Pfizer is looking to fast-track approval for a third booster dose of its covid-19 vaccine and will request emergency authorization from the U.S. Food and Drug Administration in August, Pfizer research head Mikael Dolsten said in a Thursday interview with Bloomberg.
Initial data from human studies has been promising, he said, showing that a third dose is not only safe but can greatly increase immune protection against the virus. Results indicate that a third dose can raise neutralising antibody levels by five to tenfold compared with the original vaccine. Once Pfizer has compiled more data, it plans to ask the FDA to authorise a booster shot that could be administered to patients six to eight months after they received their original two doses. The company, which produces the vaccine in partnership with BioNTech, is also in talks with regulators in the European Union and other countries about its results so far.
Pfizer’s results are based on an initial cohort of roughly 10 to 20 people who received the booster, and “the data set is so clear we have complete confidence that the full study will reproduce this,” according to Dolsten.
“There is a lot of fear and concern” about variants, he told the outlet. “We are confident that such a boost will be highly effective against the Delta variant.”
With new strains of the virus spreading quickly, including the ultra-transmissible Delta variant, it’s led to increasing concerns about the efficacy of existing covid-19 vaccines and how they will hold up against these and future mutations. Israel health officials recently released new data indicating that, among the fully vaccinated, the Pfizer vaccine is about 64% effective at preventing any infection from Delta and 94% effective at preventing serious illness from the variant, though these results have yet to be vetted by outside scientists.
In his interview with Bloomberg, Dolsten said Pfizer interprets Israel’s findings as a sign that the population’s blood-antibody levels have fallen since officials started rolling out vaccines at the beginning of the year. This underlines the importance of administering booster shots to patients who can be particularly vulnerable to the virus, including the elderly and those with compromised immune systems.
“When you have low blood levels of an antibody, viruses that are highly contagious may reinfect and cause mild disease,” he said.
He added that Pfizer plans to start human trials of a new booster specifically designed to fight the Delta variant, though it’s unlikely this customised vaccine will be needed given how well its existing vaccine works against this new strain.
Pfizer is aiming to produce 3 billion doses of its vaccine this year and 4 billion doses next year. Previously, the company’s CEO, Albert Bourla, speculated that people will likely need a booster dose of Pfizer’s vaccine every year, similar to an annual flu shot, but experts are still out on whether such shots will eventually be needed.