[Sinovac Reports Unaudited Second Quarter 2010 Financial Results - Conference call scheduled for Monday, August 16, 2010 at 8:00 AM EDT — Beijing — August 16, 2010 — Sinovac Biotech Ltd. ( NASDAQ: SVA), a leading China-based vaccine manufacturer , announced today its un audited financial results for the three-month and six-month periods ended June 30, 2010. Financial Highlights ·] [1 -32371 SINOVAC BIOTECH LTD. No. 39 Shangdi Xi Road Haidian District Beijing 100085, People’s Republic of China Form 20-F x Form 40-F o o o SINOVAC BIOTECH LTD.]

[Sinovac Holds 2010 Annual Meeting of Shareholders Beijing — July 15, 2010 — Sinovac Biotech Ltd. (Nasdaq: SVA), a leading developer and provider of vaccines in China, announced today that it held its 2010 Annual Meeting of Shareholders on Thursday, July 15, 2010 at 9:00 a.m. Beijing Time. The required quorum, a majority of the common shares outstanding, was voted] [1 -32371 SINOVAC BIOTECH LTD. No. 39 Shangdi Xi Road Haidian District Beijing 100085, People’s Republic of China Form 20-F x Form 40-F o o o SINOVAC BIOTECH LTD.]

[IMPORTANT REMINDER July 1, 2010 Dear Shareholder: We have previously mailed to you proxy materials relating to the Annual Meeting of Shareholders scheduled to be held on Thursday, July 15, 2010. According to our latest records, we have not received your proxy card for this important meeting. Regardless of the number of shares you own, it is important that they] [IMPORTANT ANNUAL MEEING IS SCHEDULED FOR JULY 15, 2010 PLEASE INSTRUCT YOUR BROKER TO VOTE TODAY! July 1, 2010 Dear Fellow Shareholder: Your vote is extremely important, regardless of the number of shares that you own. Please instruct your broker how to vote your shares today to avoid additional solicitation costs. According to our latest records, your broker has not] [1 -32371 SINOVAC BIOTECH LTD. No. 39 Shangdi Xi Road Haidian District Beijing 100085, People’s Republic of China Form 20-F x Form 40-F o o o SINOVAC BIOTECH LTD.]