Paleoserology points to Coronavirus as possible causative pathogens of the 'Russian flu'. Issue 7 (5th April 2022) - Ramassy, Lindsay; Oumarou Hama, Hamadou; Costedoat, Caroline; Signoli, Michel; Verna, Emeline; La Scola, Bernard; Aboudharam, Gérard; Barbieri, Rémi; Drancourt, Michel