An active national survey of the BNT162b2 mRNA COVID-19 vaccine safety in Israeli children

The urgent need for COVID-19 vaccines led to rapid mRNA vaccine development, making safety evaluation essential for current vaccination programs and future mRNA vaccines, particularly in children. To systematically evaluate adverse events (AEs) following two BNT162b2 doses in 5-11-year-old children, including those with comorbidities, a national telephone survey (January-March 2022) was conducted among parents of children who had received the second BNT162b2 dose 21-30 days prior. Children were randomly sampled from the national vaccination registry. For each dose, multivariable logistic regression identified associations between children's characteristics and any AE. Overall, 2,229 children participated (response rate 76.0%); 9.6% had chronic diseases, and 9.2% had pre-existing allergic conditions. Any AE was reported in 58.5%, mainly local (55.7%) or systemic (20.2%); the most common were local pain (54.7%) and fatigue (14.6%), respectively. Most local and systemic AEs resolved within 3 days; medical care was sought for only 1.0% of local and 5.7% of systemic AEs, and no hospitalizations were reported. For both doses, any AE was significantly associated with younger age (first/second doses: aOR = 0.94, 95% CI: 0.90-0.98; aOR = 0.96, 95% CI: 0.92-0.99), female sex (aOR = 1.38, 95% CI: 1.15-1.64 for both), and pre-existing allergic conditions (first/second doses: aOR = 1.99, 95% CI: 1.45-2.74; aOR = 1.71, 95% CI: 1.24-2.35). AE onset, duration, and relative severity were similar regardless of pre-existing allergic status. Exacerbation of chronic and allergic conditions occurred in 4.8% and 2.2%, respectively. BNT162b2 demonstrated a favorable short-term safety profile among children, including those with comorbidities. This study may help inform development and implementation of new mRNA vaccine targets for children.