Johannesburg: A small South African study released Tuesday shows that Omicron infection may enhance immunity against the Delta variant of the coronavirus. The research, which has not yet been peer-reviewed, initially examined 15 people infected with Omicron. Some of these people were vaccinated while others were not.
The scientists then took samples to see if those people would be able to neutralise Omicron and Delta 14 days later. Two cases were excluded from the study at this stage due to a lack of ability to neutralize Omicron at either the start or end of the research.
Scientists found in the remaining 13 cases a 14-fold increase in ability to neutralise Omicron, as well as a 4.4-fold increase in ability to neutralise the Delta variant of the virus.
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The study noted that some of the participants were vaccinated and many were also likely to have been previously infected with an earlier strain of the virus, meaning that the neutralisation of Delta could not be definitively attributed to the Omicron infection.
“Participants in this study have likely been previously infected, and more than half were vaccinated. Therefore, it is unclear if what we observe is effective cross-neutralization of Delta virus by Omicron elicited antibodies, or activation of antibody immunity from previous infection and/or vaccination,” the study said.
Seven of the individuals in the study were vaccinated — three with two doses of Pfizer, three with one dose of Johnson & Johnson, and one with two doses of Johnson & Johnson.
Eleven of the original 15 participants were hospitalised for Covid-19, but none required supplementary oxygen treatment.
The study was led by Alex Sigal, a researcher at Africa Health Research Institute who was born in the then-Soviet Union and grew up in Israel, where he studied at the Weizmann Institute of Science in Rehovot.
“The increase neutralizing immunity against Omicron was expected – that is the virus these individuals were infected with,” Sigal tweeted. “However, we also saw that the same people – especially those who were vaccinated – developed enhanced immunity to the Delta variant,” he added.
Sigal said that if Omicron causes less severe disease, as researchers are cautiously saying, then the newer variant could help to displace Delta as the dominant strain if those infected with Omicron are then less likely to catch the earlier variant. “If that’s true, then the disruption Covid-19 has caused in our lives may become less,” Sigal informed.
