Q&A on booster shots and COVID-19 variants | Updated: 2021-09-08 16:59

The National Health Commission has responded to key public concerns about COVID-19 booster shots and vaccine effectiveness amid a global resurgence of novel coronavirus and its variants in recent weeks.

A medical worker injects a COVID-19 vaccine at a temporary vaccination site in Beijing on Jan 2, 2021. [Photo/Xinhua]

1. Do I need to get a COVID-19 booster shot?

COVID-19 booster shots are currently recommended for three groups of people who have completed vaccination.

Those at higher risk of contracting the virus, such as port, customs, aviation and health workers, those over 60 years old and individuals with weak immune systems, and people planning to travel to high-risk areas, can choose to receive a booster using the same vaccine as their original inoculation six months after a full vaccine regimen.

However, there isn't enough evidence at present to support delivering COVID-19 booster shots to every member of the general public who have been fully vaccinated within six months, and further studies are needed.

2. What's the evidence for a booster shot's protective effect?

Sinopharm and Sinovac Biotech, the two major domestic vaccine developers, have conducted clinical studies on booster shots and presented the data on the safety and immunogenicity of an extra dose to health experts.

First and foremost, the data show it is safe to receive a booster shot six months after full immunization.

After two weeks, neutralizing antibodies in vaccinated individuals inoculated with a booster shot will be 10 to 30 times higher than before.

After six months, antibody levels will gradually go down. But the minimally retained antibody levels in individuals inoculated with a booster shot are still higher than the peak levels in those without.

From an immunogenicity perspective, vaccine-induced protection is considered to be improved by booster shots.

3. Can I use a different type of vaccine from the original inoculations for booster shots?

During China's current mass immunization campaign, different types of vaccines cannot replace each other. The same applies to booster shots until enough data on the safety and immunogenicity or effectiveness of such a strategy are obtained.

4. Can current COVID-19 vaccines tackle variants?

Yes. Since the mutation of the novel coronavirus has been relatively stable so far and not altered the structure of the virus in a fundamental way, current vaccines are still effective against variants of the virus, including the Delta variant.

5. How is China's research on the variants progressing?

China has launched multiple research efforts to develop tailored vaccines against COVID-19 variants since their emergence, including the Beta, Gamma and Delta variants. All projects are going on in an orderly way, some of which have already applied for clinical trials.

Please feel free to contact us by sending your questions to or commenting on China Daily app. We will ask experts to answer them.

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