FDA chief Rolando Enrique Domingo told Reuters the Gamaleya Institute’s request to widen the time interval between two vaccine doses to 90 days from 21 would have to be “reevaluated” as the Russian vaccine maker submitted more data to support it.

“Our vaccine experts recommended a maximum dose interval of 42 days. No problem in delaying the second dose, but if we give it within 42 days we have reason to believe that the results are going to be very good,” Domingo told a separate briefing.

In making the request, Gamaleya “submitted studies showing immunogenicity beyond the 21-day interval”, Domingo said.

The Southeast Asian country is due to receive 170,000 doses of Sputnik V today, taking initial supplies to 235,000 shots of the vaccine.

The Philippines has so far granted emergency use authorisation to eight Covid-19 vaccine brands, with the Pfizer-BioNTech shot the only one allowed so far to be given to children as young as 12.

Domingo said China’s Sinovac Biotech requested yesterday the FDA have its authorisation amended to include children aged three to 17.

The Philippines has so far given 9.05 million people a first dose of a vaccine and 2.92 million a second dose, still a long way from its goal of fully immunising 70 million of its 110 million people this year.

The number of daily coronavirus infections in the Philippines, which is battling one of the worst outbreaks in Asia, totalled 1.44 million as of July 6, while the number of deaths has reached more than 25,000.