Study Proves the Immunogenicity and Safety of Co-administration with SINOVAC's WHO Prequalified Varicella and Hepatitis A Vaccines to 1 Year Old

January 6, 2023, Beijing -- Sinovac Biotech Ltd. ("SINOVAC" or the "Company") (NASDAQ: SVA), a leading provider of biopharmaceutical products in China, today announced that a recent study evaluated the immunogenicity and safety of co-administration with two SINOVAC's World Health Organization (WHO) prequalified vaccines to children around 1 year old, which can enhance vaccination efficiency and provide evidence for counties to revise guidelines and optimize immunization programs.

According to the study, recently published by Human Vaccines & Immunotherapeutics, the seropositive rates, antibody levels against varicella-zoster virus (VZV) and hepatitis A virus (HAV), and the geometric mean titers (GMTs) were low before vaccination, indicating most children were susceptible to VZV and HAV, thus it was timely for children around 1 year old to receive both varicella and hepatitis A vaccines. 

As many as 450 participants, aged between 12 to 15 months, were randomly assigned to two groups with a ratio of 1:1. In the co-administration group (Group A), participants received the first dose of hepatitis A vaccine (HepA) co-administrated with one dose of varicella vaccine (VarV) on day 0 and the second dose of HepA on day 180. In the single-dose group (Group B), participants received one dose of VarV on day 0, the first dose of HepA on day 42, and the second dose of HepA on day 222.

After full immunization, the seroconversion rates of anti-VZV antibodies 42 days after vaccination of VarV were 91.79% in Group A and 92.15% in Group B; the GMTs were 11.80 and 12.19, respectively. The seroconversion rates of anti-HAV antibodies 30 days after two-dose vaccination of HepA were 99.48% in Group A and 100.0% in Group B; the geometric mean concentrations reached 9499.11 and 9528.36 mIU/ml, respectively.

The incidence rate of adverse reactions in Group A (9.33%) was lower than Group B (16.22%). While, the only serious adverse event was reported in Group B, which was unrelated to the study vaccine.

In summary, the co-administration of VarV and HepA did not affect the immunogenicity and had good safety profiles. Furthermore, the susceptible population can achieve excellent immune protection after vaccination.

These results suggested that those two vaccines can be administered simultaneously to children around 1 year old. And the vaccination strategy can enhance vaccination efficiency, be time-saving and cost-saving for parents and doctors, and offer pain reduction to children, as well as establish immune protection earlier.

The phase 4 clinical trial adopted SINOVAC’s live attenuated varicella vaccines and inactive hepatitis A vaccine, Healive®, which have been prequalified by the WHO in 2022 and 2017 respectively.

About SINOVAC

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, mumps, 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 by the WHO.

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.

For more information, please see the Company's website at www.sinovac.com.

Contact:

Sinovac Biotech Ltd.

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