SAN DIEGO (KGTV) – Scientists this week discovered the first cases of the South African variant in California, a version of the coronavirus that seems more elusive to current vaccines and the natural immunity caused by previous infections.
The South African variant shares a mutation with the British variant that scientists believe makes the virus stickier to cells and more transmissible. The South African variant, known officially as B.1.351, also has two other mutations in its spike proteins that scientists consider troubling.
Researchers are paying close attention to the spike proteins on the virus because they allow the pathogen to stick to cells. Spike is also the protein targeted by the current generation of COVID-19 vaccines.
All current vaccines train the immune system to build antibodies by introducing fake proteins. These harmless tricksters are designed to look just like the spiky buds on the surface of the actual coronavirus.
But the South African variety has tiny mutations in its peaks that make it harder for some antibodies to lock up, based on early research.
‘The entire peak doesn’t change shape. What happens is a tiny button or piece – we call it an epitope – that specific antibodies bind to is changed so that they no longer bind, ”said UC San Diego virologist Dr. Doug Richman.
A Moderna study of blood samples found that antibodies produced by the vaccine were six times less effective against the South African variety.
There are also several confirmed cases of COVID survivors re-infected with the variant. A vaccine study in South Africa found new infections in 2 percent of people infected with an earlier version of the virus.
In general, second infections are typically milder than the first, Richman noted.
He also emphasized that the vaccines have shown promising results in their ability to prevent serious illness caused by the variant, even if they cannot completely prevent symptoms.
“What’s going to happen is someone who would have a life-threatening infection or a hospitalization will get a milder infection,” he said.
The South African variety is different from the British variety, which has been found in about 1,000 people in the United States.
The British variant, B.1.1.7, is currently responsible for about 1 to 2 percent of infections in the United States, but is spreading quickly. A study by Scripps Research estimates that it doubles in cases every 10 days and will become the dominant species in this country by the end of March.
The two variants share a mutation that makes the virus stickier, known as N501Y. That scientific shorthand means that at the 501st amino acid position in the viral sequence, an “N” (the abbreviation for asparagine) was replaced with a “Y” (the abbreviation for tyrosine).
But the South African variant contains two other mutations, E484K and K417N, that appear to help it escape, Scripps researcher Karthik Gangavarapu said.
“These mutations put together, the end result is that it can escape immunity,” he said.
Gangavarapu is part of the laboratory that discovered the British variant in San Diego. He said so far they have not found the South African variant in their samples.