Pfizer's Covid-19 vaccine 40 times less effective against Omicron than to other strains: Study

Johannesburg: Researchers in South Africa have found in an early study that Pfizer's mRNA-based Covid vaccine may be up to 40 times less effective against the new super mutant Omicron variant.

In lab experiments conducted at the Africa Health Research Institute in Durban, it was observed that Omicron resulted in about a 40-fold reduction in antibodies generated by the Pfizer vaccine to neutralise the new variant compared with the original virus.

The findings from the study come at a time when health experts all around the world have raised concerns that the Omicron variant will have considerable escape from vaccine elicited immunity, based on the large number of mutations in the spike protein and elsewhere on the virus.

A team of scientists including Prof. Alex Sigal from the Africa Health Research Institute tested 14 plasma (blood) samples from 12 participants, with 6 having no previous record of SARS-CoV-2 infection and all who had previously been vaccinated with the Pfizer/BioNTech vaccine.

However, Prof Alex Sigal, a virologist at the Africa Health Research Institute, who led the research noted that Omicron's ability to escape vaccine antibodies is "incomplete."

Five of the participants, all previously infected, showed "relatively high neutralisation titers with Omicron".

The study showed that Omicron is much better at evading protection as vaccine-induced antibodies dropped three-fold in their ability to neutralise the earlier beta variant that previously dominated South Africa.

However, according to the World Health Organisation (WHO) existing vaccines should still protect people who contract the Omicron variant from severe Covid cases.

Dr Mike Ryan,WHO emergencies director said there was no sign Omicron would be better at evading vaccines than other variants, BBC reported.

Meanwhile top US infectious disease expert Anthony Fauci said that early data on the Omicron Covid-19 variant is a "bit encouraging" and does not indicate a great degree of danger, says.

"Though it's too early to really make any definitive statements about it, thus far it does not look like there's a great degree of severity to it," Fauci was quoted as saying to CNN.

"Thus far, the signals are a bit encouraging. But we have really got to be careful before we make any determinations that it is less severe, or it really doesn't cause any severe illness, comparable to Delta," he added.