A new mpox jab using the same technology as Covid vaccines, and currently being tested on Brits, slashes symptoms and cuts transmission of the deadly virus, research shows.
Created by pharma giant Moderna, the new vaccine, dubbed ‘mRNA-1769’, was tested against a deadly strain of mpox directly in a trial involving macaques a, type of primate.
It was also put head-to-head against a vaccine currently used to protect people against the virus which is designed to work on smallpox, which is closely related to mpox.
Experts found the mRNA jab cut the number of mpox lesions, a classic symptom of the disease, in the monkeys by 96 per cent and also reduced the days of illness by 10.
Swabs analysing the blood and saliva of the macaques also indicated lower viral loads among the animals given the mRNA jab.
Created by pharma giant Moderna the new vaccine, dubbed ‘mRNA-1769’, was tested against a deadly strain of mpox directly in a trial involving macaques a, type of primate
This, the authors suggested, might mean it is more effective at reducing the odds of the monkeys passing mpox on to other animals.
The results come a week after experts warned currently available vaccines might not work against a new strain of mpox ripping through central Africa and which has now reached Europe and Asia.
This new strain called clade 1b is far deadlier than the clade 2 strain which spread globally in 2022 and primarily hit gay and bisexual men.
While the Moderna study didn’t test their jab against clade 1b they did test it against clade 1a, which is a close relative and also deadlier than clade 2.
In the study, the results of which are published in the journal Cell, scientists tested three different groups of six macaques.
One group was given the new Moderna jab, the other the classic anti-smallpox mpox jab, and the final group was left unvaccinated as a control.
Vaccinated monkeys were given four weeks after their dose before being exposed to the lethal mpox strain.
Experts then monitored the animals for four weeks taking regular blood tests to examine their immune response.
At the end of trial all 12 vaccinated monkeys survived whereas five out of the six unjabbed macaques died.
Though both jabs reduced the severity of an mpox infection scientists found the mRNA jab appeared to be far more effective.
For example, unvaccinated monkeys with mpox developed a maximum of 1,448 lesions, whereas as those with the standard jab only developed 607, a drop of almost 60 per cent.
But animals who got the mRNA jab only developed a maximum of 54 lesions, a 96 per cent difference.
Monkeys with the mRNA jab were also sick for less time with lesions clearing up 10 days faster than those with the older jab.
This pattern was also replicated in other measures of disease severity with monkeys on the mRNA jab losing less weight during their illness than those on the traditional vaccine.
The Moderna team also said results from the blood and throat swabs showed lower levels of virus in the bodies of the monkeys that got the mRNA jab.
This, they suggested could ‘be more effective at reducing transmission’.
Moderna virology researcher and co-author of the study, Alec Freyn, said the experiment was the first to test an in-development mpox jab against current vaccination options.
‘When we put those vaccines head-to-head in primates, we saw improved responses from the mRNA vaccine in terms of not just protection from survival but also fewer lesions, shorter duration of disease, and less viral shedding in the blood and respiratory tract,’ he said.
Fellow author Galit Alter, a virologist and immunologist at Moderna, said the mRNA technology behind the jab, the same used to make the company’s Covid jabs, was responsible for the enhanced protection.
‘With the mRNA vaccine, we’re able to pick pieces of the virus that can give the most potent and most effective immune response,’ she said.
‘By doing that instead of being distracted by an entire virus, you’re able to narrow down on the pieces of the virus that give you protection.’
In the case of mRNA-1769, the jab targets four parts of the virus which are critical for it to attach and enter human cells.
An additional part of the study was testing antibodies generated by the monkeys’ immune systems that are designed to fight off pathogens like mpox and other viruses.
Mr Freyn said these results were positive.
‘It neutralized not only mpox but also vaccinia, cowpox, rabbitpox, camelpox, and ectromelia virus. We believe that this vaccine may protect from other threats that may emerge in the future.’
mRNA-1769 is currently being tested among 350 Brits in England aged between 18 and 49.
This trial is designed to measure various doses of the jab’s safety and immune response in humans.
Unlike the newly published research, it doesn’t involve exposing people to potentially lethal mpox. It is due to conclude in June next year.
While the Moderna authors referenced the current outbreak in their study, they didn’t speculate on the potential effectiveness of their new jab in this context.
The new strain of mpox, formerly called monkeypox, is far deadlier than the mild strain which spread to over a dozen countries, including the UK in 2022.
It kills about one in 20 adults it infects but the mortality rate rises to one in 10 in children.
In comparison, clade 2 and only killed roughly about one in every 500 people that caught it.
The virus spreads primarily through skin-to-skin contact which can include sex or through direct care, for example mother to child.
Clade 1b has swept through central Africa killing hundreds since the outbreak began.
A woman cares her baby suffering from a severe form of mpox in eastern Democratic Republic of Congo
The smallpox vaccine has been known to help prevent mpox due to the two viruses being closely related
In just the past few weeks cases of the new strain have been detected in Sweden and Thailand meaning it has now reached both Europe and Asia.
While no cases have yet been confirmed in the UK experts suspect the new variant is already in Britain as it can take over two weeks for symptoms like the classic skin lesions to develop.
But experts have said fatality rates for clade 1b from central Africa are unlikely to be replicated in developed nations due to better access to higher quality healthcare.
The UK Health Security Agency has cautioned it is ‘already planning’ for UK cases of the new strain.
Mpox typically causes characteristic lumpy lesions, as well as a fever, aches and pains and fatigue.
In a small number of cases, it can enter the blood and lungs, as well as other parts of the body like the brain which causes it to become life-threatening.
