Researchers have urged governments to delay administering the second dose of Pfizer Covid-19 vaccine, which they said had an efficacy of 92.6% after the first dose.
The researchers, Danuta Skowronski and Gaston De Serres ,said their findings were derived from Pfizer's documents submitted to the US Food and Drug Administration.
These findings were also similar to the first-dose efficacy of 92.1% reported for Moderna mRNA-1273 vaccine, they said in their letter published in the New England Journal of Medicine.
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