Table 2 Summary of detection criteria for each infection category

Parvovirus B19

Not applicable

Not applicable

All studies describing an infection interchangeably with the terms “reactivation” and “coinfection” and the detection criteria are the following:

Seropositive for B19 IgM [54]

EBV

All studies describing an infection as “reactivation” and the detection criteria are the following:

Undetectable viremia from an initial molecular testing followed by the detection of EBV DNA in a subsequent testing [17], or detection of EBV DNA [16, 22, 73, 75, 76, 79, 81] and seropositivity for VCA-IgG and NA-IgG [76, 81], VCA IgG and EA-IgG [73], EA-D IgG and/or with NA IgG [76], VCA-IgG only [81], or VCA-IgG, NA-IgG, EA IgG/IgM [16, 22]

All studies describing an infection as “coinfection” and the detection criteria are the following:

Detection of VCA-IgM [67], and/or with VCA-IgG, EA IgG, NA IgG, positive detection of EBV DNA [55]

All studies describing an infection interchangeably with the terms “reactivation” and “coinfection” and the detection criteria are the following:

Detection of EBV DNA [80]or seropositive for the VCA-IgM, VCA-IgG, NA IgG and/or with EA IgM [54]

CMV

All studies describing an infection as “reactivation” and the detection criteria are the following:

Undetectable viremia from an initial molecular testing followed by the detection of CMV DNA in a subsequent testing [17, 63, 66, 70, 82], or CMV DNA detection and seropositive for either IgG or IgM [41, 51] or both [41], or detection of CMV DNA alone when prior testing for the absence of viremia is not available [15, 23, 42, 44, 60, 62, 81]

All studies describing an infection as “coinfection” and the detection criteria are the following:

Detection of CMV DNA, histological evidence of CMV nuclear inclusion bodies in bone marrow [64]

All studies describing an infection interchangeably with the terms “reactivation” and “coinfection” and the detection criteria are the following:

Detection of CMV DNA [43, 48] or seropositive for CMV IgG and IgM [54]

HBV

All studies describing an infection as “reactivation” and the detection criteria are the following:

Sudden rise in the level of HBV DNA in the subsequent testing [35, 46, 50, 58, 83]or seropositive for HB surface antigen, HB core antigen IgM, HB envelope antibody (not specified) [36]

Not applicable

Not applicable

IAV

Not applicable

All studies describing an infection as “coinfection” and the detection criteria are the following:

Seropositive for IAV IgM [33, 72] or positive detection of IAV RNA [61]

Not applicable

IBV

Not applicable

All studies describing an infection as “coinfection” and the detection criteria are the following:

Seropositive for IBV IgM [33]

Not applicable

VZV

All studies describing an infection as “reactivation” and the detection criteria are the following:

Undetectable viremia from an initial molecular testing followed by the detection of VZV DNA in a subsequent testing [20]

All studies describing an infection as “coinfection” and the detection criteria are the following:

Initial detection of VZV prior to confirmed diagnosis of COVID-19 [59]

All studies describing an infection interchangeably with the terms “reactivation” and “coinfection” and the detection criteria are the following:

Seropositive for VZV IgM [45]

HHV-1

All studies describing an infection as “reactivation” and the detection criteria are the following:

Undetectable viremia from an initial molecular testing followed by the detection of HHV-1 DNA in a subsequent testing [20, 57, 71], detection of HHV-1 DNA [56, 68, 74] and/or seropositive for HHV-1 IgG [60, 69, 77], history of COVID-19 (recovered) prior to HSV-1 detection, or history of COVID-19 [65] and corneal ulcer prior to detection of HSV-1 [19]

Not applicable

Not applicable

HHV-2

All studies describing an infection as “reactivation” and the detection criteria are the following:

Detection of HSV-2 DNA and HSV-2 IgG [49]

Not applicable

Not applicable

HHV-6

All studies describing an infection as “reactivation” and the detection criteria are the following:

Detection of HHV-6 DNA [16, 17, 79] and/or seropositive for HHV-6 IgG [16]

All studies describing an infection as “coinfection” and the detection criteria are the following:

Concomitant detection of HHV-6 DNA with COVID-19 diagnosis [34]

Not applicable

HHV-7

All studies describing an infection as “reactivation” and the detection criteria are the following:

Detection of HHV-7 IgG [16]

Not applicable

Not applicable

HHV-8

All studies describing an infection as “reactivation” and the detection criteria are the following:

Undetectable viremia from an initial molecular testing followed by the detection of HHV-8 DNA in a subsequent testing [71] or seropositive for HHV-8 antibodies (not specified) following a complete recovery from COVID-19 [52]

Not applicable

Not applicable