Article History
Received: 14 October 2019
Revised: 20 December 2019
Accepted: 6 January 2020
First Online: 22 January 2020
Compliance with ethical standards
: This is a review article for which ethical approval was not required.
: Giovanni Orsolini and Maurizio Rossini received an honorarium from Pfizer in connection with the development of this manuscript. The authors declare they have no conflicts of interest in this work. Ilaria Bertoldi is a Pfizer employee.