Health

This mysterious virus protects against monkeypox

Monkey pox in Italy and Europe

It is a virus that has now disappeared and is only contained in smallpox vaccines.

monkeypox virus/NIAID

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Monkey pox in Italy and Europe

The vaccines used to eradicate human smallpox, and those used today against monkeypox, are based on an unknown virus, which no one has ever been able to identify: a pathogen that could be described as “ghost”, so far only present in vaccine form. . Despite nearly three-quarters of a century of research, no one knows how, why, or specifically when this virus was first used as a smallpox vaccine, or if it still exists in nature. The only thing certain is that millions of people who lived in the era of human smallpox owe their lives to its existence: without this enigmatic virus, it is also likely that the current monkeypox epidemic would have spread even faster. .

Smallpox is the virus that protects against disease

To take stock of the issue, it is the virologist José Esparza of the Robert Koch Institute, in Germany. ” For many years – he says to BBCpeople assumed that what we call cowpox was the same virus as cowpox. But it turned out that these two viruses were different, and we have since accepted that the cowpox virus is a specific pathogen, and that the cowpox virus is another virus of unknown origin.“. In other words, thanks to modern investigative techniques, researchers have realized that the vaccine is a member of the Orthopoxvirus group, a genome of viruses with a double-stranded DNA genome, which includes both human smallpox and several other mammalian viruses, including camelpox, cowpox, cowpox, rabbit, rat pox, monkey pox, and raccoon pox, but none of the above.

Vaccinatedin particular, it was found to be linked to a horsepox virus, identified in Mongolia in 1979.” It’s very similarexplains Esparza who, with his collaborators, has sequenced many other historical vaccines. ” In 31 samples, we did not find cowpox in any of them“. Therefore, it appears that most smallpox vaccines of the 19th and early 20th century were produced from horsepox, not cowpox, which was probably never used, or may -be was quickly replaced by its equine cousin, as suggested by the research team at the Robert Koch Institute. , who also recently found unpublished evidence of a sea change in the vaccines used to prevent human smallpox, which happened around 1930, and the researchers they are currently studying.

Basically, compared to the vaccine introduced by the British Edward Jenner in 1796, which was based on the transfer of a smallpox virus from one person to another, in 1860 Italian and French scientists introduced the animal vaccine. ” Instead of transmitting the virus from human to human, they found they could put it back into the cows and keep it in the cows – Esparza clarifies -. Eventually, this mass production system spread to other animals, including sheep, horses, and donkeys.”.

At some point, a virus from an unknown animal began to be used as a smallpox vaccine. ” There’s no record of who did it, or when, why or how he did it, but it’s possible it was just an accident – someone may have salvaged what he thought it was horse or cowpox on a farm, when in fact it was another unidentified virus. Which worked fine, so no one noticed“.

Some time after 1930, this mysterious virus became the most common vaccine, and by the mid-20th century hundreds of different versions were circulating around the world. Then, in 1966, the World Health Organization announced the campaign to eradicate smallpox and chose only six vaccine strains that would be used to achieve it. As the decade progressed, the dominance of the unknown virus became more entrenched.

But where is this virus now? And why has no one ever found the natural host for the vaccine? Researchers believe this strain once caused regular outbreaks in parts of Europe, but wasn’t identified in the wild until 1976, when horses began falling ill with injuries and febrile symptoms in Mongolia. Improved agricultural practices and better diagnosis are thought to have led to extinction. ” Smallpox virtually disappeared from Europe in the early 20th centuryEsparza pointed out, believing that the mysterious virus used in modern human smallpox vaccines may have met the same fate. ” We hypothesized this possibility“.

The virus in the monkeypox vaccine

Today, this virus is more useful than ever against monkeypox, a close relative of human smallpox but which tends to primarily infect rodents and non-human primates and is transmitted primarily through contact with body fluids or contaminated objects. . Unlike human smallpox, monkeypox was first discovered in 1970, and until recently infections were mostly confined to Africa.

But from May 2022, it began to spread around the world, with unprecedented spread in humans. To slow it down, many countries have ordered millions of doses of two previously used smallpox vaccines – the Imvanex vaccine developed by Bavarian Nordic and the ACAM2000 vaccine manufactured by Sanofi Pasteru Biologics Co and Emergent BioSolutions – two serums that are exceptionally safe and considered highly effective. , both from the same enigmatic virus that became the dominant smallpox vaccine in the 1930s. the vaccine it is always in high demand.

But will we ever know where this virus comes from? Esparza is skeptical. “We still have more questions than answers.Concludes the expert, while revealing that he and his colleagues have made some progress in the research and that in the coming months they will reveal interesting details.

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