Assess humoral immunogenicity of ChAdOx1 nCoV-19 in people living with HIV;Assess the incidence of adverse events (intervention-related and intervention-unrelated) in HIV-negative adults aged 18-65 year receiving candidate ChAdOx1 nCoV-19 vaccine or placebo (safety);Assess cellular Immunogenicity of ChAdOx1 nCoV-19 in people living with HIV (immunogenicity);Determine if there is a reduction of severe and non-severe COVID-19 disease in HIV-negative adults who receive candidate vaccine ChAdOx1 nCoV-19 compared to placebo recipients (efficacy);Assess the incidence of adverse events (intervention-related and intervention-unrelated) in HIV-positive adults aged 18-65 year receiving candidate ChAdOx1 nCoV-19 vaccine or placebo (safety)

Assess humoral immunogenicity of ChAdOx1 nCoV-19 in people living with HIV;Assess the incidence of adverse events (intervention-related and intervention-unrelated) in HIV-negative adults aged 18-65 year receiving candidate ChAdOx1 nCoV-19 vaccine or placebo (safety);Assess cellular Immunogenicity of ChAdOx1 nCoV-19 in people living with HIV (immunogenicity);Determine if there is a reduction of severe and non-severe COVID-19 disease in HIV-negative adults who receive candidate vaccine ChAdOx1 nCoV-19 compared to placebo recipients (efficacy);Assess the incidence of adverse events (intervention-related and intervention-unrelated) in HIV-positive adults aged 18-65 year receiving candidate ChAdOx1 nCoV-19 vaccine or placebo (safety)