Authors’ contributions
SW is chief investigator; she conceived the study and led the development of the proposal and protocol; she contributed to the development of the statistical design; led the construction of the clinical material; she has drafted the work; she contributes to the acquisition of data. FC is chief investigator; she conceived the study and led the development of the proposal and protocol; she contributed to the development of the statistical design; she led all trial plans; she has drafted the work. CC is investigator; she contributed to the construction of the clinical material; she substantively revised draft; she contributes to the acquisition of data. VD is statistician; he contributed to the development of the statistical design; he participated in the review of the draft; GD is investigator; he contributed to the conception of the study; he contributed to the construction of the clinical material; he participated in the review of the draft; HS is investigator; he contributed to the conception of the study; he contributed to the construction of the clinical material; he participated in the review of the draft; PF is investigator; he contributed to the conception of the study; he contributed to the construction of the clinical material; he participated in the review of the draft; JG is investigator; he contributed to the construction of the clinical material; he contributed to the construction of the clinical material; he participated in the review of the draft; CD is investigator; she contributed to the construction of the clinical material ; she contributed to the construction of the clinical material; she participated in the review of the draft. All authors read and approved the final manuscript. COVCOG group contributed to the conception of the study.