In a major policy change, the Public Health Ministry has decided to use the AstraZeneca vaccine for the second jab for those who received Sinovac as the first dose.
Public Health Minister Anutin Chanvirakul announced the change on Monday.
AstraZeneca would be administered as the second shot three or four weeks after the Sinovac inoculation. A combination of the two vaccines would provide a better defence against the Delta variant of the virus, he said.
Mr Anutin did not say what people who have had two doses of Sinovac should do when the change in policy comes into force, or how it would affect people awaiting their first or second dose of the Astra Zeneca vaccine.
The change was announced after a meeting of the National Communicable Disease Committee as part of measures to cope with Delta, the highly contagious variant of the virus first detected in India and rapidly becoming the dominant strain in Thailand
Another key measure announced was a booster shot drive starting this month for health workers on the front line who had received two doses. They would receive a dose of the AstraZeneca or Pfifer vaccine.
He said daily fatalities could exceed 100 and new cases rise above 10,000 a day if no adjustments were made to the current programme.
The committee did not approve allowing people to carry out Covid-19 testing at home, as had been widely expected. Rapid antigen test kits are still allowed for health professional use only.
There had been speculation that people would be allowed to self-test at home as testing units were unable to cater to demand after infections and fatalities soared in Bangkok and neighbouring provinces.