Pfizer Inc and its German partner BioNTech SE have submitted to US regulators the initial data from an early-stage trial toward seeking authorization of a booster dose of their Covid-19 vaccine, the drugmakers said on Monday.
They said the third dose showed significantly higher neutralising antibodies against the initial SARS-CoV-2 virus compared to the two doses as well as against the Beta and the highly infectious Delta variants.
Pfizer has said its vaccine’s efficacy drops over time, citing a study that showed 84% effectiveness from a peak of 96% four months after a second dose. Some countries including Israel have already gone ahead with plans to give booster doses.
However, the decision by a few rich countries to buy booster shots has drawn the ire of health activists and the World Health Organisation (WHO), which has called for a moratorium on boosters until at least the end of September.
Pfizer and BioNTech had said that all patients in the trial received the third shot, BNT162b2, eight to nine months after their second dose.
The drugmakers will submit the trial data to the European Medicines Agency and other regulatory authorities in the coming weeks. They said results from a late-stage trial of the third dose are expected shortly.
Last week, U.S regulators authorized a third dose of COVID-19 vaccines by Pfizer-BioNTech and Moderna Inc for people with compromised immune systems who are likely to have weaker protection from the two-dose regimens.
