Reduced immune response to inactivated SARS-CoV-2 vaccine in a cohort of immunocompromised patients in Chile

Inactivated SARS-CoV-2 vaccines have been widely implemented in low- and middle-income countries. However, immunogenicity in immunocompromised patients has not been established. Herein, we aimed to evaluate immune response to CoronaVac vaccine in these patients. This prospective cohort study included 193 participants with five different immunocompromising conditions and 67 controls, receiving two doses of CoronaVac 8-12 weeks before enrollment. The study was conducted between May and August 2021, at Red de Salud UC-CHRISTUS, Chile. Neutralizing antibodies (NAb) positivity, total anti-SARS-CoV-2 IgG antibodies (TAb) concentration, and T cell response were determined. NAb positivity and median neutralizing activity were 83.1% and 51.2% for the control group versus 20.6% (p