HONG KONG (BLOOMBERG) – There is a substantial gap in the amount of antibodies that mRNA and inactivated vaccines can generate against the virus that causes Covid-19, according to a Hong Kong study.
It is the latest finding on what may have contributed to the varied outcomes following mass vaccination using different types of shots.
The research, published in The Lancet on Thursday (July 15), found that antibody levels among Hong Kong health workers who have been fully vaccinated with BioNTech’s mRNA shot are about 10 times higher than those observed in the recipients of the inactivated vaccine from Sinovac Biotech.
While disease-fighting antibodies do not account for the full picture when it comes to measuring the ability to generate immunity and the effectiveness of Covid-19 vaccines, “the difference in concentrations of neutralising antibodies identified in our study could translate into substantial differences in vaccine effectiveness”, the researchers said.
The finding adds to a growing body of evidence suggesting the superiority of mRNA vaccines in providing potent and comprehensive protection against Sars-CoV-2 and its variants, compared with vaccines developed by more traditional methods such as inactivated shots.
Countries from Israel to the United States that have relied mostly on mRNA vaccines from Pfizer and its German partner BioNTech, as well as Moderna, have seen a marked reduction in infections.
Those using mostly inactivated shots from China’s Sinovac and Sinopharm have not experienced as much of a dent in case numbers, though the use of both kinds has significantly prevented more severe Covid-19 cases and fatalities.
The lower effectiveness of inactivated vaccines has prompted countries from Thailand to the United Arab Emirates to offer already fully vaccinated people another booster shot as the more infectious Delta variant fuels a resurgence in infections.
The Hong Kong study also suggested that future research could look into how booster shots could shore up antibody levels and protection among people vaccinated with inactivated shots.