Participants
allergies
SARS-COV-2 INFECTION, ALLERGIES
Community-dwelling adults were eligible to participate in this study if they were Hong Kong residents, aged 18 years or older at enrolment, and had previously received a complete primary series of either BNT162b2 or CoronaVac, with the second dose received at least 180 days earlier. Exclusion criteria included a history of confirmed SARS-CoV-2 infection; a delay of 43 days or more between the first two vaccine doses; contraindication for COVID-19 vaccination, such as severe allergies, use of medication that could impair the immune system in the past 6 months (except topical steroids or short-term oral steroids), use of immunoglobulins, or any blood products within 90 days of enrolment; and being pregnant or breastfeeding, or planning to become pregnant (