What Omicron means for future immunity
NEW DELHI: Millions around the world are now recovering from an Omicron variant infection, bringing into spotlight the immunity they may now have and whether this can protect against other configurations of the Sars-cov-2.
Three recent studies now come to similar conclusions on postomicron immunity: the protection is different in people who were infected for the first time, had a repeat infection, or had a repeat infection after vaccination.
More specifically, those who were immune naïve and got Covid-19 for the first time when they were infected with Omicron did not have antibodies that could effectively neutralise other variants, like Delta, Alpha and Beta.
In those who got a repeat infection but were unvaccinated, the antibodies were somewhat better at neutralising other variants.
The most superior antibody response was seen in those who had a past Delta infection as well as full doses of vaccines, and were infected by Omicron again. Antibodies in these people had a much superior ability to neutralise both variants, but particularly Delta.
“Hopefully, all this means Delta is on its way out as Omicron may shut the door on Delta re-infections, provided enough people vaccinate,” said Alex Sigal, research group leader at the Africa Health Research Institute, that carried out on of the studies. “The unvaccinated lose out on the extra Omicron protection and don’t gain a boost to Delta.”
The same findings were made by researchers at San Franciscobased independent research organisation Gladstone Institutes.
The Gladstone Institutes researchers write, “Omicron infection enhances pre-existing immunity”. But on its own, it “may not induce broad, cross-neutralising humoral immunity in unvaccinated individuals”.
The third study, from a team led by scientists at University of Washington, found that higher the number of doses and past exposure, the better the immunity. In fact, four exposures to the Sarscov-2’s spike protein -- an infection, two shots and booster -offered immunity that could also neutralise the first Sars virus.