COVID-19 Pandemic: The Effect on Children

Abstract

Introduction: The emergence of SARS-CoV-2 prompted a global public health response, driven by severe disease and mortality in adult populations. However, the epidemiology, transmission, and immune responses in children remained poorly defined, with limited data on infection burden, transmission, and the impact of vaccination and prior infection on immunity.

Aims: To examine the evolving COVID-19 vaccination pipeline and real-world effectiveness and its impact on children, assess SARS-CoV-2 transmission in educational settings across ancestral and variant periods, characterise paediatric infections and disease severity, and estimate population-level infection and vaccine-induced immunity in Australia.

Results: Rapid vaccine development led to highly immunogenic COVID-19 vaccines with strong protection against severe disease, followed by paediatric studies, with rare adverse events, including myopericarditis, identified. Adult vaccination conferred indirect benefits to children, including reduced reliance on public health restrictions.

Concurrently, observational studies across educational settings showed low secondary attack rates, with staff more frequently identified as index cases; transmission remained modest during Delta and Omicron predominance and was mitigated by layered public health measures and vaccination. Clinical surveillance indicated that most paediatric infections were asymptomatic or mild, with low hospitalisation rates; severe outcomes were uncommon and associated with age and comorbidities. Serial serosurveys demonstrated a transition from minimal seroprevalence in 2020–2021 to >90% by 2022–2023, reflecting widespread infection and hybrid immunity, with increasing antibody concentrations observed with age and repeated exposures.

Conclusion: These findings define the evolving epidemiology and immunity of SARS-CoV-2 in children and provide an evidence base for vaccination policy, maintenance of in-person schooling, and future pandemic preparedness.