The European Medicines Agency (EMA) said on Thursday its decision to start the review was based on preliminary results from laboratory and clinical studies, involving animals and humans, which suggest the vaccine produces an immune response against the coronavirus.
“These studies suggest that the vaccine triggers the production of antibodies … and may help protect against disease,” the agency said in a statement.
Sinovac’s vaccine contains inactivated or dead versions of the SARS-CoV-2 virus to help the human body’s immune system make antibodies.
It has shown effectiveness rates between 50 percent and 90 percent in different studies.
The shot is currently licensed for use in China, Indonesia, Brazil, and Turkey.
In April, Sinovac said its third plant for producing its vaccine, under the CoronaVac brand in some areas, was ready, doubling its annual capacity to two billion doses.
The company said more than 200 million doses of the Sinovac vaccine have been delivered worldwide.
Sinovac is the first Chinese vaccine that the EMA is studying in real time.
The agency is also conducting ongoing reviews of three other vaccines: one developed by German biotech company CureVac, another by US company Novavax, and a third – Russian Sputnik V.
Continuous reviews aim to speed up the approval process by allowing researchers to submit results in real time before final trial data becomes available.
The agency said its experts would assess the data “to decide whether the benefits outweigh the risks” of Sinovac’s shot.
No Phase 3 vaccine study data has yet been published in peer-reviewed journals.
The most closely watched research involved around 12,000 health workers in Brazil, where researchers reported 50.7% effectiveness against symptomatic COVID-19 and much stronger protection against serious illness.
The ongoing review of the EMA will continue until “sufficient evidence is available for a formal marketing authorization application,” the agency said, adding that it could not predict the deadlines and that no request to obtain such an authorization for the Sinovac vaccine has yet been submitted.
The Amsterdam-based agency’s announcement came a day after a senior World Health Organization (WHO) official said the United Nations body was to decide this week to approve two Chinese vaccines. COVID-19 for emergency use.
Such approval would mark the first time that a Chinese vaccine would be granted a so-called emergency use list from the United Nations health agency, and would trigger a wider rollout of Chinese vaccines that are already in use in some countries beyond China.