BACKGROUND: The available safety data on the use of the messenger RNA-based COVID-19 vaccine BNT162b2 in persons under age 18 are limited to observation periods of up to six months.

METHODS: In a retrospective, cross-sectional study, we evaluated self-reported vaccine tolerability (SRVT) in eleven symptom categories among persons who were under 18 years old when they received at least one dose of the BNT162b2 vaccine in Germany on or after 1 October 2021. Data were collected online from the parents or legal guardians of the vaccinated persons. Individual participation codes enabled authenticated and pseudonymous participation in the survey. In a subgroup, the SRVT of BNT162b2 was compared with that of vaccines against other illnesses than SARS-CoV-2 (e.g., influenza).

RESULTS: Tolerability data were obtained from 3228 persons with a median age of 5.7 years; 49.6% were male. The median period of observation was 524 days. The more commonly reported undesired effects of the vaccine, mainly in older subjects, were local reactions- pain (49.7%), redness (23%)-with less common systemic symptoms including fatigue (20.1%), fever (11.4%), general feeling of illness (8.0%), and headache (6.5%). Compared to vaccines against other illnesses, BNT162b2 was more commonly associated with local and systemic symptoms (gastrointestinal, musculo - skeletal, dermatological, neurological, psychological). 41 (1.3%) of the subjects reported that their SRVT persisted for ≥90 days after vaccination with BNT162b2: these symptoms were mainly psychological (15 subjects), neurological (9 subjects), and dermatological (8 subjects). There were 45 serious adverse events; these were associated with female sex (OR = 4.70, 95% confidence interval [2.17; 10.20]) and with long-term medication use (OR = 4.06 [1.53; 10.79]).

CONCLUSION: Vaccination with BNT162b2 was reportedly well tolerated by more than 98% of the children and adolescents who received it, although symptoms were more common than after vaccination against other illnesses than SARS-CoV-2. The participants in our study may have had a more positive attitude toward vaccination. On the other hand, a selection bias might exist for participants who experienced vaccination side effects.