Immunogenicity and Safety of a SARS-CoV-2 Inactivated Vaccine KCONVAC in Chinese Children: Randomized, Double-blind,...

Area of Science:

• Pediatric Vaccinology
• Immunology
• Infectious Diseases

Background:

• Extending severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination to children is crucial for increasing vaccine uptake and reducing pediatric infections.
• The KCONVAC inactivated vaccine is being evaluated for its safety and immunogenicity in a pediatric cohort.

Purpose of the Study:

• To assess the safety and immunogenicity of the KCONVAC SARS-CoV-2 inactivated vaccine in healthy Chinese children aged 3 to 17 years.
• To evaluate antibody responses, including neutralizing antibodies and receptor binding domain immunoglobulin G (RBD-IgG), following a two-dose vaccination regimen.

Main Methods:

• Two randomized, double-blind, placebo-controlled trials (Phase 1 and Phase 2) enrolled 84 and 480 children, respectively.
• Participants received two doses of KCONVAC or placebo 28 days apart, with adverse events monitored up to Day 28 post-vaccination.
• Humoral immune responses were measured via live virus neutralizing antibody and RBD-IgG assays before vaccination and after the second dose.

Main Results:

• Two KCONVAC doses induced high geometric mean titers for neutralizing antibody (142-150) and RBD-IgG (4154-4253), with 100% seroconversion rates for both antibodies.
• The majority of adverse events were mild to moderate (Grade 1 or 2), primarily injection-site pain, cough, and fever.
• Six serious adverse events, unrelated to vaccination, were reported in the Phase 2 trial.

Conclusions:

• The KCONVAC SARS-CoV-2 vaccine was well-tolerated in children aged 3 to 17 years.
• The vaccine demonstrated robust immunogenicity, eliciting significant antibody responses after a two-dose regimen.
• These findings support the use of KCONVAC for pediatric severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) immunization.