Thailand to mix AZ and Sinovac doses, Health News, ET HealthWorld

Bangkok: Thailand will use the AstraZeneca vaccine as a second dose for those who received the Sinovac vaccine as the first dose in an attempt to increase protection, he said on Monday. The move is the first publicly announced mix-and-match of a Chinese vaccine and a vaccine developed in the West, as a new preliminary Thai study has raised doubts about the long-term protection of the Sinovac vaccine. “This is to improve protection against the Delta variant,” said Health Minister Anutin Charnvirakul, adding that the second dose of AstraZeneca would come three or four weeks after the first injection of Sinovac.

No specific study on mixing Sinovac and AstraZeneca has been published, but a growing number of countries are considering combining different vaccines or giving a third booster dose, as newer, more contagious variants may escape approved vaccines. The announcement came a day after Thailand’s health ministry said 618 medical workers out of 677,348 staff who received two doses of Sinovac were infected from April to July. A nurse died. Indonesia has also reported cases of infections among medical workers who are completely inoculated with the Sinovac vaccine.

On Monday, a preliminary Thai study of 700 medical staff found that Sinovac’s rate of protection ranged from 60% to 70% for the first 60 days after the second dose, but the rate steadily declined over time and appeared to be halve every 40 days.

WHO chief scientist Soumya Swaminathan on Monday advised against mixing and matching vaccines, calling it a “dangerous trend.” “We are in an area with no data and no evidence when it comes to mix and match,” she said. Reuters