A South African study based on blood samples found that the BA.4 and BA.5 sublineages of Omicron were more likely to evade antibodies produced by previous Omicron infections than the immunity provided by vaccinations.
Scientists took blood samples from 39 people infected with Omicron, with 24 people not vaccinated and 15 vaccinated with the Pfizer or the Johnson & Johnson vaccines, Reuters reported.
“The vaccinated group showed about a fivefold higher neutralization capacity ... and should be better protected,” the investigators found, according to Reuters.
There was an eightfold decrease in antibody protection in unvaccinated blood samples when exposed to the subvariants compared to a threefold decrease in the blood samples from vaccinated people.
“Based on neutralization escape, BA.4 and BA.5 have potential to result in a new infection wave,” the investigators found.
The finding is important because health authorities say cases caused by the sublineages are increasing in South Africa to a degree that the nation may be entering a fifth wave of COVID, Reuters said.
Health Minister Joe Phaahla said recently that hospitalizations were increasing but that ICU admissions had not greatly gone up yet.
A version of this article first appeared on WebMD.com.