Hantavirus has no cure. What do we know about potential vaccines?

The world is currently in a tizzy over the hantavirus.

At least three people have died after an outbreak on the MV Hondius cruise ship, and another eight have been infected. Now, with the last passengers deboarding the cruise ship and at least three new cases linked to the outbreak, many are wondering about a possible hantavirus vaccine.

The Andes virus, which is at the centre of the recent outbreak, is the strain that shows the most reported cases of human-to-human transmission. It usually occurs in South American countries like Argentina.

As of this moment, there is no approved vaccine or antiviral drug for hantavirus. Patients can only be given supportive care.

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But what do we know? When will such a vaccine be ready?

Let’s take a closer look.

What we know

According to Bloomberg, the Biotech firm Moderna in a statement, said that it has conducted early-stage vaccine research on hantaviruses alongside the US Army Medical Research Institute of Infectious Diseases. Moderna is also partnering with the Vaccine Innovation Center at Korea University College of Medicine on a potential cure. It said the research was ongoing prior to the outbreak aboard the Hondius.

“These efforts are early-stage and ongoing and reflect Moderna's broader responsibility to develop countermeasures against emerging infectious diseases,” the company said in a statement.

Moderna isn’t alone. According to the BBC, researchers from the University of Bath have developed a new antigen against Hantaan, which is a kind of hantavirus. Professor Asel Sartbaeva, a co-founder of EnsiliTech, a UK-based biotech company, told the outlet the vaccine is displaying an “excellent immune response”. However, Sartbaeva added that it is yet to go through clinical trials and approvals before it is rolled out to the public.

A Spanish passenger is sprayed with disinfectant by Spanish government officials before boarding a plane after disembarking from the hantavirus-stricken cruise ship MV Hondius at Tenerife airport in the Canary Islands, Spain. AP

EnsiliTech has been working on hantavirus for a decade and a half, as per NBC News. It uses mRNA technology, the same as the Covid-19 jabs. “We looked at hantavirus and saw it was pretty neglected,” Matt Slade, a company co-founder and its chief of staff, told the outlet. “There wasn’t really any work in the sector.” It has come up with a process known as “ensilication”, which surrounds the mRNA in a protective silica cage.

According to The New York Times, Jay Hooper, a virologist at the US Army Medical Research Institute of Infectious Diseases in Maryland’s Frederick, and his colleagues have been working on a DNA vaccine for the Andes version of the hantavirus. This has shown some success in a Phase 1 trial. Hooper said in some cases over 80 per cent of participants produced antibodies. “It’s pretty amazing,” Hooper, who has been working on the virus since 1990, said. “Getting these kinds of neutralising antibodies in humans is impressive.”

However, the potential vaccine requires at least three doses. But Hooper was confident that it can be pushed ahead “if there’s a need”. “We’ve done the science. It’s just other forces that are required to move vaccines forward — markets, government demand,” Hooper said.

When will it be ready?

Experts say it could likely take years before any hantavirus vaccine is ready for public use.

Hooper explained why. “It’s not an airborne, highly contagious viral threat, so it hasn’t been as high a priority for groups trying to prevent pandemics,” Hooper told The New York Times.

Sabra Klein, a professor in the molecular microbiology and immunology department at the Johns Hopkins Bloomberg School of Public Health, agreed. “Our funding agencies don’t put a lot of money into this, because it’s likely not to cause the next epidemic or pandemic,” Klein told NBC News. “But these are haemorrhagic fever viruses, so when they occur, they’re scary, and they do wreak havoc.”

Passengers wave inside a bus after being disembarked from the hantavirus-stricken cruise ship MV Hondius at the port of Granadilla in Tenerife, Canary Islands, Spain on Sunday. AP

Slade explained that one of the reasons the research is taking so long is that scientists want to ensure that a hantavirus vaccine can be transported at room temperature. The Covid-19 vaccines by Moderna and Pfizer needed to be transported via cold storage. While the company has successfully carried out trials on rodents, it has not done so on humans. Early-stage clinical trials could take another three to four years. Slade said that EnsiliTech could take another five years to come up with the final version of the vaccine.

This is if the government does not greenlight an operation similar to Warp Speed for Covid. “As was the case with Covid, that can be shortened quite significantly because you get emergency access and emergency approval,” Slade said. “But if everything stays as with typical vaccine development, that’s what we would expect to see.”

Others are a little more optimistic.

“I do think there are things that are sitting there on the bench that could be quickly developed,” Dr Ronald Nahass, the president of the Infectious Diseases Society of America, told The New York Times. “But nothing is ready.”

But Slade remained more cautious. “There has to be a strong commercial case for these vaccines,” he told NBC News. “Unfortunately, hantaviruses tend to be endemic in parts of the world that don’t really have that financial backing, so I think there’s just been a lack of interest.”

Which is why the world will be praying that a Covid-19-like scenario can be avoided.

FAQs

1. Is there a vaccine for hantavirus currently available?

No, there is currently no approved vaccine or antiviral treatment for hantavirus. Patients receive supportive care.

2. How long could it take to develop a hantavirus vaccine?

Experts suggest it may take several years, with early-stage clinical trials alone expected to take three to four years.

3. Why has hantavirus vaccine development been slow?

Funding and priority have been limited because hantavirus is not highly contagious and is unlikely to cause a global pandemic, reducing urgency compared to diseases like Covid-19.

With inputs from agencies