BackPfizer, Moderna vaccines show limited effectiveness on strain in India
A note from the World Health Organization said preliminary laboratory studies awaiting peer review suggest a limited reduction in neutralization by antibodiesIt added that real-world impacts may be limited
PremiumNEW DELHI : Preliminary laboratory studies of the mRNA vaccines by Pfizer and Moderna have shown decreased effectiveness against the double mutant variants discovered in India, the World Health Organization said in a note. This comes on the back of the multilateral agency classifying the mutated virus strain, B.1.617, as a variant of concern.
“Preliminary laboratory studies awaiting peer review suggest a limited reduction in neutralization by antibodies; however, real-world impacts may be limited," WHO said in its note.
The WHO’s note was primarily describing the characteristics of the B.1.617, which was earlier this week categorized as a "variant of concern", meaning that the mutant strain and its sublineages (B.1.617.1, B.1.617.2 and B.1.617.3) appear to have higher rates of transmission, including observed rapid increases in prevalence in multiple countries. So far, the strain has been found in 44 countries after first being discovered in Maharashtra in October.
To be sure, while laboratory data suggests these vaccines may see lower effectiveness against the mutant strain, the issue remains inconclusive until studies in real-world settings are conducted.
The global health agency cited three studies, all of which are awaiting peer review, that showed that antibodies generated by the vaccines developed by Pfizer and Moderna had significant reduction in the ability to neutralize the mutant virus and its sublineages.
On the other hand, it cited another non-peer reviewed study that showed that Covaxin was largely effective against the mutant strain of the virus.
One of the studies was jointly conducted by researchers from Emory University School of Medicine in Georgia, US, Stanford University School of Medicine and Vaccine Research Center of US’ National Institute of Allergy and Infectious Diseases. The study conducted tests on blood serum of 24 people who had recovered from covid-19, 15 people vaccinated with Moderna’s vaccine and 10 with Pfizer’s vaccine.
The study concluded that, when compared with the original strain isolated in the US, the variant from India was nearly seven-fold less susceptible to neutralization by blood serum from people who have earlier been infected with covid-19 or those vaccinated with either jabs. However, despite more resistance from the mutant strain, the majority of the sera from infected individuals and all vaccinated individuals were still able to neutralize the variant, the study said.
The other study cited by WHO was conducted by the University of Cambridge, India’s National Centre for Disease Control and CSIR Institute of Genomics and Integrative Biology, which also showed reduction in neutralizing activity generated by the vaccine against the virus.
The third study cited by the agency was conducted by researchers in Germany, who reported an approximately three-fold decrease in neutralization activity by plasma from 15 recipients of Pfizer’s against the Indian variant, and a limited two-fold decrease by convalescent sera from cases with severe covid-19.
The three studies come at a time when the Indian government has agreed to provide a fast-tracked clearance process for vaccines already authorized by regulators from the US, UK, Japan and European Union as well as WHO. The Indian regulator has also allowed states and private entities to directly import these vaccines even before it gets authorization in India, provided they get an import registration and certification.
Pfizer’s vaccine has received authorization from all the top regulators and is keen on supplying the vaccine to the government but is yet to apply for a clearance.
The third study also showed resistance to Eli Lilly’s monoclonal antibody bamlanivimab, but it was efficiently inhibited by Regeneron’s monoclonal antibody cocktail of casirivimab and imdevimab.
Last week, the Indian regulator had given Regeneron’s partner Roche an emergency licensure for the antibody cocktail, while the US FDA had last month rescinded its authorization to Eli Lilly monoclonal antibody due to the resistance of mutant strains against the drug.
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