Pfizer has pitched for a booster shot of its vaccine saying that the efficacy of its two-shot regimen declines after six months, even as the delta variant of the Covid-19 virus, which is much more contagious and transmissible, has spread to over 100 countries.
Pfizer and its German partner BioNTech said that work is in progress to develop a version of their Covid-19 vaccine that specifically targets the delta variant and clinical trials are expected to commence in August.
The vaccine maker duo said the studies conducted on people who took the third jab of the original vaccine have shown encouraging results. The companies said that a booster dose, given at an interval of six months from the second dose, leads to a five-to-ten-fold increase in the potency of antibodies produced against the original strain of the virus and its beta variant.
US central agencies CDC and FDA have reprimanded Pfizer for its push for a third dose stating that things are yet to be determined and the process will be followed in accordance with science. As of now, there is no need for a booster shot, they added.
A clash ensued between the drugmakers and the US government on July 8 when Pfizer-BioNTech said that they plan to seek the approval of the US FDA for the booster shot, and further projected that people would require an additional third shot after 6-12 months after the first two on the count of erosion of the overall effectiveness of the vaccine. The companies also said that data substantiating their claims of a booster dose leading to a surge in antibody levels would be submitted to regulators in the coming weeks.
In response to this, the US govt said that CDC and FDA’s “science-based, rigorous process” would determine the necessity of the aforementioned booster shots. “We are prepared for booster doses if and when the science demonstrates that they are needed,” said the agencies.