LONDON — A peer-reviewed scientific study published on Wednesday says known mutations of the SARS-CoV-2, or coronavirus, do not increase virus transmissibility.

Researchers also say the mutations do not pose a threat to vaccine efficacy. Viruses mutate, or change, constantly and some, like the flu, mutate more than others. The COVID-19 virus is also mutating while it spreads, but the researchers found that none of the mutations they have found appear to be making the virus spread faster.

The study was conducted at Britain’s University College London, Oxford University and France’s Cirad and Université de la Réunion and used a global dataset of virus genomes from 46,723 people with COVID-19 from 99 countries. The scientist identified more than 12,700 mutations in the SARS-CoV-2 virus.

“The news on the vaccine front looks great,” UCL professor Francois Balloux told Reuters. “The virus may well acquire vaccine-escape mutations in the future, but we’re confident we’ll be able to flag them up promptly, which would allow updating the vaccines in time if required.”

The researchers found that of more than 12,706 mutations identified, some 398 appeared to have occurred repeatedly and independently. Of those, the scientists focused in on 185 mutations, which they found had occurred at least three times independently during the course of the pandemic.

In the U.S., vaccines could begin reaching millions of people shortly after the U.S. Food and Drug Administration (FDA) rules on its emergency use authorization on Dec. 10. That vaccine was developed by Pfizer, which has begun rehearsed dry-runs of distribution.

Dr. Moncef Slaoui, the chief scientific adviser for the government’s “Operation Warp Speed” vaccine program, said earlier this week that first Americans could receive a COVID-19 vaccine as soon as 24 hours after the FDA grants approval.

6.4 million doses of the COVID-19 vaccine could be released nationwide in an initial distribution after the FDA approval. States will be in charge of how the vaccine will be distributed to their populations.