Dec 31, 2021
Pfizer backs two-dose vaccine schedule after U.K. shift
, Bloomberg News
Pfizer Inc. said the second dose of its COVID-19 vaccine should be delivered to individuals within the recommended 21-day period, calling into question a decision by the U.K. to space out the dosing regimen.
The U.K. decision not to hold back any of its vaccine supply is aimed at quickly reaching as many high-risk people as possible. Under the government plan, second doses could be administered as many as 12 weeks later, longer than the three-week timing determined as optimal by Pfizer’s late-stage studies and the four weeks suggested for the shot developed by Moderna Inc.
Pfizer said Thursday that people should get their shots on the recommended schedule, warning that “there is no data to demonstrate that protection after the first dose is sustained after 21 days.” The U.S. Food and Drug Administration also recommends that the second dose be taken at 21 days.
Anthony Fauci, the top U.S. infectious disease expert, told NBC’s Today Show on Thursday that spreading out the two doses is “under consideration,” though he didn’t specify by who.
“I still think, if done properly, you can do a single dose, reserve doses for the second dose, and still get the job done,” Fauci said. But he added “you can make an argument, and some people are, about stretching out the doses and giving a single dose across the board and hoping you’re going to get the second dose in time to give to individuals.”
In its statement, Pfizer said surveillance is needed on any alternative vaccination schedules, and that authorities should work to ensure each recipient is afforded the maximum possible protection.
“Data from the Phase 3 study demonstrated that, although partial protection from the vaccine appears to begin as early as 12 days after the first dose, two doses of the vaccine are required to provide the maximum protection against the disease, a vaccine efficacy of 95%,” Pfizer said in its statement.
An FDA document of frequently asked questions on Pfizer and partner BioNTech SE’s vaccine notes that the agency’s assessment of the safety and effectiveness of the vaccine was based on data on patients who received two shots three weeks apart.
