Before a trip, a screening for SARS-CoV-2 infection by RT-PCR is often required and raises the problem of detection of residual viral RNA at distance from the acute infection (post-Covid). At the University Hospital of Geneva, we developed an expertise to distinguish acute from post-Covid infections. Between October and December 2020, 30% of the people tested positive were able to travel because the result corresponded to post-Covid and 65% were put in isolation because of an acute infection with a risk of transmission. To overcome the detection of residual viral RNA by RT-PCR, a rapid antigenic test would be an interesting and less expensive alternative. It could also be performed a few hours before departure.