(Reuters) – The second dose of COfID-19 Pfizer Inc. vaccine could be postponed to cover all priority groups because the former is extremely protective, two Canadian researchers said in a letter published in the New England Journal of Medicine .
The vaccine was 92.6% effective after the first dose, said Danuta Skowronski and Gaston De Serres, based on an analysis of documents submitted by the drug doctor to the US Food and Drug Administration (FDA).
These findings were similar to the effectiveness of the first dose of 92.1% reported for Moderna Inc.’s mRNA-1273 vaccine, according to the letter here on Wednesday.
In its response, Pfizer said that alternative vaccine dosing regimens have not yet been evaluated and that the decision rests with the health authorities.
Some low-resource countries are analyzing dosage patterns or volumes that differ from how vaccines have been tested in clinical trials.
There are differences in the merits of such strategies, with some arguing that the urgency of the pandemic requires flexibility, while others oppose abandoning data-driven approaches for reasons of opportunity.
Skowronski and De Serres warned that there may be uncertainty about the duration of single-dose protection, but said the administration of the second dose one month after the first provided “small added benefits in the short term”.
Skowronski works at the Centers for Disease Control in British Columbia, while De Serres is at the National Institute of Public Health in Quebec
In the UK, authorities said the data supported his decision to switch to a 12-week dosing schedule for COVID Pfizer. Both Pfizer and partner BioNTech have warned that they have no evidence to prove it.
The Pfizer vaccine is authorized for 21 days.
The US FDA and the European Medicines Agency adhered to the range tested in the studies.
Reporting by Shubham Kalia and Ann Maria Shibu in Bengaluru; Editing by Vinay Dwivedi and Sriraj Kalluvila