Hantavirus, progress and challenges in vaccine development: promising data but obstacles remain

The Hantavirus outbreak on the cruise ship Mv Hondius now arriving in Tenerife to disembark passengers has relaunched the race for a vaccine against this virus that currently doesn't exist but may arrive soon.

In addition to the interest of the Moderna company, which is already the protagonist of the anti-Covid made in record time in 2020, there are, however, those who are already working on the vaccine against the various hantaviruses. It is Jay Hooper, a virologist at the Us Army Medical Research Institute of Infectious Diseases in Frederick (Maryland), who spoke to Nature and explained how 'the Phase I data for the vaccine are promising, but there are several hurdles to getting it produced'.

But why is the Hantavirus back in the limelight today? "Some have speculated, and I myself think so, that climate change could alter rodent populations and increase the number of people living in or entering areas where these rodents are present. This could increase the number of cases,' Hooper replied.

How long has your team been working on hantavirus vaccines? 'Because these viruses are transmitted by rodents and pose a risk to troops in the field, the army has been aiming for a vaccine for some time. I,' explains the virologist, 'have been working at the US Army Medical Research Institute for Infectious Diseases, which has been working on vaccines against the hantavirus since about the 1980s. I joined the team in the 1990s. At that time, new hantaviruses responsible for hantavirus pulmonary syndrome (HPS) appeared: the Sin Nombre virus' the one responsible for the death of actor Gene Hackman's wife, who later also died 'in the Four Corners region of the US and the Andes virus in South America. The laboratory began to develop vaccines for these species'.

Today, the work of Hooper's team is well advanced, 'we have developed a realistic animal model to test vaccines starting with hamsters,' he continues. 'We have conducted Phase I clinical trials on vaccines for the Andes virus and two other species, Hantaan and Puumala. In humans, the DNA vaccine against the Andes virus induces neutralising antibodies, which are important for protection, so the vaccine looks promising. However, it requires at least three doses (one initial plus two booster doses) rather than a single injection or a simple booster dose. We are now taking neutralising antibodies from vaccinated human subjects and testing them as a vaccine in the hamster model; the results will be published in the future'.