Combining Sinovac and AstraZeneca vaccines has shown high efficacy in dealing with the Delta variant of the coronavirus, according to the Department of Medical Sciences.
Department chief, Dr Supakit Sirilak, said yesterday that a Sinovac and AstraZeneca mix was the best combination under current circumstances to speed up immunity.
He cited lab test results from a study conducted in association with Siriraj Hospital.
Dr Supakit said blood samples from 125 participants, aged 18-60 years, who received a Sinovac shot and then an AstraZeneca jab, showed the quantitative level of body immunity was an average of 716, compared with 117 among those who receive a full course of Sinovac and 207 for two AstraZeneca shots.
"The laboratory tests prove that mixing Sinovac and AstraZeneca is correct. However, the test has not yet answered our question on efficacy duration, so further study is needed to determine when we should get the booster dose," he said.
He insisted that a higher level of antibody was found with mixing vaccines as was suggested by the national communicable disease board, but less time was spent creating the antibody.
People will get the second dose of AstraZeneca three weeks after getting the first Sinovac shot. The immunity level will be up just two weeks after getting both doses.
Usually, the Ministry of Public Health advises around 8-12 weeks before getting the second shot of AstraZeneca.
"The side-effects associated with the combined vaccine are nothing to worry about, as they are no different from getting the AstraZeneca vaccine," he said.
He also said the department will collect information on people receiving the Pfizer vaccine for further study, the results of which should be available in about a month. At least 300,000 people have received the mRNA-based Pfizer vaccine.
The department has plans to conduct a study of antibody levels when the vaccine is given under the skin, instead of into muscle as done at present.
It says that if a small amount of vaccine can be used under the skin, then four to five times less vaccine could be administrated to more people.
If the results are the same, it can also see a big change in vaccine management.