Contracting Omicron may not significantly raise vaccinated patient’s immunity against Delta: doctor
It may be too soon to be excited by findings by South African scientists that patients who had been vaccinated against Covid-19 and then contracted Omicron had developed significantly stronger immunity against the Delta variant, said Dr Anan Jongkaewwatana from the National Centre for Genetic Engineering and Biotechnology.
In a Facebook post on Thursday, Anan said the South African study titled “Omicron infection enhances neutralising immunity against the Delta variant”, which has not been peer-reviewed, could be inconclusive due to too small a number of examples – only 13.
“I have reviewed another study by Hong Kong scientists among only two candidates who contracted Omicron after they had been vaccinated with two doses of mRNA vaccines,” he said. “The result showed that the first candidate had improved neutralising immunity against Delta 9.58 times higher than unvaccinated persons. However, in the second candidate, the Delta immunity went up only 1.42 times,” Anan said.
“This indicates that after contracting Omicron, a patient’s immunity against Delta is still not significantly higher than that of unvaccinated people,” he pointed out.
“The South African study is indeed interesting, but we still need more extensive studies before we can conclude that contracting Omicron could serve as nature’s immunity boost against other variants,” Anan added.