Researchers call for second Pfizer vaccine dose to be delayed

A pair of researchers in a letter published by the New England Journal of Medicine on Wednesday argued that the second dose of the Pfizer-BioNTech coronavirus vaccine could be delayed, despite previous opposition to such a move from health authorities. 

In the letter, Canada-based researchers Danuta Skowronski and Gaston De Serres argued that based on analysis of documents submitted by Pfizer to the Food and Drug Administration (FDA), the vaccine has an approximately 92.6 percent efficacy rate following the first dose. 

Pfizer’s vaccine, which is currently authorized to be issued in two doses 21 days apart, reported a 94.8 percent effectiveness against COVID-19 following two doses.

Given the relatively small increase in the efficacy rate between the first and the second dose, the authors argued in the letter that “the benefits derived from a scarce supply of vaccine could be maximized by deferring second doses until all priority group members are offered at least one dose.” 

The authors acknowledged that while there “may be uncertainty about the duration of protection with a single dose,” the second dose weeks after the first “provides little added benefit in the short term, while high-risk persons who could have received a first dose with that vaccine supply are left completely unprotected.” 

The researchers further argued that “postponement of the second dose is a matter of national security that, if ignored, will certainly result in thousands of Covid-19–related hospitalizations and deaths this winter in the United States — hospitalizations and deaths that would have been prevented with a first dose of vaccine.”

The medical journal also published Pfizer’s response to the letter, in which the pharmaceutical manufacturer noted that “alternative dosing regimens” for its vaccine have not yet been properly evaluated. 

“The decision to implement alternative dosing regimens resides with health authorities,” Pfizer continued. “However, we at Pfizer believe that it is critical for health authorities to conduct surveillance on implemented alternative dosing schedules to ensure that vaccines provide the maximum possible protection.”

The letters come as experts remain split on whether to delay the second doses of coronavirus vaccines in order to allow more people in high-priority groups to more quickly receive protection against COVID-19. 

Anthony Fauci, the nation’s top infectious diseases expert, said on NBC’s “Meet the Press” on Sunday that he disagreed with experts calling for a delayed second dose, adding that more research would be needed to measure the long-term level of protection individuals could receive with just one dose. 

“The amount of time that it will take, the amount of people you would have to put into the study — by that time, we will already be in the arena of having enough, of having enough vaccines to go around anyway,” Fauci said. 

“But what we have right now, and what we must go with, is the scientific data that we’ve accumulated, and it’s really very solid,” he added. “We know that with each of these it’s either 21 days or 28 days. You can do both. You can get as many people in their first dose at the same time as adhering, within reason, to the timetable of the second dose.”