Sri Lanka is administering Pfizer shots to people who were left waiting after receiving their first AstraZeneca doses earlier this year.
Mixing two vaccines is still being studied for its effectiveness, but Sri Lanka health officials approved it due to a severe AstraZeneca shortage.
Sri Lanka received 26,000 doses of Pfizer on Monday as the first batch of 5 million shots to be received this year. It started rolling them out Wednesday to residents 55 and older in the capital Colombo.
About 384,000 people were fully vaccinated before Sri Lanka ran out of AstraZeneca doses with 540,000 people only partially vaccinated.
Channa Jayasumana, the state minister overseeing pharmaceuticals, said getting Pfizer as the 2nd dose was optional and a consignment of AstraZeneca vaccine was expected this month.
Sri Lanka also has used Sinopharm and the Russian Sputnik V to vaccinate people against COVID-19.
Sri Lanka has seen a sharp increase of coronavirus infections and deaths since April. It has recorded 266,499 cases with 3,268 fatalities overall.
