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Chile Research: CoronaVac® is safe and likely to confer protection against infection caused by SARS-CoV-2 variants in participants aged 3-17 years old
The inactivated COVID-19 vaccine CoronaVac®, innovated and manufactured by Sinovac Biotech LTD. (SINOVAC), has been widely used in Chilean minors since September 2021. Recently, an interim safety and immunogenicity analysis in Chile of an international multicenter, randomized, double-blind, placebo-controlled phase III clinical study was published on the preprint platform MedRxiv to evaluate safety, immunogenicity, and efficacy of CoronaVac® in Chilean children and adolescents aged 3-17 years old.
Between September 2021 and December 2021, a total of 963 Chilean adolescent volunteers aged 3-17 participated in the study. The results of this preliminary analysis show that children and adolescents aged 3-17 are safe after being vaccinated with CoronaVac®, and the humoral immunity and specific T cells induced by the vaccine can protect against new coronavirus infection and severe disease, and neutralize Antibodies recognize Delta and Omicron variants.
Immunogenicity
In children and adolescents aged 3-17, neutralizing antibody titers to COVID-19 increased significantly after two doses of CoronVac®, and antibody levels were higher than in adults1. Among them, the antibody level of children aged 3-11 was slightly higher than that of teenagers aged 12-17. In addition, the seropositivity of both groups reached 100% 4 four weeks after the second dose of CoronaVac®.
两针后四周显著高于免疫前抗体滴度
CoronaVac® immunization induces anti-S1-RBD antibodies with neutralizing capacities in children and adolescents.
Furthermore, the study discovered that two doses of CoronaVac® induce a robust activation and memory population of CD4+ T cells in children and adolescents.
Changes in activation-induced markers (AIMs) expression in CD4+ T cells specific for SARS-CoV-2 after two doses of CoronaVac® in children and adolescents.
Variants
Neutralizing antibodies and specific T cells generated in children and adolescents aged 3-17 after inoculation with two doses of CoronaVac® can recognize the Delta and Omicron variants of the SARS-CoV-2, showing good cross-neutralization. Notably, the immune response to the Omicron variant was stronger than the original strain.
Safety
CoronaVac was well tolerated in 3-17 participants, and the incidence of adverse events after vaccination was low. NO vaccine-related serious adverse events were reported.
The dosage form of CoronaVac used in this study is the same as that of an adult. Previous studies have shown that 3-17-year-olds vaccinated with CoronaVac induces higher levels of neutralizing antibodies than adults and older adults2. Based on a previous real-world study of more than 2 million children in Chile, CoronaVac was 74.5% protective against symptomatic infection in minors 6-16 years old, 91%2 protective against hospitalized cases, and 91% protective against hospitalized cases. The protective effect of ICU hospitalized cases was 93.8%3 .
Up to now, SINOVAC has supplied more than 2.7 billion doses of CoronaVac to the world and has provided protection for minors in 13 countries and regions. There are 250 million doses administered among children aged 3-17 in China have been vaccinated with CoronaVac, SINOVAC will continue to safeguard the health of children and adolescents around the world.
Original Link：
Soto, Jorge A., et al. "An inactivated SARS-CoV-2 vaccine is safe and induces humoral and cellular immunity against virus variants in healthy children and adolescents in Chile." medRxiv (2022). https://www.medrxiv.org/content/10.1101/2022.02.15.22270973v1
Reference：
[1]Kung Y-A, Huang C-G, Huang S-Y, et al. Antibody titers measured by commercial assays are correlated with neutralizing antibody titers calibrated by international standards. medRxiv 2021;2021.07.16.21260618.
[2]Safety, tolerability, and immunogenicity of an inactivated SARS-CoV-2 vaccine (CoronaVac) in healthy children and adolescents: a double-blind, randomised, controlled, phase 1/2 clinical trial.
doi: 10.1016/S1473-3099(21)00319-4
[3]Jara, Alejandro, et al. Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Children and Adolescents: A Large-Scale Observational Study. SSRN（2022）. https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4035405
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, and mumps.
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 was 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.
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