Hong Kong Study Reveals Pfizer's COVID-19 Vaccine Produces 10 Times More Antibodies Than Sinovac

Pfizer vaccine injection in France. (Wikimedia Commons/Claude TRUONG-NGOC)

JAKARTA - There is a substantial gap in the number of antibodies that mRNA vaccines can produce compared to inactivated vaccines against the virus that causes COVID-19, according to a study in Hong Kong.

These are the latest findings on what may have contributed to the mixed results, following mass COVID-19 vaccinations in different parts of the world using different types of vaccine injections.

The study, published in the medical journal 'The Lancet' on Thursday, July 15 found that antibody levels among Hong Kong health workers who had been fully vaccinated with Pfizer-BioNTech mRNA injections were about 10 times higher than those observed in inactivated vaccine recipients from Sinovac Biotech.

While disease-fighting antibodies do not shed light on the complete picture in measuring the immunity-generating ability and effectiveness of COVID-19 vaccines, "the differences in neutralizing antibody concentrations identified in our study could translate into substantial differences in vaccine effectiveness", the researchers said. Friday, July 16.

Pfizer vaccine illustration. (Wikimedia Commons/Prefeiture Campinas)

These findings add to the growing body of evidence demonstrating the superiority of mRNA vaccines, in providing robust and comprehensive protection against Sars-CoV-2 and its variants, compared to vaccines developed by more traditional methods such as inactivated injections.

Countries such as Israel to the United States, which mostly rely on mRNA vaccines from Pfizer and its German partner BioNTech, as well as Moderna, saw significant declines in COVID-19 infection cases.

Meanwhile, countries that use mostly inactivated vaccines from China's Sinovac and Sinopharm, have not seen much of a decline in the number of cases, although the use of both types has significantly prevented more severe cases and deaths of COVID-19.

The lower effectiveness of the inactivated vaccine has prompted countries from Thailand to the United Arab Emirates to offer another booster shot to people who are already fully vaccinated as the more contagious Delta variant is fueling a resurgence of infections.

To note, the Hong Kong study also suggests future research could look at how booster injections can sustain antibody levels and protection among people vaccinated with the inactivated injection.