SAN DIEGO (KGTV) – Scientists this week detected the first cases of the South African variant in California, a version of the coronavirus that appears to be more evasive than current vaccines and the natural immunity produced by previous infections.
The South African variant shares a mutation with the British variant, which scientists believe makes the virus more sticky and more transmissible. The South African variant, officially known as B.1.351, has two other mutations in its peak proteins, which scientists consider worrying.
Researchers pay special attention to the virus’s peak proteins because they allow the pathogen to cling 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 spike proteins. These harmless impostors are designed to look exactly like the spiky buttons on the surface of the actual coronavirus.
But the South African variant has small mutations in its tips, which make it more difficult to block antibodies, based on early research.
“The whole peak does not change its shape. What happens is a small button or piece – we call it an epitope – that specific antibodies bind to changes so that they no longer bind, “said Dr. Doug Richman, a UC San Diego virologist.
A study by Moderna using blood samples found that the antibodies produced by her vaccine were six times less effective against the South African variant.
There were also several confirmed cases of COVID survivors who were re-infected with the variant. A South African vaccine study found new infections in 2% of people who were infected with an earlier version of the virus.
In general, the second infection tends to be milder than the first, Richman noted.
He also pointed out that vaccines have shown promising results in their ability to prevent severe 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 hospitalization is needed will have a milder infection,” he said.
The South African variant is distinct from the United Kingdom variant, which was detected in approximately 1,000 people in the United States.
The British variant, B.1.1.7, currently accounts for about 1-2 percent of infections in the United States, but is spreading rapidly. A study by Scripps Research estimates that it doubles in cases 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 transcript means that at position 501 of the amino acids in the viral sequence, an “N” (abbreviation for asparagine) has been replaced with a “Y” (abbreviation for tyrosine).
But the South African version contains two other mutations, E484K and K417N, which appear to help it escape, said Scripps researcher Karthik Gangavarapu.
“These mutations put together, the end result is that it is able to get rid of immunity,” he said.
Gangavarapu is part of the laboratory that detected the British version in San Diego. He said so far they had not detected the South African variant in their tests.