SAN DIEGO (KGTV) – This week scientists detected the first cases of the South African variant in California, a version of the coronavirus that seems most elusive for current vaccines and the natural immunity produced by previous infections.
The South African variant shares a mutation with the UK variant that scientists believe makes the virus more sticky to cells and more transmissible. The South African variant, officially known as B.1.351, also has two other mutations in its tip proteins that scientists consider worrisome.
Researchers pay close attention to the virus’s flagship proteins because they allow the pathogen to attach to cells. Spike is also the target protein of the current generation of COVID-19 vaccines.
All current vaccines train the immune system to build antibodies by introducing fake spike proteins. These harmless impostors are designed to look like the pointed knobs on the surface of the actual coronavirus.
But the South African variant has small mutations in its peaks that make it harder to block some antibodies, based on early research.
“The whole peak does not change shape. What happens is a small knob or piece (we call it an epitope) to which specific antibodies bind so that they no longer bind, ”said Doug Richman, a doctor of medicine at the University of San Diego.
A study by Moderna that used blood samples found that the antibodies produced by her vaccine were six times less effective against the South African variant.
There have also been several confirmed cases of COVID survivors reinfected with the variant. A vaccine study in South Africa found new infections in 2% of people who had been infected with an earlier version of the virus.
In general, the second infections are usually milder than the first, Richman noted.
He also stressed that vaccines have shown promising results in their ability to prevent serious diseases caused by the variant, even if they cannot completely prevent symptoms.
“What will happen is that someone who has a life-threatening infection or requires hospitalization will have a milder infection,” he said.
The South African variant is different from the UK variant, which has been detected in approximately 1,000 people in the United States.
The UK variant, B.1.1.7, currently accounts for approximately 1 to 2 percent of infections in the United States, but is spreading rapidly. A study by Scripps Research estimates that it doubles every 10 days and will become the dominant strain in this country by the end of March.
The two variants share a mutation that makes the virus more sticky, known as N501Y. This scientific abbreviation means that at position 501 of amino acids in the viral sequence, an “N” (the abbreviation for asparagine) was replaced by a “Y” (the abbreviation for tyrosine).
But the South African variant contains two other mutations, E484K and K417N, which appear to help it escape, Scripps researcher Karthik Gangavarapu said.
“These mutations together, the end result is that it is able to escape immunity,” he said.
Gangavarapu is part of the lab that detected the UK variant in San Diego. He said so far they have not detected the South African variant in their samples.