Funding for this research was provided by:
Received: 2 December 2019
Accepted: 29 August 2020
First Online: 9 September 2020
Ethics approval and consent to participate
: The SHIFT and IBIS studies were approved by Comitato Etico Area Vasta Centro, Azienda Ospedaliera Universitaria Careggi, Firenze, and the Ethics Committees of each study center and were conducted in accordance with the Declaration of Helsinki and the current regulations for observational studies. Selected data from both studies were subsequently pooled and analyzed in the present paper.
: Written informed consent was collected from the parents or legal guardians of every participant in both studies.
: VM has received honoraria by CSL Behring and has taken part to a board sponsored by Takeda. CC, AT and SG declare that they have no competing interests. BM has received honoraria from Takeda and Kedrion. GMB is an employee of CSL Behring.