Participant composition
A total of 39 patients, aged between 5-51 years, received at least one dose of COVID-19 vaccine, including 16 with homologous intramuscular BNT162b2 vaccine (age 13-50 years); 17 with homologous intramuscular CoronaVac vaccine (age 5-51 years). Two elected to receive 3 doses of intradermal CoronaVac, and 4 received 2 doses of intramuscular BNT162b2 and a third dose being intradermal BNT162b2 injection. Patients had a range of IEIs, and their demographics and clinical characteristics are summarized in Table 1. None reported SARS-CoV-2 infection prior to immunization and all available baseline sera tested negative for S-RBD IgG.