Pfizer and BioNTech announced that they have submitted Phase 1 data to the United States Food and Drug Administration (FDA) to support the evaluation of a third, or booster dose of the companies' COVID-19 vaccine for future licensure.

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In a statement on August 16, Pfizer said that the data also will be submitted to the European Medicines Agency (EMA) and other regulatory authorities in the coming weeks. "Vaccination is our most effective means of preventing COVID-19 infection - especially severe disease and hospitalisation - and its profound impact on protecting lives is indisputable. Still, with the continuing threat of the Delta variant and possible emergence of other variants in the future, we must remain vigilant against this highly contagious virus," Albert Bourla, Chairman and Chief Executive Officer, Pfizer said in the statement.

"The data we've seen to date suggests the third dose of our vaccine elicits antibody levels that significantly exceed those seen after the two-dose primary schedule. We are pleased to submit these data to the FDA as we continue working together to address the evolving challenges of this pandemic," he added. Ugur Sahin, MD, CEO and Co-founder of BioNTech said: "We continuously strive to stay at least one step ahead of the virus. This is why we aim to expand access to our vaccine for people around the world and are working on various approaches as part of our comprehensive strategy to address the virus and its variants today as well as in the future."

"This initial data indicate that we may preserve and even exceed the high levels of protection against the wild-type virus and relevant variants using the third dose of our vaccine. A booster vaccine could help reduce infection and disease rates in people who have previously been vaccinated and better control the spread of virus variants during the coming season," he added. The statement further said that Pfizer and BioNTech have submitted Phase 1 data - part of their Phase 1/2/3 clinical trial program - evaluating the safety, tolerability, and immunogenicity of a third dose of the COVID-19 vaccine in US adult participants from the Phase 1 trial of the two-dose series.

Participants received a 30-ug booster dose of BNT162b2 8 to 9 months after receiving the second dose. Results from this participant group show that the third dose elicited significantly higher neutralising antibodies against the initial SARS-CoV-2 virus (wild-type) compared to the levels observed after the two-dose primary series, as well as against the Beta variant and the highly infectious Delta variant.

Phase 3 results evaluating the third dose are expected shortly and will be submitted to the FDA, the EMA and other regulatory authorities worldwide. In the US, Pfizer and BioNTech plan to seek licensure of the third dose via a supplemental Biologics License Application (BLA) in individuals 16 years of age and older, pending FDA approval of the primary BLA submitted in May 2021.

A third dose of the Pfizer-BioNTech vaccine is not currently authorised for broad use in the US. However, under the current amended Emergency Use Authorisation, it has been authorised on August 12 for administration to individuals at least 12 years of age who have undergone solid organ transplantation, or who are diagnosed with conditions that are considered to have an equivalent level of immunocompromised. This authorisation is based on information from an independent report evaluating safety and effectiveness of a third dose in people who received solid organ transplants, the statement read.