Pfizer and BioNTech said on Thursday that a recent trial suggests that protection from the companies’ COVID-19 vaccine lasts at least six months, and may also be effective against the coronavirus variant first found in South Africa.

The companies in a press release said data from a 12,000 person trial in South Africa, where the B.1.351 strain is prevalent, found that their vaccine was 100 percent effective at preventing cases of the disease.

The variant has raised concerns across the world, as it has proved to be resistant to some of the protections generated by therapeutics and vaccines. 

The trial also found that safety and efficacy of the vaccine hold up over time. There were no serious safety concerns observed in trial participants six months after being immunized, and overall effectiveness was more than 91 percent against disease with any symptoms for six months, the companies said.

“These data confirm the favorable efficacy and safety profile of our vaccine and position us to submit a Biologics License Application to the U.S. FDA,” Pfizer Chairman and CEO Albert Bourla said in a statement. “The high vaccine efficacy observed through up to six months following a second dose and against the variant prevalent in South Africa provides further confidence in our vaccine’s overall effectiveness.”

The data have yet to be peer-reviewed and published, but the companies said that they plan on submitting their findings to regulatory agencies around the world soon. Pfizer has said they aim to file for full approval in April. The vaccine is currently available under an emergency use authorization. 

“It is an important step to further confirm the strong efficacy and good safety data we have seen so far, especially in a longer-term follow-up,” Ugur Sahin, CEO and co-founder of BioNTech, said. “These data also provide the first clinical results that a vaccine can effectively protect against currently circulating variants, a critical factor to reach herd immunity and end this pandemic for the global population.”

In the U.S., nearly 77 million doses of the Pfizer and BioNTech coronavirus vaccine have been administered, making it the most widely used coronavirus vaccine.