These authors contributed equally: Dina Averbuch, Rafael de la Camara, Jan Styczyński.

Lower Silesia Centre for Oncology, Pulmonology and Hematology in Wroclaw, 53-439, Wroclaw, Poland

Jarosław Dybko & Wojciech Szlasa

Department of Oncology and Hematology, Wroclaw University of Science and Technology, 50-370, Wroclaw, Poland

Jarosław Dybko

Department of Molecular and Cellular Biology, Faculty of Pharmacy, Wroclaw Medical University, Wroclaw, Poland

Wojciech Szlasa

Poznan University of Medical Sciences, Department of Hematology, Poznan, Poland

Lidia Gil

EBMT, Leiden Study Unit, Leiden, The Netherlands

Lotus Wendel, Gloria Tridello & Nina Knelange

University Medical Center Hamburg, Hamburg, Germany

Nicolaus Kröger

Department of Haematology and Blood and Tissue Establishment, University Hospitals Galway, Galway, Ireland

Amjad Hayat

Bone Marrow Transplantation Unit, Department of Internal Medicine, University Hospital of Patras, Patras, Greece

Maria Liga

Radboud University Medical Center, Nijmegen, The Netherlands

Nicole Blijlevens

Bone Marrow Transplantation Program, American University of Beirut, Medical Center, Beirut, Lebanon

Ali Bazarbachi

Hematopoietic Stem Cel Transplant Unit, Institute G. Gaslini, Genova, Italy

Maura Faraci

Hannover Medical School, Department of Haematology, Hemostasis, Oncology and Stem Cell Transplantation Hannover, Hannover, Germany

Arnold Ganser

Department of Internal Medicine II, University Hospital of Würzburg, Würzburg, Germany

Maximilian Steinhardt

Department of Pediatrics, Jena University Hospital, Jena, Germany

Bernd Gruhn

Bone Marrow Transplant Unit, 2nd Department of Internal Medicine Propaedeutic, Attikon University Hospital, Athens, Greece

Maria Stamouli

Hematology Department, Clinica Universidad de Navarra, Pamplona, Spain

Sara Villar

University Hospital, Basel, Switzerland

Jakob Passweg

UZ Brussel – VUB, Brussels, Belgium

Rik Schots

BMT Unit, UOC Ematologia, IRCCS Policlinico San Matteo, Pavia University, Pavia, Italy

Paolo Bernasconi

Rambam Medical Center, Haifa, Israel

Tsila Zuckerman

Infectious Diseases Unit, Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy

Małgorzata Mikulska

Faculty of Medicine, Hebrew University of Jerusalem; Pediatric Infectious Diseases, Hadassah Medical Center, Jerusalem, Israel

Dina Averbuch

Haematology Department, Hospital de la Princesa, Madrid, Spain

Rafael de la Camara

University Hospital, Collegium Medicum UMK, Pediatric Hematology and Oncology, Bydgoszcz, Poland

Jan Styczyński

JD and WS designed the study; LG, NK, AH, ML, NB, AB, MF, AG, MS, BG, MS, SV, JP, RS, PB, TZ and MM enrolled and took care of the patients; LW, GT and NK collected clinical data and performed statistical analyses; JD and WS analyzed data; JD wrote the manuscript; DA, RC and JS revised the manuscript. All authors read and approved the final version of the manuscript.