Pfizer Covid-19 jabs protective against Beta, Gamma variant
US pharmaceutical Pfizer's vaccine against Covid-19 can effectively neutralise Beta, Gamma variant of the Coronavirus disease, according to a study. The study led by researchers from the New York University, US, showed that the Pfizer BNT162b2 vaccination worked well against the majority of variants as the earlier virus, but the vaccine neutralised the South African variant and the Brazil variant with a 3-fold decrease in titer.
"Our interpretation of the results is that the vaccine antibodies are very powerful, and even if you lose 3-fold of the titer, there is still plenty of antibody there to neutralize the virus. We believe the findings demonstrate that the vaccines will remain protective against the variants that we tested," said Nathaniel "Ned" Landau, Professor in the Department of Microbiology at the NYU Grossman School of Medicine, in New York City.
The study, published in the journal mBio, also found that monoclonal antibody cocktail consisting of casirivamab and imdevimab might be less effective against SARS-CoV-2 variants in laboratory experiments.
Lab experiments on Regeneron pharmaceuticals' REGN-COV2 -- a 2 recombinant monoclonal antibody cocktail -- showed that casirivamab had lost some of its neutralising activity against the South African and Brazilian variants and the cocktail was 9- to 15-fold decreased in titer, the team said.
"One of the Regeneron antibodies is affected by the E484K mutation, and as a result the cocktail loses some of its neutralizing activity," said Landau.
"The question with this work is 'how do the laboratory findings translate into clinical effects, that is what will happen when you treat a patient infected with one of the variants?' We cannot say for sure. We will only know when the clinical data comes in," Landau noted.
The team created a panel of pseudotyped viruses using the spike proteins from six different variants of SARS-CoV-2: the B117 lineage variant identified in the UK, the B1351 lineage variant identified in South Africa, the B11248 lineage variant identified in Brazil, the COH.20G/677H lineage variant identified in Columbus Ohio, the 20 EUs variant identified in Spain and later found elsewhere in Europe, and the Mink cluster five spike proteins located in minks in Denmark.
Similar experiments in Moderna's Covid vaccine also produced the same results, Landau said.
ALSO READ | Pfizer, Moderna vaccines can reduce COVID risk by 91 per cent: US CDC
ALSO READ | US to buy 500M Pfizer vaccines to share globally
