Study reveals Sinovac’s CoronaVac vaccine leads to a significantly higher risk of severe COVID-19 symptoms than Pfizer-BioNTech’s vaccine
A recent study in Singapore has revealed that individuals vaccinated with Sinovac’s CoronaVac are nearly five times more likely to develop severe symptoms of COVID-19 compared to those who received the Pfizer-BioNTech vaccine. The study, published on April 12, involved 2.7 million individuals aged 20 and above who were vaccinated as part of the country’s national vaccination programme.
The research, which covered a seven-week period between October and November 2021 when COVID-19 cases surged due to the Delta variant, compared the effectiveness of the two inactivated whole virus vaccines—Sinovac and Sinopharm—with mRNA vaccines such as Pfizer-BioNTech and Moderna. The results showed a notable difference in effectiveness, with Sinovac vaccine recipients being 4.59 times more likely to experience severe illness, including hospitalization, ICU admission, or death, compared to those vaccinated with Pfizer-BioNTech. They were also 2.37 times more likely to contract the virus.
The study further indicated that Moderna’s vaccine provided stronger protection against severe disease than the Pfizer-BioNTech vaccine. Moderna recipients were found to be less than half as likely (0.42 times) to experience severe symptoms and were also less likely to be infected.
While the study acknowledges some limitations, such as potential biases due to comorbidities and vaccine choice, it stresses that both mRNA vaccines and inactivated vaccines offer sufficient protection against severe COVID-19. However, vaccination continues to be a crucial strategy in combating the pandemic.
As of the study’s publication, approximately 96% of Singapore’s eligible population had been vaccinated, with 73% having received their booster shots.
