Table 1 General characteristics of studies 

Year

Frequency

 2020–2021

15

 2017–2019

14

 2014–2016

6

 2010–2013

5

 2020–2021

15

Country of origin

Frequency

 USA

16

 Canada

5

 Germany

3

 China

2

 Netherlands

2

 Norway

2

 Taiwan

2

 South Korea

2

 Australia

1

 Belgium

1

 Denmark

1

 Iran

1

 Spain

1

 UK

1

The phase of transplantation and transplantation type

Frequency

For transplant candidates and donors

1

 Kidney

1

Posttransplant patients

32

 Any solid organ

3

 Heart

3

 All organ recipients except lung recipients

1

 Kidney

12

 Kidney and Liver

1

 Liver

4

 Lung

7

Both post-transplant patients and candidates

4

 Any solid organ

1

 Kidney

2

 Lung

1

For transplant candidates

3

 Kidney

1

 Liver

2