U.S.-based biotech company Novavax on Thursday said a COVID-19 vaccine showed nearly 90% effectiveness in late-stage clinical trials in the U.K. as well as strong protection against the variant.

Novavax announced in July that it was awarded $1.6 billion by the U.S. government to complete development for 100 million doses and is expected to be available in 2021. The British government has ordered 60 million doses. Novavax's vaccine still needs FDA authorization.

The company, however, found that the vaccine was only about 50% effective against the fast-spreading variant that is circulating in South Africa. 

There have been worries that the vaccines won't protect against these altered versions of the virus. Both Pfizer and Moderna recently stated that their COVID vaccines are less effective against the South African variant. Along with the U.K., there is a variant from Brazil. 

Two cases of the South African variant have just been identified this week in South Carolina. Both people in South Carolina have no recent travel history.

The Centers for Disease Control and Prevention released a statement Thursday that there is "no evidence that infections from the [South African] variant cause more severe disease."

“Like the UK and Brazilian variants, preliminary data suggests [the South African] variant may spread more easily and quickly than other variants,” the CDC said.

Dr. Anthony Fauci said this week that, "We are more concerned about the South African strain right now because when you do studies in the test tube, in vitro studies, it shows that the ability of monoclonal antibodies that have been used for therapy  -- that is really impaired in the presence of these particular variants. In other words, these monoclonal antibodies don't nearly work as well as treatment."