Report of Foreign Issuer (6-k)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of April 2015

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Commission File Number: 001-32371

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SINOVAC BIOTECH LTD.

No. 39 Shangdi Xi Road

Haidian District

Beijing 100085, People’s Republic of China

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F:

Form 20-F

Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):________________

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):________________

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	SINOVAC BIOTECH LTD.



	By:		/s/ Weidong Yin
	Name: Weidong Yin
	Title: Chairman and Chief Executive Officer

Date: April 15, 2015

Exhibit Index

Exhibit 99.1 – Press Release

Exhibit 99.2 – Press Release

Exhibit 99.3 – Press Release

Exhibit 99.1

Sinovac Provides Updates on Pipeline Vaccines

BEIJING, March 17, 2015 /PRNewswire/ -- Sinovac Biotech Ltd. (SVA), a leading provider of biopharmaceutical products in China, today provided updates on the Company's pipeline vaccines.

EV71 vaccine. The Company submitted supplementary documentation to the China Food and Drug Administration (CFDA) at the end of January 2015, as required following review of the new drug application (NDA) by an expert panel in November 2014. The CFDA has begun its review of the supplementary documentation. Sinovac maintains regular communication with relevant departments of CFDA, in order to be prepared for the upcoming on-site inspection, sample testing, and production and lot release after the product is commercialized. Once the on-site inspection and sample testing are successfully completed, Sinovac will receive the new drug certificate, production license and GMP license to begin commercial production of its EV71 vaccine.

EV71 is a virus that causes hand, foot and mouth disease (HFMD) and is the primary cause of most severe and fatal cases of hand, foot and mouth disease (HFMD) in China. According to the Chinese CDC, there were approximately 2.78 million reported cases of HFMD in 2014 and 508 fatal cases.

Please see the Company's 20-F filing on April 16, 2014 at www.SEC.gov for a complete outline of the NDA process.

Other Pipeline Vaccines

Pneumococcal 23-valent polysaccharide vaccine (PPV). The Company obtained its clinical trial license in May 2014. Sinovac is currently completing clinical trial preparations and expects to start trials in the first half of 2015.

Varicella vaccine. The Company is currently preparing supplementary material for the clinical trial application, following review by an expert panel in November 2014. The Company expects to receive its clinical trial license in 2015. Sinovac filed the clinical trial application with the CFDA in January 2013.

Pneumococcal 13-valent conjugate vaccine (PCV). The Company obtained its clinical trial license in January 2015, having filed its application with the CFDA in March 2011. PCV is targeted for children under two years old. Sinovac will finalize its clinical trial protocols based on Good Clinical Practice (GCP) and related technical guidelines and initiate production and testing for vaccines to be used in clinical trial accordingly. The Company is required to commence the trials within three years after the license is issued.

Sabin-inactivated polio vaccine (sIPV). The clinical trial application for the vaccine was accepted by Beijing Food and Drug Administration in October 2014 and is under review by the CDE.

Hepatitis B vaccine and new generation of hepatitis A & B vaccine. The Company has completed pre-clinical studies for its proprietary hepatitis B vaccine and filed a clinical trial application in December 2014. Simultaneously, Sinovac is developing a new generation of its hepatitis A & B combination vaccine based on its individual hepatitis A and B vaccines. The new generation combination vaccine will contain a higher dosage of the hepatitis B component, 10ugand 20ug for pediatric and adult formulations, respectively, to enhance the vaccine's immunogenicity. And the clinical trial application for the combined vaccine was submitted in December 2014.

Rubella vaccine. The Company obtained the clinical trial license in December 2014. This vaccine is expected to be developed as a measles, mumps and rubella (MMR) combination vaccine. The Company filed its application for clinical trial with the CFDA in April 2011.

Mr. Yin concluded, "The continued advancement of our vaccine pipeline is evidence of our strong R&D capabilities. With these capabilities and commercial execution strategies, Sinovac is well positioned to grow over the long-term. I am confident that our pipeline will continue to progress as we work towards our mission of providing protection against infectious diseases in China and other emerging markets."

About Sinovac

Sinovac Biotech 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 hepatitis A and B, seasonal influenza, H5N1 pandemic influenza (avian flu), H1N1 influenza (swine flu), mumps and canine rabies. 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 government stockpiling program. Sinovac has filed a new drug application with the China Food & Drug Administration for its proprietary enterovirus 71 vaccine, having been proven effective in preventing hand, foot and mouth disease in infants and children during its Phase III clinical trial. The Company is currently developing a number of new products including a Sabin-strain inactivated polio vaccine, pneumococcal polysaccharides vaccine, pneumococcal conjugate vaccine and varicella vaccine. Sinovac primarily sells its vaccines in China, while also exploring growth opportunities in international markets. The Company has exported select vaccines to Mexico, Mongolia, Nepal, and the Philippines, and was recently granted a license to commercialize its hepatitis A vaccine in Chile. For more information, please visit the Company's website at www.sinovac.com.

Contact

Sinovac Biotech Ltd.

Helen Yang / Chris Lee

Tel: +86-10-8279-9659 / 9696

Fax: +86-10-6296-6910

Email: ir@sinovac.com

ICR Inc.

Bill Zima

U.S: 1-646-308-1707

Email: william.zima@icrinc.com

Exhibit 99.2

Sinovac to Participate in China Medical and Healthcare Investment Conference

Beijing, March 18,2014/PRNewswire/--Sinovac Biotech Ltd.(NASDAQ:SVA), a leading provider of biopharmaceutical products in China, today announced that the Company will participate in the China Medical and Healthcare Investment Conference sponsored by T.H capital and Dong Xing Security, to be held at China World Hotel from March 23 to March 25. The Company will present from 09:30 am to 10:30am on March 25, and conduct one-on-one meetings during the course of the day. Any parties interested in scheduling a meeting with the Company at this event should contact T.H capital or Dong Xing Security.

About Sinovac

Contact

Sinovac Biotech Ltd.

Helen Yang / Chris Lee

Tel: +86-10-8279-9659 / 9696

Fax: +86-10-6296-6910

Email: ir@sinovac.com

ICR Inc.

Bill Zima

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

Email: william.zima@icrinc.com

Exhibit 99.3

Sinovac to Host Conference Call to Report Fourth Quarter and Full Year 2014 Unaudited Financial Results

BEIJING, April 10, 2015 -- Sinovac Biotech Ltd. (Nasdaq: SVA), a leading provider of biopharmaceutical products in China, today announced that it will release its unaudited financial results for the fourth quarter and full year, ended December 31, 2014, before market opens on Monday, April 20, 2015. The Company will host a conference call on Monday, April 20, 2015, at 8:00 a.m. EDT (Monday, April 20, 2015 at 8:00 p.m. China Standard Time) to review the Company's financial results and provide an update on recent corporate developments.

To access the conference call, please dial 1-877-407-9039 (USA) or 1-201-689-8470 (International). A replay of the call will be available from 11 a.m. EDT on April 20, 2015 through May 4, 2015. To access the replay, please dial 1-877-870-5176 (USA) or 1-858-384-5517 (International) and reference the replay pin number 13607019.

A live audio webcast of the call will also be available on the Investor Relations section of the Company’s website at www.sinovac.com. A webcast replay will be available on the Company’s website for 30 days following the call.

About Sinovac