The move is the first publicly announced mix-and-match of a Chinese vaccine and a Western-developed shot, as a new preliminary Thai study raised doubts about the long-term protection of the Sinovac vaccine.
There have been no studies specifically on mixing Sinovac and AstraZeneca released, but a growing number of nations are looking at mix-and-match of different vaccines or giving a third booster dose amid concerns new and more contagious variants may escape approved vaccines.
The announcement came after Thailand’s health ministry said 618 medical workers out of 677,348 personnel who got two Sinovac doses became infected from April to July with one nurse succumbing to the disease.
Indonesia has also reported breakthrough infections among medical workers who are fully inoculated with the Sinovac vaccine.
Based on a preliminary Thai study of 700 medical staff, the Sinovac was found to protect a patient for the first 60 days at an efficacy rate ranging between 60% -70% with the second jab and would decrease to half the efficacy rate after 40 days.
World Health organization is still wary of this new idea owing to the fact that there is no sufficient data to help determine whether it will work or not.
“It’s a little bit of a dangerous trend here. We are in a data-free, evidence-free zone,” WHO Chief Scientist Soumya Swaminathan said in the online COVID-19 briefing. She said studies on the topic are currently being carried out.