They Relied on Chinese Vaccines. Now They’re Battling Outbreaks. - The New York Times

Now, examples from several countries suggest that the Chinese vaccines may not be very effective at preventing the spread of the virus, particularly the new variants.

And all four are mostly using shots made by two Chinese vaccine makers, Sinopharm and Sinovac Biotech.

“If the vaccines are sufficiently good, we should not see this pattern,” said Jin Dongyan, a virologist at the University of Hong Kong.

And as more citizens question the efficacy of Chinese doses, persuading unvaccinated people to line up for shots may also become more difficult.

“Relevant reports and data also show that many countries that use Chinese-made vaccines have expressed that they are safe and reliable, and have played a good role in their epidemic prevention efforts,” the ministry said.

No vaccine fully prevents transmission, and people can still fall ill after being inoculated, but the relatively low efficacy rates of Chinese shots have been identified as a possible cause of the recent outbreaks.

The Pfizer-BioNTech and Moderna vaccines have efficacy rates of more than 90 percent.

A variety of other vaccines — including AstraZeneca and Johnson & Johnson — have efficacy rates of around 70 percent.

The Sinopharm vaccine developed with the Beijing Institute of Biological Products has an efficacy rate of 78.1 percent; the Sinovac vaccine has an efficacy rate of 51 percent.

The Chinese companies have not released much clinical data to show how their vaccines work at preventing transmission.

On Monday, Shao Yiming, an epidemiologist with the Chinese Center for Disease Control and Prevention, said China needed to fully vaccinate 80 to 85 percent of its population to achieve herd immunity, revising a previous official estimate of 70 percent.

William Schaffner, medical director of the National Foundation for Infectious Diseases at Vanderbilt University, said the efficacy rates of Chinese shots could be low enough “to sustain some transmission, as well as create illness of a substantial amount in the highly vaccinated population, even though it keeps people largely out of the hospital.”.

Data from Mongolia showed that the Sinopharm vaccine was actually more protective than the doses developed by AstraZeneca and Sputnik, a Russian vaccine, according to the Health Ministry.

Nikolai Petrovsky, a professor at the College of Medicine and Public Health at Flinders University in Australia, said that with all of the evidence, it would be reasonable to assume the Sinopharm vaccine had minimal effect on curbing transmission.

A major risk with the Chinese inoculation is that vaccinated people may have few or no symptoms and still spread the virus to others, he said.

Ten of them had taken the Chinese-made vaccine, the association said.