Then, on Jan. 12, scientists said it had an efficacy rate of just over 50 percent, once people who experienced mild symptoms were included. That level is a hair above the threshold set by the World Health Organization to consider a vaccine effective. In a news conference last week, Sinovac’s chief executive officer, Yin Weidong, reiterated that the vaccine is 100 percent effective in preventing severe cases. He said the lower efficacy rate was because the trial was focused on health care workers, who had a higher propensity of contracting Covid-19 than the general population.
Jair Bolsonaro, Brazil’s president and a critic of both China and its Covid-19 vaccines, pounced on the data. On Jan. 13, he mocked the vaccine’s efficacy rate, asking a supporter: “Is that 50 percent good?”
To be sure, the Chinese vaccines have a big appeal to many countries. More than 40 countries have expressed an interest in importing Chinese vaccines, according to China’s foreign ministry. Several world leaders, including President Reccep Tayyip Erdogan of Turkey and President Joko Widodo of Indonesia, have gotten a Sinovac vaccine.
But the spotty and inconsistent disclosures about the vaccines remain a problem. In the case of Sinopharm, the company said a vaccine candidate made by its Beijing Institute of Biological Products arm had an efficacy rate of 79 percent, but it did not disclose crucial details. Sinopharm didn’t respond to a request for comment.
In Hong Kong, a special administration region of China that has ordered 7.5 million doses of the Sinovac vaccine, officials have not received an application for emergency distribution nor any data from the Chinese company.
“Whether it is because they are not making enough or if they have no plans to send the vaccines to Hong Kong yet, I don’t know,” said Dr. Lau Chak Sing, who heads a Hong Kong government advisory panel on Covid-19 vaccines.