Explainer: Are Chinese COVID-19 shots effective against the Delta variant?

Photo: Marko Djurica – Reuters


Many countries from China to Indonesia and Brazil rely heavily on Chinese vaccines to inoculate their people against COVID-19, but there are growing concerns about whether they provide enough protection against the Delta variant, first identified in India.

By Reuters – Roxanne Liu and Ryan Woo

Jun 29, 2021

Below are views from China’s health experts about the effectiveness of home-grown vaccines against the Delta, which is becoming the globally dominant variant, and virus preventive measures China is taking.

Do Chinese Vaccines work against Delta?

China has not provided vaccine effectiveness results against the variant based on large-scale data in clinical trials or real-world use, nor offered detailed information from lab tests, but Chinese experts are urging people to get inoculated as soon as possible.

Researchers found that Chinese vaccines are somewhat effective in reducing the risk of symptomatic and severe cases caused by Delta, Zhong Nanshan, a epidemiologist who helped shape China’s COVID-19 response, told reporters.

It is based on analysis of infections in Guangzhou city, and Zhong told Reuters the results are preliminary and the sample size is small.

Sinovac spokesman Liu Peicheng told Reuters preliminary results based on blood samples from those vaccinated with its shot showed a three-fold reduction in neutralizing effect against the Delta.

Antibodies triggered by two Chinese vaccines are less effective against the Delta compared with other variants, Feng Zijian, former deputy director at the Chinese Center for Disease Control and Prevention, told state media last week.

Feng did not provide details including the name of the two vaccines.

The shots could still offer protection, since none of those vaccinated in southern Guangdong province, where China’s first cases of the Delta variant were found, developed severe symptoms. All severe cases are from unvaccinated people.

Jin Dong-Yan, a virologist at the University of Hong Kong, said Feng’s comment alone is not enough to back up the claim that Chinese vaccines are effective against severe cases, as more data is needed.

Indonesia, which has reported record daily cases recently due to a surge in the Delta variant, saw hundreds of medical workers infected by the COVID-19 despite being vaccinated with Sinovac’s shot, officials said earlier this month.

Read More: Reuters – Explainer: Are Chinese COVID-19 shots effective against the Delta variant?

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