FILE PHOTO: A man works in the packaging facility of Chinese vaccine maker Sinovac Biotech, developing an experimental coronavirus disease (COVID-19) vaccine, during a government-organized media tour in Beijing, China, September 24, 2020. Sinovac Biotech's experimental COVID-19 vaccine CoronaVac triggered a quick immune response but the level of antibodies produced was lower than in people who had recovered from the disease, preliminary trial results showed on Wednesday. Sinovac is currently running three Phase III trials in Indonesia, Brazil and Turkey. REUTERS/Thomas Peter/File Photo

FILE PHOTO: A man works in a laboratory of Chinese vaccine maker Sinovac Biotech, developing an experimental coronavirus disease (COVID-19) vaccine, during a government-organized media tour in Beijing, China, September 24, 2020. While the early to mid-stage trials were not designed to assess the efficacy of CoronaVac, researchers said it could provide sufficient protection, based on their experience with other vaccines and data from preclinical studies with macaques. REUTERS/Thomas Peter/File Photo

A worker performs a quality check in the packaging facility of Chinese vaccine maker Sinovac Biotech, developing an experimental coronavirus disease (COVID-19) vaccine, during a government-organized media tour in Beijing, China, September 24, 2020. The study comes hot on the heels of upbeat news this month from U.S. drugmakers Pfizer and Moderna as well as Russia that showed their experimental vaccines were over 90% effective based on interim data from large, late-stage trials. REUTERS/Thomas Peter

A man works in the packaging facility of Chinese vaccine maker Sinovac Biotech, developing an experimental coronavirus disease (COVID-19) vaccine, during a government-organized media tour in Beijing, China, September 24, 2020. CoronaVac and four other experimental vaccines developed in China are currently undergoing late-stage trials to determine their effectiveness in preventing COVID-19. REUTERS/Thomas Peter

A worker performs a quality check in the packaging facility of Chinese vaccine maker Sinovac Biotech, developing an experimental coronavirus disease (COVID-19) vaccine, during a government-organized media tour in Beijing, China, September 24, 2020. The Sinovac findings, published in a peer-reviewed paper in medical journal The Lancet Infectious Diseases, came from results in Phase I and Phase II clinical trials in China involving more than 700 participants. REUTERS/Thomas Peter

FILE PHOTO: A display shows packages of vaccine candidate for SARS-CoV-2 by Sinovac Biotech during a government-organized media tour showcasing the company's development of a coronavirus disease (COVID-19) vaccine candidate in Beijing, China, September 24, 2020. Sinovac Biotech's experimental COVID-19 vaccine CoronaVac triggered a quick immune response but the level of antibodies produced was lower than in people who had recovered from the disease, preliminary trial results showed on Wednesday. Sinovac is currently running three Phase III trials in Indonesia, Brazil and Turkey. REUTERS/Thomas Peter/File Photo