Introduction
ADVERSE EVENTS
Intradermal (ID) injection, or the administration of drugs into the dermis, is an alternative method of vaccination to conventional intramuscular (IM) or subcutaneous (SC) routes (Fractional dosing also reduces reactogenicity and systemic adverse events (AEs) due to dose-dependency (Accelerated, dose-sparing approaches towards mass immunization broadens vaccine coverage and population immunity, preventing the spread of SARS-CoV-2 (CoronaVac and ChAdOx1-nCov19 were introduced into Thailand early on during the pandemic; BNT162b2 quickly followed thereafter. This study explored the immunogenicity and reactogenicity of accelerated, fractional, ID dosing regimens of homologous and heterologous COVID-19 vaccines within a Thai population.