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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 global biopharmaceutical company, with a mission of "supply vaccines to eliminate human diseases", the company specializes in the research, development, manufacturing and commercialization of vaccines and related biological products that protect against human infectious diseases.
The company's diversified portfolio includes vaccines for influenza, viral hepatitis, varicella, Hand-Foot-Mouth disease (HFMD), poliomyelitis, pneumococcal disease, etc., of which 3 vaccines have been prequalified by WHO, including inactivated hepatitis A vaccine Healive®, Sabin-strain inactivated polio vaccine (sIPV), and varicella vaccine.
SINOVAC has a leading edge in developing vaccines to combat infectious disease outbreaks and was among the first to initiate R&D during major public health emergencies, including SARS, H5N1, H1N1, and COVID-19. The company developed the world's first inactivated SARS vaccine (Phase I completed), China's first H5N1 influenza vaccine (Paneflu®), the world's first H1N1 influenza vaccine (Panflu.1®), and CoronaVac®, the most widely used inactivated COVID-19 vaccine globally.
Beyond its marketed portfolio, the company is advancing a robust pipeline that includes combination vaccines,recombinant protein vaccines and next-generation platforms such as mRNA technologies and antibodies.
With a long-standing commitment to innovation and global health, SINOVAC is expanding its global footprint by strengthening partnerships with research institutions, international organizations, and local partners. Through broader market presence, technological cooperation, and localized production, the company aims to accelerate vaccine development and supply, enhance regional access to high-quality products, and better address unmet medical needs while improving preparedness for future pandemics.
For more information, please see the Company’s website at www.sinovac.com.