SINOVAC Board of Directors Files Investor Presentation Outlining Decisive Actions to Protect Shareholder Interests Highlights bold steps to restore fairness to SINOVAC's common shareholders and deliver long-term value cr

SINOVAC Board of Directors Files Investor Presentation

Outlining Decisive Actions to Protect Shareholder Interests

Highlights bold steps to restore fairness to

SINOVAC's common shareholders and deliver long-term value creation

Urges shareholders to VOTE the WHITE proxy card

"AGAINST" the misguided proposals to remove SINOVAC's Board and appoint the Reconstituted Imposter Former Board Slate

Launches dedicated website: www.VoteSinovac.com

BEIJING, June 24, 2025 - The Board of Directors of SINOVAC Biotech

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

in China, today announced it has filed an investor presentation with the U.S. Securities and Exchange Commission (SEC) as a Form 6-K

and launched a website, www.VoteSinovac.com, with important information and resources in connection with the upcoming Special

Meeting of Shareholders (the "Special Meeting") to be held on Wednesday, July 9, 2025 at 8:00 a.m. China Standard Time (Tuesday,

July 8, 2025 at 8:00 p.m. Atlantic Standard Time).

The presentation outlines the decisive actions taken by the current

SINOVAC Board to restore fairness and deliver value to all SINOVAC shareholders, end years of governance failures committed by the Imposter

Former Board, and set the Company on a path of renewed growth and accountability, while countering the false and destructive claims made

by Advantech/Prime Success ("Advantech/Prime") and Vivo Capital (together known as the "Dissenting Investor Group"),

whose self-serving actions have repeatedly undermined SINOVAC common shareholders' interests.

Key elements of the presentation include:

Refer to slide 12 in the investor presentation referenced herein.

Your Vote is Important

Your vote on or before July 8 will be about the future of SINOVAC,

your receipt of your make-whole dividend payments in the near-term, and the long-term value of your investment.

We urge you to keep SINOVAC's Board in place and vote on the

WHITE proxy card "AGAINST" Proposal 1 to remove the current Board and "AGAINST" Proposal

2 to appoint the Reconstituted Imposter Board Slate. Your vote is critical to ensuring that SINOVAC remains on the path to stability,

growth, and value creation for all shareholders.

DISCARD any items you received asking you to vote for the Reconstituted

Imposter Former Board Slate. If you have already voted for the Reconstituted Imposter Former Board Slate, you can subsequently revoke

it by using the WHITE proxy card or WHITE voting instruction form to vote. Only your latest-dated vote will count!

If you have questions about how your vote can be counted, please contact

our proxy solicitor, Georgeson LLC, toll free at (844) 568-1506 in the U.S and (646) 543-1968 outside the U.S. or via email at SinovacSpecialMeeting@georgeson.com.

Sinovac Biotech Ltd. (SINOVAC) is a China-based biopharmaceutical company

that focuses on the R&D, manufacturing, and commercialization of vaccines that protect against human infectious diseases.

SINOVAC's product portfolio includes vaccines against COVID-19, enterovirus

71 (EV71) infected Hand-Foot-Mouth disease (HFMD), hepatitis A, varicella, influenza, poliomyelitis, pneumococcal disease, etc.

The COVID-19 vaccine, CoronaVac , has been approved

for use in more than 60 countries and regions worldwide. The hepatitis A vaccine, Healive , passed WHO prequalification

requirements in 2017. The EV71 vaccine, Inlive , is an innovative vaccine under "Category 1 Preventative Biological Products"

and commercialized in China in 2016. In 2022, SINOVAC's Sabin-strain inactivated polio vaccine (sIPV) and varicella vaccine were prequalified

SINOVAC was the first company to be granted approval for its H1N1

influenza vaccine Panflu.1 , which has supplied the Chinese government's vaccination campaign and stockpiling program. The Company

is also the only supplier of the H5N1 pandemic influenza vaccine, Panflu , to the Chinese government stockpiling program.

SINOVAC continually dedicates itself to new vaccine R&D, with more

combination vaccine products in its pipeline, and constantly explores global market opportunities. SINOVAC plans to conduct more extensive

and in-depth trade and cooperation with additional countries, and business and industry organizations.

Important Additional Information

and Where to Find It

In connection with SINOVAC's

Special Meeting, SINOVAC has filed with the U.S. Securities and Exchange Commission ("SEC") and mailed to shareholders of

record entitled to vote at the Special Meeting a definitive proxy statement and other documents, including a WHITE proxy card. SHAREHOLDERS

ARE ENCOURAGED TO READ THE PROXY STATEMENT AND ALL OTHER RELEVANT DOCUMENTS WHEN FILED WITH THE SEC AND WHEN THEY BECOME AVAILABLE BECAUSE

THOSE DOCUMENTS WILL CONTAIN IMPORTANT INFORMATION. Investors and other interested parties will be able to obtain the documents free

of charge at the SEC's website, www.sec.gov, or from SINOVAC at its website: https://www.sinovac.com/en-us/Investors/sec_filings.

You may also obtain copies of SINOVAC's definitive proxy statement and other documents, free of charge, by contacting SINOVAC's

Investor Relations Department at ir@sinovac.com.

Safe Harbor Statement

This announcement contains forward-looking statements within the meaning

of Section 21E of the Securities Exchange Act of 1934, as amended, and as defined in the U.S. Private Securities Litigation Reform Act

of 1995. These forward-looking statements can be identified by terminology such as "may," "will," "expect,"

"anticipate," "aim," "estimate," "intend," "plan," "believe,"

"potential," "continue," "is/are likely to" or other similar expressions. Such statements are based

upon current expectations and current market and operating conditions and relate to events that involve known or unknown risks, uncertainties

and other factors, all of which are difficult to predict and many of which are beyond the Company's or Board's control, which

may cause actual results, performance or achievements to differ materially from those in the forward-looking statements. Further information

regarding these and other risks, uncertainties or factors is included in the Company's filings with the U.S. Securities and Exchange

Commission. The Company and Board do not undertake any obligation to update any forward-looking statement as a result of new information,

future events or otherwise, except as required under law.

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