Inoculation with two doses of China’s Sinovac vaccine can boost the neutralizing antibody level to 80-90% and provide immunity to the Alpha variant of the COVID-19 virus to some extent, but cannot fend off the highly contagious Delta variant, which is becoming dominant in Thailand and many other parts of the world, said a prominent Thai doctor today (Friday).
Two doses of the UK’s Oxford-AstraZeneca vaccine can, however, immunize people, with neutralizing antibody levels of over 90%, against the virulent Delta variant, according to Head of the Thai Red Cross Emerging Infectious Diseases Health Science Centre, Professor Dr. Thiravat Hemachudha, who conducted a joint study with Dr. Anan Jongkaewwattana, a virologist at BIOTEC, and Dr. Khate Sripratak of the Central Chest Institute of Thailand.
The study reveals that two doses of Sinovac, plus a booster dose of AstraZeneca, can prevent the Delta infection better than two doses of Sinovac, but still less than two doses of AstraZeneca, the doctor said.
Although there are no mRNA vaccines available in Thailand yet, for frontline medical personnel, who are mostly inoculated with Sinovac, getting a booster dose of AstraZeneca will be enough to protect them from contracting the Delta variant, ahead of the availability of mRNA vaccines, he added.
Thailand has received 14.5 million doses of Sinovac vaccine and two million doses of Sinopharm, also from China.
