China administers 1.8 billion Covid vaccines as Sinovac says third shot delivers big increase in immunity

The Chinese authorities have hit a new milestone, administering 1.8 billion vaccines in the fight against Covid-19, as shot-maker Sinovac says efficacy concerns can be overcome using a third jab.

On Wednesday, China’s National Health Commission said that a total of 1.808 billion vaccines had been administered in the country, after 13 million doses were given on Tuesday.

Although a breakdown of first and second shots is not available, the number of jabs administered is roughly enough to cover around 65% of the country’s 1.4 billion people.

The milestone comes as Chinese vaccine-makers Sinovac said that a third dose of their CoronaVac shot substantially increased antibody levels during trials. 

The study, which was published on Sunday in medRvix, stated that patients who received a 3 microgram third dose saw a seven-fold increase in antibody levels compared to the levels recorded 28 days after the second dose.

The scientists noted that antibody levels “declined substantially” six months after two doses, suggesting a third shot may be necessary.

In a statement sent to the Global Times on Monday, Sinovac said the study will provide important information to policymakers concerning plans for booster shots.

The vaccine’s efficacy has been questioned in recent months after several studies and real-world data suggested its performance wasn’t matching up with clinical trial data. A Thai study suggested that vaccine-induced antibodies halved every 40 days after the second dose.

China’s medical regulator has approved a trial to combine the Sinovac shot with a DNA vaccine developed by American biotech company Inovio, the company’s boss said on Tuesday. The trial is due to begin in the autumn.

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