New Omicron sub-variants can dodge immunity from past infection: Study

Johannesburg: In the latest study, scientists in South Africa have found that two new sub-variants of the Omicron variant of the coronavirus can dodge the immunity present in the human body.

However, the relief is that for those who have got the vaccine, this sub-variant are far less able to thrive in the blood of people vaccinated against COVID-19.

The scientists from multiple institutions were examining Omicron's BA.4 and BA.5 sublineages - which the World Health Organization last month added to its monitoring list. They took blood samples from 39 participants previously infected by Omicron when it first showed up at the end of last year.

Fifteen were vaccinated - eight with Pfizer's shot, seven with J&J's -- while the other 24 were not.

"The vaccinated group showed about a 5-fold higher neutralisation capacity ... and should be better protected," said the study, a pre-print of which was released over the weekend.

In the unvaccinated samples, there was an almost eightfold decrease in antibody production when exposed to BA.4 and BA.5, compared with the original BA.1 Omicron lineage. Blood from the vaccinated people showed a threefold decrease.

South Africa may be entering a fifth COVID wave earlier than expected, officials and scientists said on Friday, blaming a sustained rise in infections that seems to be driven by the BA.4 and BA.5 Omicron sub-variants.

Only about 30% of South Africa's population of 60 million is fully vaccinated.

"Based on neutralization escape, BA.4 and BA.5 have the potential to result in a new infection wave," the study said.