Two researchers on Wednesday urged governments to delay administering the second dose of Pfizer Inc’s COVID-19 vaccine, which they said had an efficacy of 92.6% after the first dose, and that it was not significantly beneficial in the short term.
Danuta Skowronski and Gaston De Serres, said their findings were derived from Pfizer’s documents submitted to the US Food and Drug Administration.
According to a letter published in the New England Journal of Medicine, Skowronski and De Serres said these findings were also similar to the first-dose efficacy of 92.1% reported for Moderna Inc’s mRNA-1273 vaccine,
They cautioned that there may be uncertainty about the duration of protection with a single dose, but said that the administration of the second dose a month after the first provided “little added benefit in the short term”.
“Given the current vaccine shortage, 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,” the authors warned.
In its response, Pfizer said that alternative dosing regimens of its vaccine is yet to be evaluated and that the decision to do that resides with the health authorities.
“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,” it added.