COVID-19 vaccination of children is gaining global support (Committee on Infectious Diseases, 2022), and data on immunogenicity and efficacy/effectiveness are increasing (Walter et al., 2022; Frenck et al., 2021; Han et al., 2021).

Chile has rapidly advanced in a national vaccination campaign for children:

as of February 17, 2022, 79% of children aged 3–17 years have been fully vaccinated (Ministerio de Salud Chile, 2022). Children aged 12–17 years have been vaccinated since June 22, 2021, with the mRNA Pfizer/BioNTech vaccine, followed weeks later by children aged 6–11 years, who received the inactivated Sinovac vaccine. We previously reported a national COVID-19 IgG seropositivity study in adults vaccinated with either vaccine that demonstrated the utility of large cross-sectional immunologic surveys using lateral flow tests (LFTs) (Sauré et al., 2022). In this study, we reported IgG seropositivity in vaccinated and non-vaccinated Chilean school-aged children who received the inactivated vaccine from Sinovac (CoronaVac) or the mRNA vaccine from Pfizer/BioNTech (BNT162b2) within 1–20 weeks before sample collection, or no vaccine. Data on IgG seropositivity among vaccinated children with inactivated as compared with mRNA vaccines are currently