New sub-lineage of Omicron variant able to evade immune system
New laboratory research shows that the BA.4 and BA.5 strains are able to evade both the natural immune response that comes from infection and the “barrier” created by COVID-19 vaccination.
According to Bloomberg news site, last April, South African scientists discovered two new sub-lines BA.4 and BA.5 ofOmicron variantat a time when the number of COVID-19 cases increased suddenly.
A new lab study shows that these variants are able to evade both the natural immunity gained after infection and the "barrier" created by COVID-19 vaccination.
The study was conducted at the Africa Health Research Institute laboratory in Durban with 24 people who had been infected with the original Omicron variant of the SARS-CoV-2 virus but had not been vaccinated against COVID-19 and 15 people who had been vaccinated.
Blood samples collected showed that in people who had been infected with Omicron, the amount of neutralizing antibodies decreased by nearly 8 times when tested against the BA.4 and BA.5 sub-variants. For those who had been vaccinated, the amount of neutralizing antibodies decreased by about 3 times during the same test.
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| Microscopic images provided by the US National Institute of Allergy and Infectious Diseases show SARS-CoV-2 virus particles in a sample of a COVID-19 patient. Photo: AFP/TTXVN |
However, the amount of these antibodies is extremely low in unvaccinated people. Therefore, this group is unlikely to be resistant to the two new sub-variants, thereby potentially posing a risk that BA.4 and BA.5 could cause a new wave of infection.
The findings come amid a surge in new cases in South Africa, which is experiencing its first wave of COVID-19 cases caused by the Omicron variant after it was first detected there and in neighboring Botswana.
The Africa Health Research Institute's research lab was the first to test for the original Omicron variant of the SARS-CoV-2 virus based on blood sample analysis.
