Assess the efficacy of the candidate oral and aerosolized isotretinoin for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the efficacy of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older. for providing complete protection against COVID-19;Assess the efficacy of the candidate vaccine spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the safety of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine in adults aged 18 years and older.;Assess the safety of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine in combination with oral or aersolized 13 cis retinoic acid in adults aged 18 years and older.

Assess the efficacy of the candidate oral and aerosolized isotretinoin for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the efficacy of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older. for providing complete protection against COVID-19;Assess the efficacy of the candidate vaccine spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the safety of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine in adults aged 18 years and older.;Assess the safety of the candidate spike protein based vaccine such as ChAdOx1 nCoV-19 vaccine in combination with oral or aersolized 13 cis retinoic acid in adults aged 18 years and older.

Assess the efficacy of the candidate oral and aerosolized isotretinoin for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the efficacy of the candidate vaccine ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older. for providing complete protection against COVID-19;Assess the efficacy of the candidate vaccine ChAdOx1 nCoV-19 for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the safety of the candidate vaccine ChAdOx1 nCoV-19 in comparison with oral and aerosolized isotretinoin and vaccine ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older.

Assess the efficacy of the candidate oral and aerosolized isotretinoin for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the efficacy of the candidate vaccine ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older. for providing complete protection against COVID-19;Assess the efficacy of the candidate vaccine ChAdOx1 nCoV-19 for providing complete protection against COVID-19 in adults aged 18 years and older.;Assess the safety of the candidate vaccine ChAdOx1 nCoV-19 in comparison with oral and aerosolized isotretinoin and vaccine ChAdOx1 nCoV-19 combined with oral and aerosolized isotetinoin in adults aged 18 years and older.