Bottles of the Sinovac vaccine are seen at a hospital, as Indonesia drives mass vaccination for the coronavirus disease (COVID-19), in Jakarta, Indonesia, January 21, 2021. REUTERS/Willy Kurniawan
Antibodies triggered by Sinovac Biotech's (SVA.O) COVID-19 vaccine decline below a key threshold from around six months after a second dose for most recipients, although a third shot could have a strong boosting effect, according to a lab study.
Chinese researchers reported the findings from a study of blood samples from healthy adults aged between 18-59 in a paper published on Sunday, which has not been peer-reviewed.
For participants receiving two doses, two or four weeks apart, only 16.9% and 35.2% respectively still had a level of neutralizing antibodies above the threshold six months after the second dose, the paper said.
Those readings was based on data from two cohorts involving more than 50 participants each, while the study gave third doses to a total of 540 participants.
When participants in some cohorts were given a third dose, about six months after the second, neutralizing antibody levels after a further 28 days had increased around 3-5 fold from the levels seen four weeks after the second dose, the study showed.
The study was conducted by researchers at disease control authorities in Jiangsu province, Sinovac, and other Chinese institutions.
Researchers cautioned the study did not test the antibodies' effect against more transmissible variants, and that further research was needed to assess antibody duration after a third shot.
Reporting by Roxanne Liu and Ryan Woo Editing by Mark Potter
Afghan Women Speaks on Unyielding Hope of Restoring Their Homeland
QF to Host Education-Focused Virtual Events at United Nations General Assembly and Global Goals Week
This Manpower Firm in Doha Guides You in Hiring Nurse for Your Hospital
Qatar SC wins HH the Amir’s Table Tennis Cup 2020-2021 season
Pfizer: Know all about the Covid-19 vaccine and its usage in Qatar
FIFA’22 over Covid-19: Qatar limbers up for the World Cup amidst a worldwide pandemic
Top 5 Art Galleries You Must Explore in Qatar
The Expert Outsourcing Service in Qatar That Guides You in Employing a Qualified Graphic Designer