The Pfizer vaccine was able to neutralize a coronavirus variant first identified in Brazil in a new lab study, a positive sign for the vaccine’s effectiveness.

Neutralization of the Brazilian variant, known as P.1, was “roughly equivalent” to the original strain of the virus, which the Pfizer vaccine has been shown to be highly effective against, researchers wrote in a letter to the New England Journal of Medicine.

The P.1 variant has provoked some concern given the surge in cases it is fueling in Brazil.

Anthony FauciAnthony FauciReaching immunity: A path forwardRepublicans call for investigation into impact of school closures on children with disabilitiesThe Hill’s Morning Report – Presented by the National Shooting Sports Foundation – Relief bill to become law; Cuomo in troubleMORE, the top US infectious disease expert, said in a presentation last week there are “preliminary reports” the variant is more infectious, and that antibodies produced by vaccines “may be less effective.” 

The results published Monday from researchers from Pfizer, its German partner BioNTech, and the University of Texas Medical Branch, however, are reassuring. 

The study also found strong neutralization of the B.1.1.7 variant, first identified in the U.K., though that was already expected. 

The B.1.351 variant, first identified in South Africa, has been perhaps the most concerning variant, for its potential ability to weaken the effectiveness of vaccines to some degree. The study found neutralization of that variant was “robust but lower.” 

“We see high neutralizing activity against all strains tested, including P.1 that is spreading so rapidly in Brazil,” Carl Bergstrom, a professor of biology at the University of Washington, tweeted in response to the study. “While activity is diminished against the B.1.351 strain from South Africa, it is still very impressive.” 

The study authors cautioned that their results are based on a study in a lab and must ultimately be validated by real-world evidence.