Sinovac Announces Commencement of Phase I Human Clinical Trial for Vaccine Candidate Against COVID-19 BEIJING --(BUSINESS WIRE)

Commencement of Phase I Human Clinical Trial for

Vaccine Candidate Against COVID-19

BEIJING --(BUSINESS WIRE)-- April 17, 2020--

Sinovac Biotech Ltd. (NASDAQ:SVA) ("Sinovac" or the "Company"), a leading provider of biopharmaceutical

products in China, today announced that the Company has commenced Phase I clinical trial, a randomized, double-blinded, placebo

controlled study, for its vaccine candidate against COVID-19. Enrollment of the first group of volunteers and the first dose of

vaccination for these volunteers have been completed.

This study is to evaluate the safety, tolerance,

and preliminary immunogenicity of the Company's SARS-CoV-2 vaccine by vaccinating 144 healthy adults, aged from 18 to 59,

with two different dosages of the vaccine candidate. Two-thirds of the volunteers will be vaccinated with the investigational vaccine

while one-third of volunteers will be administered with the placebo. The trial is being conducted in Jiangsu Province.

On April 13, 2020, the randomized, double-blinded, placebo-controlled

phase I/II clinical trials of the inactivated SARS-CoV-2 vaccine developed by Sinovac was approved by China's National Medical

Products Administration (NMPA) to evaluate the vaccine candidate's safety and immunogenicity.

Mr. Weidong Yin, Chairman, President and CEO said, "The

vaccine is critical to the eventual prevention of the spread of COVID-19. Commencing our human trial is another milestone achieved

by our scientists together with our vaccine development partners. Sinovac will accelerate the progress of our research in order

to support the worldwide fight against COVID-19."

Ltd. is a China-based biopharmaceutical company that focuses on the research, development, manufacturing and commercialization

of vaccines that protect against human infectious diseases. Sinovac's product portfolio includes vaccines against enterovirus71

(EV71), hepatitis A and B, seasonal influenza, H5N1 pandemic influenza (avian flu), H1N1 influenza (swine flu), varicella vaccine

and mumps. Healive, the hepatitis A vaccine manufactured by the Company, has passed the assessment under WHO prequalification

procedures in 2017. The EV71 vaccine, an innovative vaccine developed by Sinovac against hand foot and mouth disease caused by

EV71, was commercialized in China in 2016. In 2009, Sinovac was the first company worldwide to receive approval for its H1N1 influenza

vaccine, which it has supplied to the Chinese Government's vaccination campaign and stockpiling program. The Company is also the

only supplier of the H5N1 pandemic influenza vaccine to the Chinese Government's stockpiling program. The Company is developing

a number of new products including a Sabin-strain inactivated polio vaccine, pneumococcal polysaccharides vaccine, a quadrivalent

influenza vaccine and a SARS-CoV-2 (commonly referred to as COVID-19) vaccine. Sinovac primarily

sells its vaccines in China, while also exploring growth opportunities in international markets. The Company is registering its

products in over 30 countries outside of China. For more information please see the Company's website at www.sinovac.com.

Safe Harbor Statement

release contains "forward-looking statements" within the meaning of the United States federal securities laws. Such

statements involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity,

performance or achievements to differ materially from any future results, levels of activity, performance or achievements expressed

or implied by these forward-looking statements. Factors that might cause such a difference include our inability to compete successfully

in the competitive and rapidly changing marketplace in which we operate, failure to retain key employees, cancellation or delay

of projects, failure to satisfy regulatory and other requirements, disapproval or delay in approval of new products by regulatory

bodies, disruptions to our operations, the results of any pending litigation (including litigation relating to the 2018 annual

general meeting, the validity of our Rights Agreement, and the issuance of the Exchange Shares), Nasdaq's halt in trading

of the Company's securities and any future action taken by Nasdaq regarding the trading of the Company's securities,

the effects of natural disasters, pandemics and outbreaks of contagious diseases and other adverse public health developments,

such as SARS-CoV-2 (commonly referred to as COVID-19), and adverse general economic conditions

in China, the United States and elsewhere. These risks and other factors include those listed under "Risk Factors"

and elsewhere in our Annual Report on Form 20-F as filed with the Securities and Exchange Commission. In some cases, you can identify

forward-looking statements by terminology such as "may," "will," "should," "expects,"

"intends," "plans," "anticipates," "believes," "estimates," "predicts,"

"potential," "continue," or the negative of these terms or other comparable terminology. Although we believe

that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, levels of

activity, performance or achievements. The Company assumes no obligation to update the forward-looking information contained in

Sinovac Biotech Ltd.

Tel: +86-10-8279-9871 or

Fax: +86-10-6296-6910

Email: ir@sinovac.com

U.S.: 1-646-308-1707

Email: william.zima@icrinc.com