Lancet Respir Med 2022 May 20. Epub 2022 May 20.
National Health Commission (NHC) Key laboratory of Enteric Pathogenic Microbiology, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, China; School of Public Health, Nanjing Medical University, Nanjing, China; Institute of Global Public Health and Emergency Pharmacy, China Pharmaceutical University, Nanjing, China; School of Public Health, Southeast University, Nanjing, China. Electronic address:
Background: Due to waning immunity and protection against infection with SARS-CoV-2, a third dose of a homologous or heterologous COVID-19 vaccine has been proposed by health agencies for individuals who were previously primed with two doses of an inactivated COVID-19 vaccine.
Methods: We did a randomised, open-label, controlled trial to evaluate the safety and immunogenicity of heterologous boost immunisation with an orally administered aerosolised adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) in Chinese adults (≥18 years old) who had previously received two doses of an inactivated SARS-CoV-2 vaccine-Sinovac CoronaVac. Eligible participants were randomly assigned (1:1:1) to receive a heterologous booster vaccination with a low dose (1·0 × 10 viral particles per mL; 0·1 mL; low dose group), or a high dose (1·0 × 10 viral particles per mL; 0·2 mL; high dose group) aerosolised Ad5-nCoV, or a homologous intramuscular vaccination with CoronaVac (0·5 mL). Read More