The remaining 263,250 doses are expected to reach Hanoi’s Noi Bai airport Friday morning, a representative of the Department of International Cooperation of the Health Ministry told VnExpress.
The vaccine was handed over to Vietnam following an announcement of U.S. Vice President Kamala Harris on Wednesday.
Harris, who is paying an official visit to Vietnam from Aug. 24-26, said the vaccine "will start arriving within the next 24 hours" at her meeting with Vietnam’s Prime Minister Pham Minh Chinh in Hanoi.
The batch raises the total U.S. donation to Vietnam to six million doses after five million Moderna doses were handed over via Covax.
Pfizer is the first Covid-19 vaccine that has been fully licensed by the U.S. Food and Drug Administration.
Its developer, U.S.-based firm Pfizer and Germany's BioNTech Inc, said in April the vaccine is 91 percent effective against Covid-19, dropping from the 95 percent they announced last December.
In Vietnam, the Pfizer vaccine was approved for emergency use on June 12.
Vietnam has signed contracts to buy 51 million doses of this vaccine within this year, including 20 million doses for those aged 12 to 18.
Pfizer is now the only vaccine Vietnam allows for mixed administration.
As greenlighted by the Health Ministry, people receiving the AstraZeneca vaccine first could get the Pfizer shot the second time around in case of supply shortages and with prior agreement.
Vietnam has so far received more than 24 million Covid-19 vaccine doses of different types, via Covax, government support, and commercial contracts.
The country of 96 million has administered more than 18 million doses, with more than two million people having received two shots.