Pfizer and BioNTech announced on July 8, 2021 that they would seek regulatory authorization for a third booster dose of their Covid-19 vaccine.
The announcement comes after the initial data from an ongoing trial showed that a third shot increases the antibody level by 5-10 times against the original SARS-CoV-2 strain and the Beta variant first detected in South Africa, in comparison to the first two doses alone.
The two companies are expected to publish more definitive data soon in a peer-reviewed journal and also submit it to the US Food and Drug Administration (FDA), European Medicines Agency (EMA) and other regulatory authorities in the coming weeks.
Why is there a need for a third vaccine shot?
• Pfizer and BioNTech believe that a third dose of the vaccine may be needed within six to 12 months after full vaccination. This is based on the efficacy drop that was seen in Israel after six months.
• The statement from the two companies noted that while protection against severe disease remained high across the full 6 months, a decline in efficacy against symptomatic disease over time and the continued emergence of variants are expected.
• The US FDA along with the US Centers for Disease Control and Prevention (CDC) released a joint statement on July 8, 2021 informing that the authorities were studying whether or when a booster might be necessary.
• The two agencies noted that the fully vaccinated Americans do not need a booster shot at this time but they are prepared for booster doses if and when the science demonstrates that they are needed.
Third shot more effective against Delta variant?
Pfizer and BioNTech are aiming to seek authorisation for a third booster shot amid the global spread of highly transmissible Delta strain of COVID-19, which was first detected in India and was responsible for the deadly second wave of COVID-19 in the country in April-May 2021. The companies are expecting the third booster shot to perform well against the variant as well.
Pfizer and BioNTech are developing a Delta-specific vaccine as well as a cautionary measure, the first batch of which has been manufactured at BioNTech’s facility in Mainz, Germany.
The clinical studies of the vaccine are expected to begin in August, subject to regulatory approvals.