In a Hong Kong study, people who received BioNTech vaccine had 10 times more antibodies than those that got China’s Sinovac.
A team of researchers at Hong Kong University conducted a study comparing vaccine immunogenicity among 1442 healthcare workers. They compared the level of antibodies produced among the participants after receiving either the BioNTech vaccine or Sinovac. The healthcare workers belonged to various hospitals and clinics across Hong Kong. Researchers measured the antibody concentrations prior to vaccination, before the second dose, and 21-35 days after the second dose.
The Pfizer-BioNTech vaccine is an mRNA vaccine and has shown strong efficacy among real-world studies. Unlike other vaccines, it works by introducing mRNA containing viral spike proteins within the body. In response, the immune system recognizes the antigen and starts producing antibodies. This relevantly new vaccine technology has shown great success in controlling infections.
On the other hand, China’s Sinovac is an inactivated vaccine and has shown lower efficacies and greater breakthrough infections among vaccine recipients. Recently, 300 healthcare workers in Indonesia contracted COVID-19 despite being vaccinated with Sinovac. However, its easy storage requirements and lower cost make it a suitable vaccine for low-income countries.
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In the report published in the Lancet Microbe, researchers report preliminary data from 93 of the study participants. 63 of them received the BioNTech vaccine and the remaining 30 received Sinovac. Results showed that the BioNTech group had high antibodies after the first dose; with a further increase after the second dose. Whereas the Sinovac group demonstrated low levels of antibodies after the first dose and a moderate increase after the second dose. Thus, providing further evidence of the increased protection provided by mRNA vaccines as compared to traditional vaccines.
However, study author Ben Cowling believes that people should still go and get vaccinated with Sinovac. As an inactivated vaccine is still better than no vaccine. Moreover, the authors of the study point out the need for booster shots, especially among those receiving traditional vaccines like Sinovac. Earlier booster shots can likely provide increased protection to these people and help curb infections.
Comparative immunogenicity of mRNA and inactivated vaccines against COVID-19, Lancet Microbe, DOI: 10.1016/S2666-5247(21)00177-4