Bangkok: A research by Thai scientists shows that a cocktail of two doses of Sinovac coronavirus vaccine and one dose of AstraZeneca creates sufficient immunity in humans to resist the Delta strain, while just two doses of Sinovac are effective only against the Alpha strain and do not guarantee sufficient protection from Delta.
The study, an excerpt of which was shared by one of its authors, famous Thai virologist Thiravat Hemachudha, on his Facebook, involved volunteers from medical staff working with COVID-19 patients and regular people. It showed that two doses of Sinovac create sufficient immunity to the Alpha strain of the coronavirus, but cannot cope with the more viral Delta one.
At the same time, a cocktail of one dose of Sinovac and one dose of AstraZeneca increases the amount of antibodies more than two doses of Sinovac, with over 90% efficacy versus 80-90%, respectively. The sequential use of two doses of Sinovac and one dose of AstraZeneca brings efficacy up to 99%, significantly boosting immunity to both the Alpha and the Delta strains, Hemachudha said.
“The main result of the study is that it proves that the 2Sinovac + 1AstraZeneca formula provides sufficient immunity against the Delta strain. It can become a temporary solution for immunizing medical and front-line workers who constantly deal with patients and put their health at great risk,” the researcher stressed.
He added that due to a shortage of mRNA vaccines, which work better for the Delta strain, the combination of more readily available drugs — Sinovac and AstraZeneca — is a viable option.
On Friday, Thailand once again decided to toughen coronavirus-related restrictions, including a nighttime curfew starting July 12, as the daily number of COVID-19 cases has gradually approached 10,000. In a bid to curb the pandemic, the National Security Council proposed to extend the state of emergency until September 31. The current emergency is set to expire on July 31.