The highly contagious delta variant of the coronavirus is rapidly spreading in Southeast Asia as concerns mount over the efficacy of China’s Sinovac Biotech vaccine, which has been used in several countries in the region.Questions over the effectiveness of Beijing’s vaccine have prompted some governments, including Thailand’s, to consider giving people vaccinated with the Sinovac CoronaVac a booster shot, this time from another vaccine manufacturer such as AstraZeneca.Sinovac is one of seven coronavirus vaccines that have received emergency use approval by the World Health Organization. Studies on the efficacy rate are ongoing, but Sinovac appears to be less powerful against the virus than other COVID-19 vaccines. In Indonesia, the majority of vaccine doses offered so far — nearly 90% — have been made by Sinovac.Concerns about Sinovac have made some Indonesians hesitant to receive the shot. One-third of residents in the province of Jakarta said they are still undecided about whether to be vaccinated, according to a .Overall, little peer-reviewed data on the Sinovac vaccine are available. What information is available suggests that the vaccine is less potent than other COVID-19 vaccines, though it still gives users significant protection.In June, the government of Uruguay released data showing Sinovac reduced COVID-19 infections by 61%, hospitalizations by 92% and deaths by 95%. The New England Journal of Medicine published a study in early July that used results from a mass vaccination campaign that began in February in Chile. The study results showed Sinovac reduced COVID-19 infections by 65.9%, is 87.5% effective at preventing hospitalizations and 86.3% effective at preventing deaths.In comparison, the WHO says the Pfizer vaccine is 95% effective at preventing symptomatic infection and the Moderna vaccine is 94% effective.Public Health England said last month its analysis of how well the vaccines work against the delta variant suggests the Pfizer shot is 96% effective against cases severe enough to require hospitalization, compared to 92% for the AstraZeneca vaccine. In Cambodia, Sinovac doses represent a much smaller proportion of the vaccination effort than in Indonesia, but are still a major part of the campaign that has given at least one dose of a vaccine to about 5 million people.Health Ministry Secretary of State Or Vandine told VOA Khmer that vaccines used in Cambodia’s mass vaccination drive – Sinovac, Sinopharm and AstraZeneca – were effective in preventing severe illness and death, but that fully vaccinated people still needed to observe COVID-19 measures, like mask wearing and social distancing. Chea Phenghour, 21, a third year student of civil engineering at Norton University in Phnom Penh, said he was vaccinated with two doses of Sinovac in early June, though he is unsure about the efficacy level. “I don’t know exactly the efficacy,” he said. “But I don’t strongly rely on vaccines. I have to be careful by myself. If we freely go out in the gathering, vaccines can’t help fight [the virus].” Sinovac vaccine doses have also been a big part of the COVID-19 vaccination efforts in the Philippines and Thailand, but both countries have also relied on a significant portion of doses from other manufacturers such as Pfizer and AstraZeneca.Indra Yoga, Sun Narin, Aun Chhengpor, Steve Baragona, Luke Hunt contributed to this report.Some information for this report came from the Associated Press and Reuters.
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