Sinovac not effective against Delta variant, AstraZeneca is

A new study released today seems to have confirmed what many have feared: the Sinovac vaccine has little effectiveness in stopping the Covid-19 Delta variant. The Delta strain, first identified in India, is particularly dangerous as it has found to be much more contagious and is spreading rapidly throughout Thailand. It has been predicted that the variant will be the dominant form of Covid-19 in Thailand by next month.

Studies have shown that the Chinese-made vaccine is over 90% effective in producing neutralising antibodies to fight Covid-19, and with those antibodies, it provides 80-90% immunity for the Alpha variant of Covid-19. But data has shown the Sinovac vaccine is far less effective against the Delta variant in a joint study between the head of the Thai Red Cross Emerging Infectious Diseases Health Science Centre and a virologist at BIOTEC.

The study revealed that mRNA vaccines are the most effective in battling the Delta variant of Covid-19. Still, due to slowness in approving and ordering, no vaccine that works using the mRNA vaccine will be available in Thailand until at least October. Moderna and Pfizer all use mRNA technology and have now been approved in Thailand but have proved difficult to get inside the borders.

The Lawyers Association of Thailand recently berated the Thai government, saying that they have abandoned their constitutional duty to provide effective healthcare by failing to procure these mRNA vaccine brands and instead ordering nearly 11 million more Sinovac vaccines even though they are ineffective against the Delta variant. This new study released today seems to reinforce their position.

Without mRNA vaccines, the study revealed the next best protection is 2 doses of the AstraZeneca vaccine, which has been proven in the study to have over 90% neutralising antibody levels to combat the Delta variant. Thailand made a deal to produce AstraZeneca domestically, but the production facilities at Siam Bioscience has been plagued with delays and output shortfalls, halving the number of vaccines Thailand expected.

Another relatively quick fix, especially for those already fully vaccinated with the increasingly ineffective Sinovac vaccine, is an AstraZeneca booster shot. The study showed that just one injection of AstraZeneca in someone who already received Sinovac vaccines significantly increases the body’s ability to prevent Delta variant Covid-19 infections.

It’s not as effective as full AstraZeneca vaccination, but they are recommending a booster shot for frontline medical personnel right away to keep them safer from the Delta variant than only Sinovac vaccination will. Meanwhile, Thailand continues to import Sinovac vaccines, with 10.9 million recently ordered to add to the 14.5 million already received.

[Correction: Johnson & Johnson was previously misstated to be an mRNA vaccine.]

SOURCE: Thai PBS World