Pfizer Covid vaccines may not fully protect against Omicron: Study

In an early investigation, researchers in South Africa discovered that Pfizer’s coronavirus vaccine (Covid-19) provided less immunity against the Omicron variation than to other major variants of the virus. When compared to the strain discovered in China almost two years ago, Omicron resulted in a 40-fold drop in neutralising antibodies produced by persons who had received two doses of the Pfizer-BioNTech SE injection in lab studies done at the Africa Health Research Institute in Durban.

Alex Sigal, the head of research at the laboratory, said that the loss of immune protection is “robust, but not complete” and that further efficacy studies are needed to appropriately take on board the exact extent of the vaccine’s impact in mitigating the disease caused by this new strain.

Speaking at an online presentation of the first reported experiments gauging the efficacy of the Pfizer Covid-19 vaccine against Omicron, Sigal said there will be “more breakthrough” of vaccine-induced immunity as he pushed the idea of getting booster shots to protect oneself against the new variant.

“A good booster probably would decrease your chance of infection, especially severe infection leading to more severe disease,” the Bloomberg news agency quoted the researcher as saying. “People who haven’t had a booster should get one, and people who have been previously infected should be vaccinated.”

Although these are early studies into the efficacy of existing vaccines against Omicron, the preliminary results have raised concerns that immune protection from vaccination or a previous bout of Covid-19 may be insufficient to stop reinfections or stem a fresh wave of cases and hospitalisations.

However, a top WHO official stated on Tuesday that there is no reason to believe that Omicron is more severe than previous strains or that existing vaccines will fail to protect against it. In an interview with AFP, Michael Ryan, the World Health Organization’s emergency director, said there is presently no evidence that existing vaccines will fail to protect those who get Omicron from the disease’s severe results.

A similar assurance was echoed on Tuesday by US infectious diseases expert Anthony Fauci, who said that Omicron is certainly not worse than the previous strains, including Delta.

However, both the experts agreed that more epidemiological data from around the world is needed to affirm scientific consensus on this. Since South Africa announced the discovery of Omicron on November 25, about 450 researchers globally have been working to isolate the variant from patient specimens, grow it in labs, verify its genomic sequence, and establish methods to test it in blood plasma samples, according to WHO.

Sigal’s laboratory was the first to isolate the Beta variant, a strain of the coronavirus that was identified in South Africa late last year. The latest research in his lab involved testing 14 blood plasma samples collected from a dozen people who had been given a second Pfizer-BioNTech shot about a month earlier to gauge the concentration of antibodies needed to neutralise or block the virus.