China's Sinovac COVID-19 Vaccine With 50% Efficacy Rate Gets WHO Approval

China's Sinovac COVID-19 vaccine, with an efficacy rate of 50 percent, was approved by the World Health Organization (WHO) on Tuesday for emergency use in adults 18 and older.

Data reviewed by WHO experts showed that two doses of the Sinovac vaccine prevented half of those who received the jabs from getting COVID-19, the Associated Press reported. Sinovac's authorization is the second approval by the WHO for a Chinese vaccine following China' Sinopharm shot approval last month.

"Nevertheless, WHO is not recommending an upper age limit for the vaccine," the WHO said in a statement on Sinovac's authorization. Since fewer older adults participated in the research the agency reviewed, they could not estimate the vaccine's efficacy for those over 60.

WHO added that research on Sinovac's use in other countries "suggest the vaccine is likely to have a protective effect in older persons." In April, Brazilian scientists published a study that showed Sinopharm had an efficacy rate over 50 percent while a study in Chile found the vaccine had an efficacy rate of 67 percent.

For more reporting from the Associated Press, see below.

China's Sinovac COVID-19 Vaccine
A health personnel inoculates a man with the second dose of China's Sinovac coronavirus vaccine at the Holy Redeemer Church in Bangkok on May 30, 2021. The Sinovac vaccine has been approved by the World Health Organization for emergency use in adults 18 and older. Romeo Gacad/AFP via Getty Images

WHO has also licensed vaccines developed by Pfizer-BioNTech, AstraZeneca, Moderna and Johnson & Johnson.

WHO's authorization means the vaccine can be bought by donors and other U.N. agencies for use in poorer countries, including in the U.N.-backed initiative to distribute COVID-19 vaccines globally known as COVAX. The effort has been slowed considerably after its biggest supplier in India said it would not be able to provide any more vaccines until the end of the year due to the latest surge of new infections now ravaging India.

To date, there is no confirmed deal for Sinovac doses with COVAX.

In May, Europe's drug regulator began an expedited review process for the Sinovac vaccine, but it's unclear when a decision might be made about its possible authorization for the 27-nation bloc.

Hundreds of millions of Chinese vaccines have already been delivered to dozens of countries around the world through bilateral deals, as many nations scrambled to secure supplies after rich countries reserved the vast majority of supplies from Western pharmaceutical makers.

While China has five vaccine shots in use, the majority of its exports abroad come from two companies: Sinopharm and Sinovac. The Chinese vaccines are "inactivated" vaccines, made with killed coronavirus.

Most other COVID-19 vaccines being used around the world, particularly in the West, are made with newer technologies that instead target the "spike" protein that coats the surface of the coronavirus.

Sinovac COVID-19 Vaccine
In this Friday, May 28, 2021 file photo, a healthcare worker prepares a dose of the Sinovac COVID-19 vaccine during a vaccination session for medical staff who work at private clinics in Caracas, Venezuela. The World Health Organization has issued an emergence use listing for the COVID-19 vaccine made by Sinovac in adults aged 18 and over, the second such authorization it has granted to a Chinese company. Matias Delacroix/AP Photo