The move, announced on Monday by Public Health Minister Anutin Chanvirakul, comes after more than 600 medics were infected with Covid-19 despite having had both doses of Sinovac.
The new strategy was approved by the National Communicable Disease Committee as a measure to combat the fast-spreading Delta variant which is becoming dominant in Thailand. It will be rolled out first
Under the strategy, a Sinovac jab will be administered first, followed by an AstraZeneca jab 3-4 weeks later. AstraZeneca is thought to offer more protection than Sinovac against the Delta strain.
Front-line health workers, most of whom have had two Sinovac jabs, will also get the AstraZeneca booster 3-4 weeks after their second Sinovac shot. Most doctors can now get the booster since more than four weeks have passed since their second dose.
Data indicates that mixing-and-matching vaccine doses boosts protection against Covid-19.
The Department of Disease Control reported on Sunday that 618 medical professionals had been infected by the virus since April despite having had their second Sinovac jab.