JOHANNESBURG, May 1 – Two new sublineages of the Omicron variant coronavirus can evade antibodies from previous infections well enough to trigger a new wave, but are far less able to thrive in the blood of people infected against COVID-19, South Africa scientists have found.
Scientists from multiple institutions studied Omicron sublines BA.4 and BA.5 – which the World Health Organization added to its watch list last month. They took blood samples from 39 participants who had previously been infected with Omicron when it first emerged late last year.
Fifteen were vaccinated – eight with Pfizer’s vaccine; seven with J&J’s – while the other 24 weren’t.
“The vaccinated group showed about a 5-fold greater neutralization capacity … and should be better protected,” says the study, a preprint of which was published over the weekend.
In the unvaccinated samples, there was a nearly eight-fold decrease in antibody production when exposed to BA.4 and BA.5 compared to the original BA.1 Omicron line. The blood of the vaccinated persons showed a three-fold decrease.
South Africa could be entering a fifth wave of COVID-19 sooner than expected, officials and scientists said on Friday, blaming a continued spike in infections apparently driven by Omicron subvariants BA.4 and BA.5.
Only about 30% of South Africa’s 60 million people are fully vaccinated.
“Based on the neutralization escape, BA.4 and BA.5 have the potential to lead to a new wave of infection,” the study states.
Editing by Frances Kerry