A new study from Pfizer and BioNTech shows that a booster shot of their COVID-19 vaccine strongly extends protection and increases the human antibody response against the coronavirus.
The companies said that they have demonstrated that a third dose of their vaccine, given six months after the second, increases neutralizing antibodies five to tenfold against the original virus. Protection against severe disease remained strong six months after vaccination, but effectiveness against symptomatic disease began to decline toward the end of that period, the companies said.
“That, plus the arrival of new variants, are key factors driving our belief that a booster dose will likely be necessary to maintain the highest levels of protection.” They also added that and they are developing a vaccine targeted directly at the Delta variant, which first arose in India. The highly contagious delta variant is said to be responsible for the disastrous second wave and high case-load of India. It also accounts for over half the COVID-19 cases in the United States, according to the CDC.
The companies also said that they are updating their vaccine, called BNT162b2, to directly address the Delta variant. They added that the production of materials for a clinical trial is going on, which they expect to begin in August, pending regulatory approvals. Neither the companies nor the government recommended booster shots yet until their safety and effectiveness can be fully explored. In a joint statement late Thursday, the FDA and the Centers for Disease Control and Prevention emphasized that people who have been fully vaccinated do not need booster shots yet.
A US Government statement said that FDA, CDC, and NIH are engaged in a science-based, rigorous process to consider whether or when a booster might be necessary. “This process takes into account laboratory data, clinical trial data, and cohort data – which can include data from specific pharmaceutical companies, but does not rely on those data exclusively … We are prepared for booster doses if and when science demonstrates that they are needed.”