Study design and samples
We did a randomized, open-label, single-centre trial on the safety and immunogenicity of heterologous boost immunization with an orally administered aerosolised Ad5-nCoV after two-dose priming with an inactivated SARS-CoV-2 vaccine in Chinese adults aged 18 years and older (ClinicalTrials.gov number: NCT05043259), which has been reported previously [