Antibodies developed by Sinovac Biotech’s Covid-19 vaccine start weakening in most recipients around after six months of receiving the second dose, although a third shot could have a strong boosting effect, the latest lab study suggests.
The study conducted by Chinese researchers and published on Sunday is based on blood samples taken from healthy adults aged between 18-59. The findings have not been peer-reviewed.
It found that people receiving two doses, with the gap of two or four weeks, only 16.9 per cent and 35.2pc, respectively, still had antibodies above the threshold six months after receiving the second dose.
The readings were based on data from two groups comprising more than 50 participants each, while the third dose was administered to a total of 540 participants.
The study shows that the level of antibodies in participants, who were giving the booster shot, increased 3 to 5 fold after 28 days.
The study was carried out 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, Dawn reported.
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