Exhibit 1

SINOVAC BIOTECH LTD.

(Incorporated in Antigua and Barbuda)

(NASDAQ Ticker: SVA)

PROXY STATEMENT

for

SPECIAL MEETING OF SHAREHOLDERS
to Be Held on Tuesday, July 8, 2025
(or any adjourned or postponed meeting thereof)

This proxy statement is furnished in connection with the solicitation of proxies by SAIF Partners IV L.P. (the “SAIF Partners,” “we,” “our,” or “us”) in respect of the special meeting of shareholders of Sinovac Biotech Ltd. (the “Company”) to be held at Stapleton Chambers Inc., Suite No. 2, Stapleton House, Stapleton Lane, Saint John’s, Antigua and Barbuda with online participation made available via a secure videoconferencing platform on Tuesday, July 8, 2025 at 8:00 p.m. Atlantic Standard Time (Wednesday, July 9, 2025 at 8:00 a.m. China Standard Time), and for any adjourned, postponed, continued, or rescheduled meeting thereof (the “Special Meeting ”), for the purposes of removing and electing certain individuals from and to the board of directors of the Company (the “Board”).

THIS SOLICITATION IS BEING MADE BY SAIF PARTNERS AND NOT ON BEHALF OF THE BOARD.

SAIF Partners first became a beneficial owner of common shares of the Company in October 2010 and has been a shareholder of the Company for over 15 years. Currently, we beneficially own 10,780,820 common shares of the Company, representing approximately 15% of all outstanding common shares of the Company.

SAIF Partners is a leading Asian private equity firm with cumulative assets under management of over $4 billion. SAIF Partners is an active lead investor working closely with its portfolio companies to develop their business both organically and through acquisitions, seeking synergistic cooperation among them, as well as enhancing shareholder value via promotion of good corporate governance and best management practices.

We are soliciting proxies to elect Simon Anderson, Shan Fu, Shuge Jiao, Chiang Li, Yuk Lam Lo, Yumin Qiu, Yu Wang, Rui-Ping Xiao, Andrew Y Yan, and Weidong Yin (each, a “Nominee,” collectively, “Nominees”) to the Board, and to remove David Guowei Wang, Sven H. Borho, and any other person or persons elected or appointed to the Board without shareholders’ approval after February 8, 2025 and up to and including the date of the Special Meeting (collectively, “Existing Directors”) from the Board and each applicable committee thereof.

We are soliciting your vote because we believe that the Existing Directors do not represent the interests of all of the Company’s shareholders and have not been acting in the best interest of the Company’s shareholders since they took office in February 2025, and they do not have the experience and industry knowledge required to lead the Company to enhance shareholder value.

We believe our Nominees comprise a well-balanced, highly qualified, independent and diversified Board with extensive industry knowledge, experience and insights beneficial to the Company, and that they would fairly represent the interests of all shareholders of the Company. We also believe that the Nominees, if elected, would work expeditiously towards resumption of trading of the Company’s common shares and approving and executing a plan to distribute dividends in addition to the one the current Board has proposed to distribute.

Your vote is important to achieve the goals mentioned above and further elaborated below. Accordingly, if the common shares of the Company are held in your own name, you are urged to sign and return the accompanying GOLD proxy card or vote online or by telephone by following the instruction on the enclosed GOLD proxy card or GOLD voting instruction form, whether or not you plan to attend the Special Meeting.

If you hold the common shares of the Company in “street name” with a bank, brokerage firm, dealer, trust company or other institution or nominee, only they can exercise your right to vote with respect to your common shares and only upon receipt of your specific instructions. Accordingly, it is critical that you promptly give instructions to your bank, brokerage firm, dealer, trust company or other institution or nominee on how to vote the shares by completing, signing, dating and returning each GOLD voting instruction form you receive, or by voting online or by telephone as described on your GOLD voting instruction form.

Sodali & Co (“Sodali”) is assisting us with our effort to solicit proxies. If you have any questions or require assistance in authorizing a proxy or voting your common shares, please contact:

Sodali & Co

430 Park Avenue, 14^th Floor

New York, NY 10022

Call Toll-Free in North America: (800) 662-5200

Outside of North America Call Collect: (203) 658-9400

Email: SAIF@info.sodali.com

PLEASE DO NOT RETURN ANY PROXY CARD YOU MAY RECEIVE FROM THE COMPANY OR OTHERWISE AUTHORIZE A COMPANY’S PROXY TO VOTE YOUR COMMON SHARES AT THE SPECIAL MEETING, NOT EVEN AS A PROTEST VOTE. IF YOU HAVE ALREADY SENT A PROXY CARD TO THE COMPANY OR OTHERWISE AUTHORIZED A COMPANY’S PROXY TO VOTE YOUR COMMON SHARES AT THE SPECIAL MEETING, IT IS NOT TOO LATE TO CHANGE YOUR VOTE BY USING THE ENCLOSED GOLD PROXY CARD. ONLY YOUR LATEST DATED PROXY WILL BE COUNTED.

BACKGROUND TO THIS SOLICITATION

The following is a chronology of material events leading up to this proxy solicitation. All dates and times are United States Eastern Time.

REASONS FOR THE SOLICITATION

It is Critical to Have a Board That Represents the Best Interests of All Shareholders of the Company to Maximize Value for All Shareholders

Reasons for Removing the Existing Directors

We believe the current Board lacks the qualifications necessary to accomplish the goals outlined above for the following reasons.

Reasons for Electing the Nominees

We believe that the election of the Nominees is in the best interests of the Company and its shareholders.

FORWARD-LOOKING STATEMENTS AND INFORMATION

Certain statements and information included, attached to or incorporated by reference, if any, into this proxy statement may contain “forward-looking statements” or “forward-looking information” within the meaning of applicable securities laws (collectively, the “forward-looking statements”), including, but not limited to, statements regarding the Special Meeting, the solicitation of proxies and voting in respect of the Special Meeting, SAIF Partners, the intentions of SAIF Partners or SAIF Partners’ Nominees, the impact of the SAIF Partners’ Nominees, if elected, on the financial condition, operations, business and strategies of the Company and its shareholder value, the composition of the Board and the future plans or prospects of the Company. All statements and information, other than statements of historical fact, included or incorporated by reference into this proxy statement are forward-looking statements, including, without limitation, statements regarding activities, events or developments that SAIF Partners expects or anticipates may occur in the future. Such statements reflect SAIF Partners’ current views and intentions with respect to future events and are subject to certain risks, uncertainties and assumptions. Forward-looking statements can usually be identified by the use of forward-looking words such as “will”, “expect”, “intend”, “plan”, “hope”, “anticipate”, “believe” or “continue” or similar words and expressions or the negative thereof. There can be no assurance that the plans, intentions or expectations upon which such forward-looking statements and information are based will occur or, even if they do occur, will result in the performance, events or results expected.

We caution readers of this proxy statement not to place undue reliance on forward-looking statements and information contained in the proxy statement.

Shareholders are cautioned that all forward-looking statements involve known and unknown risks and uncertainties. We urge you to carefully consider those risks and uncertainties. The forward-looking statements contained in this proxy statement are expressly qualified in their entirety by this cautionary statement. SAIF Partners do not assume responsibility for the accuracy or completeness of the forward-looking statements. The forward-looking statements included in this proxy statement are made as of the date of this proxy statement and SAIF Partners undertake no obligation to publicly update or revise such forward-looking statements to reflect new information, subsequent events or otherwise, except as required by applicable law.

Important Notice Regarding the Availability of Proxy Materials for the Special Meeting:

REGARDLESS OF WHETHER YOU INTEND TO ATTEND THE SPECIAL MEETING, YOUR PROMPT ACTION IS IMPORTANT. MAKE YOUR VIEWS CLEAR TO THE COMPANY BY VOTING TODAY ON THE ENCLOSED GOLD PROXY CARD TODAY.

YOUR VOTE IS IMPORTANT, NO MATTER HOW MANY OR HOW FEW COMMON SHARES YOU OWN.

GENERAL INFORMATION ABOUT THIS PROXY STATEMENT AND VOTING

Resolutions to be Voted For

We are asking you to vote on the GOLD proxy card at the Special Meeting as follows:

Information of Nominees

We are proposing that Simon Anderson, Shan Fu, Shuge Jiao, Chiang Li, Yuk Lam Lo, Yumin Qiu, Yu Wang, Rui-Ping Xiao, Andrew Y Yan, and Weidong Yin be elected as directors of the Company to serve on the Board until the next annual meeting or until their respective successors are duly elected and qualified.

Set forth below are the biographs of certain Nominees, including their names, professional and educational backgrounds. The Nominees are listed alphabetically by their last name.

We expect the Nominees for whom we seek proxies to vote will be willing to serve as directors if any or all of such Nominees are elected to the Board.

Record Date, Outstanding Shares, and Voting Rights

As of the close of business on May 19, 2025, the record date for the Special Meeting (the “Record Date”), the Company had 71,860,702 common shares outstanding, $0.001 par value per share, being the class of securities entitled to vote at the Special Meeting. Each common share entitles its holder to one vote.

Appointing or Revoking Proxies

We are asking you to appoint SAIF Partners IV L.P. as your proxy holder to vote your common shares at the Special Meeting. In doing so, you may complete, sign, and date the enclosed GOLD proxy card, and return it in the enclosed self-addressed, prepaid envelope or you may vote online or by telephone (instructions are on your GOLD proxy card or GOLD voting instruction form). Giving us your proxy means you authorize the proxy holder to vote your common shares at the Special Meeting, according to the directions you provide.

IF YOU RETURN A VALID GOLD PROXY CARD AND NO SPECIFICATION IS MADE, THE COMMON SHARES WILL BE VOTED: (I) “FOR” THE REMOVAL OF EACH OF DAVID GUOWEI WANG AND SVEN H. BORHO, AND OTHER PERSON OR PERSONS ELECTED OR APPOINTED TO THE BOARD OF DIRECTORS OF THE COMPANY WITHOUT SHAREHOLDERS' APPROVAL AFTER FEBRUARY 8, 2025 AND UP TO AND INCLUDING THE DATE OF THE SPECIAL MEETING FROM THE BOARD AND EACH APPLICABLE COMMITTEE THEREOF; (II) “FOR” SIMON ANDERSON, SHAN FU, SHUGE JIAO, CHIANG LI, YUK LAM LO, YUMIN QIU, YU WANG, RUI-PING XIAO, ANDREW Y YAN, AND WEIDONG YIN AS DIRECTORS; AND (III) IN THE PROXY HOLDER'S DISCRETION AS TO OTHER MATTERS THAT MAY PROPERLY COME BEFORE OR DURING THE SPECIAL MEETING.

Except as set forth in this proxy statement, we do not know of any other matters to be presented for approval by the shareholders at the Special Meeting. Unless you indicate otherwise on the Gold proxy card, you also authorize your proxy holder to vote your common shares in their discretion on any matters not known by us at the time this proxy statement was printed and that, under the Articles of Incorporation and By-Laws of the Company, may be properly presented for action by the shareholders before or at the Special Meeting.

If you hold the common shares in “street name” with a bank, brokerage firm, dealer, trust company or other institution or nominee, only they can exercise your right to vote with respect to your common shares and only upon receipt of your specific instructions. Accordingly, please promptly give instructions to your bank, brokerage firm, dealer, trust company or other institution or nominee using the enclosed GOLD voting instruction form. Please also refer to the GOLD voting instruction form for information on voting online or by telephone.

If you desire to revoke your proxy, you may do so at any time before it is voted. Written notice of such revocation may be forwarded directly to Sodali. Alternatively, you may attend and vote in person at the Special Meeting, your proxy will be automatically revoked.

Required Quorum for the Special Meeting

In order to carry on the business of the Special Meeting, there must be a quorum. This means holders of record of at least a majority of the Company’s common shares must be represented at the time when the Special Meeting proceeds to business, either by proxy or in person. Abstentions, votes withheld and broker “non-votes” submitted via Proxy will be counted as present or represented at the Special Meeting for purposes of determining the presence or absence of a quorum.

Required Votes

Only holders of common shares of record at the close of business on the Record Date are entitled to vote at the Special Meeting. For the purpose of voting at the Special Meeting, each common share is entitled to one vote upon all matters to be acted upon at the Special Meeting.

With respect to the matters contained in this proxy statement, each proposal has to be approved by the affirmative vote of a majority of the votes cast by shareholders who voted in respect of such matters, in person or by proxy. That means, only common shares that are voted are taken into account in determining the proportion of votes cast for or against each resolution. Shares that are not voted will not be counted towards the total number of votes cast.

Solicitation of Proxies

We will bear the entire expenses in connection with the solicitation of proxy for the Special Meeting made for and on behalf of us. To the extent legally permissible, if we are successful in our proxy solicitation, we intend to seek reimbursement from the Company of all expenses we incur in connection with the solicitation of proxies for the election of the Nominees to the Board at the Special Meeting. If such reimbursement is approved by the Board, we do not intend to submit the question of such reimbursement to a vote of security holders of the Company.

PROPOSALS OF THIS PROXY STATEMENT

PROPOSAL 1

REMOVAL OF DIRECTORS

Please refer to the section entitled Reasons for Removing the Existing Directors. We firmly believe that restructuring the Board by removing the Existing Directors and replacing with the Nominees we proposed will make a significant contribution to the goals we aim to achieve as set forth in section entitled Reasons for the Solicitation above.

WE STRONGLY URGE YOU TO VOTE “FOR” AND USE THE GOLD PROXY CARD OR GOLD VOTING INSTRUCTION FORM TO AUTHORIZE A PROXY TO VOTE “FOR” THE REMOVAL OF EACH OF DAVID GUOWEI WANG AND SVEN H. BORHO, AND ANY OTHER PERSON OR PERSONS ELECTED OR APPOINTED TO THE BOARD WITHOUT SHAREHOLDERS’ APPROVAL AFTER FEBRUARY 8, 2025 AND UP TO AND INCLUDING THE DATE OF THE SPECIAL MEETING, AS A DIRECTOR OF THE COMPANY AND FROM EACH APPLICABLE COMMITTEE OF THE BOARD.

PROPOSAL 2 

ELECTION OF DIRECTORS

Please refer to the detailed biograph of our Nominees set forth in the section entitled Information of Nominees. We firmly believe that Simon Anderson, Shan Fu, Shuge Jiao, Chiang Li, Yuk Lam Lo, Yumin Qiu, Yu Wang, Rui-Ping Xiao, Andrew Y Yan, and Weidong Yin will be integral to the new Board and will make a significant contribution to the goals we aim to achieve as set forth in section entitled Reasons for the Solicitation above.

WE STRONGLY URGE YOU TO VOTE “FOR” AND USE THE GOLD PROXY CARD OR GOLD VOTING INSTRUCTION FORM TO AUTHORIZE A PROXY TO VOTE “FOR” THE ELECTION OF SIMON ANDERSON, SHAN FU, SHUGE JIAO, CHIANG LI, YUK LAM LO, YUMIN QIU, YU WANG, RUI-PING XIAO, ANDREW Y YAN, AND WEIDONG YIN AS DIRECTORS OF THE COMPANY.