Antiviral agents for prevention or treatment of pathologies caused by alpha- and/or beta-coronaviruses

A method of treating or preventing a pathology caused by alpha- and/or betacoronavirus, which comprises administering to a subject an ester and/or sulfated derivative of hyaluronic acid selected from sulfated hyaluronic acid with an average sulfation degree per disaccharide unit equal to 3 (HAS3) and benzyl ester of hyaluronic acid (HA) with an average carboxyl esterification percentage of 50%, wherein if the derivative of hyaluronic acid is the benzyl ester of HA with an average carboxyl esterification percentage of 50%, it is present within a concentration range of 0.1 to 1% by weight with respect to the total weight of the composition (w/w).