The coronavirus isn’t mutating very quickly as it spreads — which means a vaccine could potentially provide years of protection, according to a report.

Peter Thielen, a molecular biologist with Johns Hopkins University Applied Physics Laboratory, told the Washington Post. that the strains currently in US only have seen around four to 10 genetic variations since the outbreak in Wuhan, China,

“That’s a relatively small number of mutations for having passed through a large number of people,” Thielen said. “At this point the mutation rate of the virus would suggest that the vaccine developed for SARS-CoV-2 would be a single vaccine, rather than a new vaccine every year like the flu vaccine.”

Stanley Perlman, a virologist at the University of Iowa, agreed that the virus appears to be fairly stable compared to other illnesses.

“The virus has not mutated to any significant extent,” Perlman told the newspaper.

But other experts said that that only time will tell whether the virus will require a one-time shot for protection, which is the case with the measles.

“Just one ‘pretty bad’ strain for everybody so far. If it’s still around in a year, by that point we might have some diversity,” Benjamin Neuman, a virologist with Texas A&M University at Texarkana, told the Washington Post.

The coronavirus had infected more than 436,000 people across the world as of Wednesday, causing around 20,000 deaths, according to the latest figures from the John Hopkins University.