Latest Real-World Data Show Two-shots of CoronaVac® Provides 74.5% Protection Against COVID-19 For Children and Adolescents

· Real-world data show effectiveness of CoronaVac® 74.5% for prevent of COVID-19, 91.0% for hospitalisation and 93.8% for ICU admission in children and adolescents aged 6 to 16 years old

· 95% of individuals who received three doses of CoronaVac® possess neutralising antibodies against Omicron

· To date more than 26.3 million doses of CoronaVac® have been administered in Thailand 

Bangkok, 15 March 2022 - SINOVAC Biotech Ltd. (NASDAQ: SVA) ("SINOVAC" or the "Company") today revealed that a real-world study in Chile found that the effectiveness of CoronaVac® in two million children and adolescents aged 6 to 16 years old with complete primary immunisation was 74.5% for COVID-19, 91.0% for hospitalisation and 93.8% for ICU admission respectively. These findings were announced by Mr. Weining Meng, Vice President of SINOVAC (Hong Kong) Biotech Ltd.) at an exclusive virtual media session with local media in Thailand. 

SINOVAC and its CoronaVac® have been an integral part of the COVID-19 response in Thailand. CoronaVac® is the first imported COVID-19 vaccine in the Kingdom and the second COVID-19 vaccine to gain approval from Thailand’s Ministry of Public Health (MoPH) for emergency use. To date, more than 26.3 million doses of CoronaVac® have been administered in Thailand.


Weining MENG commented, “We are incredibly proud to support Thailand in the fight against COVID-19. With the latest real-world data showing strong evidence that suggested a very good vaccine effectiveness of  CoronaVac® for children, adolescents and adults, we hope to provide reassurance to the people in Thailand that inactivated vaccines remain effective in protecting them against COVID-19."


He continued, “The recent approval from the Thailand Food and Drug Administration for the use of CoronaVac® for children aged six and above is a testament to our commitment to ensure that people of all ages have access to safe and effective vaccines. We continue to support Thailand in accelerating and expanding its vaccine roll-out to children and safeguard them against COVID-19.”


A booster dose of CoronaVac® increases effectiveness against symptomatic COVID-19 and related hospitalisation. A real-world study in Chile on the booster immunisation of CoronaVac® showed that the protect effectiveness increased to 80% 14 days after booster shot of CoronaVac®. Effectiveness against symptomatic infection increased from 56% to 80.2% and prevention of hospitalisation increased from 84% to 88%.    


CoronaVac® offers protection against COVID-19 VOCs including Omicron. A study, published in medRxiv in February 2022, found that those who received a booster dose of CoronaVac® possess neutralising antibodies and T-cells against Delta and Omicron. Results from the study found significant increase in neutralising antibody levels at four weeks after the booster dose.

Data on immunogenicity and safety revealed that CoronaVac® is adaptable for different populations including patients with chronic diseases (i.e., coronary artery disease (CAD), chronic respiratory disease (CRD), diabetes, obesity, cancer and hypertension), the elderly, paediatric, and pregnant and postpartum women.  

 Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Children and Adolescents: A Large-Scale Observational Study. The Lancet. Accessed 15 March 2022.

 Wang K, Jia Z, Bao L et al. Memory B cell repertoire from triple vaccinees against diverse SARS-CoV-2 variants. Nature. 2022. doi:10.1038/s41586-022-04466-x

 Early estimates of the effectiveness of booster shots in Chile. Ministerio de Salud. Accessed 11 October 2021.

Generally, as one of the most widely used COVID-19 vaccines, CoronaVac is proved to be effective and safe in adults. CoronaVac® vaccine showed an adjusted vaccine effectiveness of 65.3% for the prevention of COVID-19, 87.5% for the prevention of hospitalisation, 90.3% for the prevention of ICU admission, and 86.3% for the prevention of COVID-19 related death. Data from multiple clinical trials show that CoronaVac® is associated with minimal incidences of serious adverse events. 

CoronaVac® has been approved for emergency use or conditional marketing use by local drug regulatory authorities and the WHO in more than 50 countries and regions and more than 2.7 billion doses of the vaccine had been delivered worldwide with over 250 million CoronaVac® doses administered in children aged 3 to 17 in China, as of Jan 2022. It is a widely used, well-tolerated, safe and effective vaccine and an important public health measure to fight against the pandemic.


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 COVID-19, enterovirus71 (EV71), hepatitis A and B, seasonal influenza, 23-valent pneumococcal polysaccharide ("PPV"), H5N1 pandemic influenza (avian flu), H1N1 influenza (swine flu), varicella, mumps and poliomyelitis. SINOVAC’s COVID-19 vaccine, CoronaVac, has been granted emergency use approval or conditional marketing authorization in Asia, Latin America, Africa and Middle East countries. Healive, the hepatitis A vaccine manufactured by the Company, has passed the assessment under WHO prequalification procedures in 2017. The EV71 vaccine, an innovative vaccine developed by SINOVAC against hand foot and mouth disease caused by EV71, was commercialized in China in 2016. 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. In 2021, SINOVAC’s Sabin-strain inactivated polio vaccine has approved for registration. The Company is developing several new products including combined vaccines. SINOVAC primarily sells its vaccines in China, while also exploring growth opportunities in international markets. The Company is seeking market authorization of its regular products in countries outside of China. For more information, please see the Company’s website at


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 Early estimates of the effectiveness of booster shots in Chile. Ministerio de Salud. Accessed 11 October 2021.

 World Health Organization. Evidence/Assessment: SINOVAC/CoronaVac COVID-19 Vaccine. Accessed 16 September 2021.