A study performed by South African scientists among multiple institutions has analyzed the blood samples from nearly 40 participants who were once infected by Omicron as it first began to emerge towards the end of last year.

The study found that two new sub-lineages of the variant are capable of avoiding antibodies from earlier infection well enough to trigger a possible new wave. The variants, however, are far less able to thrive in the blood of people vaccinated, Reuters reported quoting the scientists. Last month, the sub-lineages were added to the list of monitorization by the WHO.

Among the participants of the study, 15 were vaccinated while 24 were not. "The vaccinated group showed about a 5-fold higher neutralization capacity... and should be better protected," Reuters quoted the study.

In those unvaccinated, there is a nearly eight-time decrease in antibody production when exposed to the sub-lineages compared to the original lineage. Blood from the vaccinated participants shows a three-time decrease. The findings come as South Africa is on the brink of entering its fifth wave of Covid the scientist said. They are blaming a sustained rise in infections that seem driven by Omicron sub-variants.

Only about 30% of South Africa’s population is fully vaccinated. “Based on neutralization escape, BA.4 and BA.5 have the potential to result in a new infection wave," the study concluded.