BEIJING (Reuters) – Sinovac Biotech’s COVID-19 vaccine may not trigger sufficient antibody responses against a new variant identified in Brazil, a small-sample laboratory study showed.
The emergence of variants of the new coronavirus has raised concerns that vaccines and treatments developed based on previous strains may not work as robustly.
Plasma samples collected from eight people vaccinated with Sinovac’s CoronaVac have failed to effectively neutralize the P.1 strain, or 20J / 501Y.V3, the researchers said in an article published on Monday before the peer review.
“These results suggest that the P.1 virus may escape the neutralizing antibodies induced by … CoronaVac,” said researchers at the University of São Paulo in Brazil, the School of Medicine at the University of Washington in the United States and some other institutions in the paper.
CoronaVac is being used in mass vaccination campaigns in countries like China, Brazil, Indonesia and Turkey.
Although the study suggests that reinfection may occur in vaccinated individuals, the protection given by CoronaVac against severe COVID-19 may indicate other mechanisms in the human immune system, in addition to antibodies, may also contribute to reducing the severity of the disease, the researchers said.
A Sinovac spokesman was not immediately available for comment. Chief Executive Yin Weidong said in a program broadcast by state broadcaster CGTN on Thursday that the company is “fully capable” of using current research and manufacturing capabilities to develop a new variant vaccine, if necessary.
He also said that the process would take much less time than developing CoronaVac.
(Reporting by Roxanne Liu and Ryan Woo; Editing by Raju Gopalakrishnan)