A potent coronavirus variant originating in South Africa and found to be partly resistant to current vaccines and antibody treatments has been detected for the first time in the United States in two South Carolina patients, health officials said on Thursday.
Medical experts said arrival of the so-called South African variant presented an alarming new challenge in efforts to contain a raging pandemic that has claimed at least 430,000 American lives in 11 months, as authorities struggle to launch the largest mass-vaccination campaign in U.S. history.
All viruses mutate frequently, and scientists have identified several variants of the novel coronavirus found to be more transmissible than the original strain.
But the presence of the South African variant, which has shown no evidence of causing more severe disease, is nonetheless especially concerning because several laboratory studies have found that it reduces vaccine and antibody therapy efficacy.
Confirmation of two patients with that variant in South Carolina came days after the Minnesota Department of Health identified the first known U.S. case of another highly contagious strain that originated in Brazil.
Yet a third form of the virus from the UK that is more infectious, and associated with higher mortality, made its first U.S. appearance last month in Colorado and has since been detected in at least 28 states.
The flurry of variants taken together “have really changed the entire picture of the COVID-19 pandemic,” Dr. Michael Osterholm, director of the University of Minnesota’s Center for Infectious Disease Research and Policy, said in an MSNBC interview. “We’re now in by far the most dangerous period of the pandemic.”
The U.S. Centers for Disease Control and Prevention (CDC) has predicted the UK variant could become the dominant strain in the United States by March.
Dr. Anthony Fauci, the leading U.S. infectious disease specialist, told MSNBC all the new variants were worrisome, but “the one that is of greater concern and that really could be problematic is the mutant that is now dominant in South Africa.”
So far, the two-dose vaccines made by Moderna Inc and Pfizer Inc with BioNTech 22UAy.DE appear protective against the South African variant, despite a weaker immune response.
The companies said this week they were considering making new versions of their shots just in case. Moderna also plans to test giving a third shot of its vaccine to bolster antibody levels.