasionally jumps from animals to humans. Based on the number of mutations, the researchers estimate that the 2022 MPox virus variant has been circulating dormantly among humans since 2016. They also saw that the mutations have certain characteristics that indicate that the so-called apobec3 played a decisive role. That is an antiviral enzyme of the human immune system. This points to human-to-human transmission rather than spillover from the animal kingdom.
Since the start of the outbreak in 2022, the virus has been diagnosed in 1,278 people in the Netherlands, according to the RIVM. A vaccine is now available. Despite the very low number of infections, according to the researchers, global surveillance is still necessary.