COVID variants vs. vaccines

Porto Alegre, Brazil - The Pan American Health Organization (PAHO) detected three strains of SARS-CoV2 in Latin American countries, which had been reported in Brazil, the United Kingdom, and South Africa. Photo by Itamar Aguiar / Latin America News Agency.

The U.K. variant of COVID-19 is doubling every 10 days in the U.S., according to a report out Sunday. Dr. Anthony Fauci says this variant could become the dominant strain in the U.S. by the end of March. 

The U.S. has also seen worrisome mutations from South Africa and Brazil. What does this mean for vaccine rollout?