Scientists are rushing to develop a hantavirus vaccine as the number of confirmed infections grows – but experts have warned it could take years to be approved.
Researchers from the University of Bath say they are working on a ‘highly promising’ jab that is ‘completely new’.
To date, it has been tested in both the laboratory and in animal models, which have yielded ‘excellent immune responses’.
They said they expect to proceed to human trials in the near future.
However, researchers have warned approval could take years due to a lack of investment.
‘A major barrier for hantavirus vaccines is funding for advanced development,’ Jay Cooper, a virologist from the US Army Medical Research Institute of Infectious Diseases, told Nature.
‘Right now we are pushing from the research side, but there is no strong external pull, so progress is slower than it could be. It’s frustrating – like pushing a rock up a hill for years.’
It comes as the World Health Organisation (WHO) warned there could be more cases around the world, after the rat–borne virus hit a luxury cruise leaving three passengers dead.
Professor Asel Sartbaeva, from the University of Bath, is part of the team leading the vaccine development.
‘Currently there is no effective vaccine against Hanta viruses, leaving large populations in Southeast Asia, Africa and South America vulnerable to diseases that are originated and transmitted by rodents,’ she said.
‘Our team has developed a new antigen against Hantaan disease, from the Hanta virus group.
‘This is a completely new vaccine that has now been tested in the laboratory and in animal models, indicating excellent immune response.
‘While more work needs to be done to bring this vaccine to public – clinical trials and approvals – this is a very promising development of a completely new and needed vaccine.’
For a vaccine to be approved it has to go through several stages of testing for safety, dosage and effectiveness.
This starts with pre–clinical lab tests and, if successful, moves to three clinical trial phases which tests on increasing numbers of volunteers to compare vaccinated individuals against a control group.
Dr Cooper has been working on a hantavirus vaccine for more than three decades. His team have already completed phase one clinical trials for vaccines of Andes virus – the strain of hantavirus that has spread on the cruise ship.
This comes as more than 100 people remain trapped aboard a cruise ship infected with rat–borne hantavirus off the coast of Cape Verde. The infection has already killed three passengers, including a Dutch couple and a German national
The outbreak of the rare, rat–borne illness that has a 40 per cent mortality rate has left three people dead and several others seriously ill
Researchers from the University of Bath say they are working on a ‘highly promising’ jab that is ‘completely new’
While this may sound promising, he warned: ‘Because human cases of Andes virus are rare and geographically scattered, there is no obvious region to run a classic phase three efficacy trial, so to meet the requirements for licensing the vaccine requires more creative approaches.’
He explained that in humans, the Andes DNA vaccine induces neutralising antibodies, which are important for protection.
It works by training the immune system to produce specialised proteins that bind directly to the virus, physically blocking it from attaching to and infecting cells.
‘However, it requires at least three doses – a prime plus two boosters – instead of a single shot or simple prime–boost regimen,’ he added.
Once approved, likely recipients would be people travelling to regions where the virus is endemic, outdoorspeople and others with high exposure to rodent habitats, military personnel and workers in fields with heavy rodent contact.
‘Overall, the commercial market would be small, and it is not an attractive vaccine market from a pure business perspective,’ he added.
Bath University’s vaccine is being developed using, in part, mRNA technology.
This is the same that was used for the rapid development and rollout of the Covid vaccine.
Covid vaccines were developed and deployed at massive scale very quickly to help combat the global pandemic.
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Meanwhile hantavirus is much rarer and WHO scientists have said they don’t expect it to cause an epidemic – meaning its development and deployment is expected to be much slower.
This morning, health officials announced a third British national has been diagnosed with suspected hantavirus linked to the MV Hondius cruise ship outbreak.
The patient remains on the remote South Atlantic island of Tristan da Cunha, while the other two British nationals remain in hospital in the Netherlands and South Africa.
Speaking during a press briefing from Geneva on Thursday, WHO Director–General Dr Tedros Adhanom Ghebreyesus said that five of the eight suspected cases of hantavirus linked to the MV Hondius cruise ship have now been confirmed.
He said that the WHO was aware of reports of other patients and that there may be more cases due to the long incubation period of the virus.
‘Given the incubation period of the Andes Virus, which can be up to six weeks, it’s possible that more cases may be reported,’ he added.
