Table 1.
Systematic review.
| Author, year Country |
Study design | Herpesvirus | Specimen (detection method) for herpesvirus | COVID-19 Cases |
Non-COVID-19 Controls |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | n Herpesvirus +Casesc | Age Gendera |
Characteristics | SARS-CoV-2 infection (Outcomeb) |
Clinical manifestation of herpesvirus infection | Durationc | Anti-herpesvirus therapy | n | n Herpesvirus + Controls |
Age Gendera |
Characteristics | ||||
| Lehner, 2020 Austria |
Case-control | EBV CMV |
Blood (RT-PCR) |
18 | 14/18 3/18 |
60.5 (52.0-64.5) med (25th-75th percentiles) NR |
COVID-19 patients treated in ICU due to respiratory failure and required invasive ventilation |
Active (NR) |
Biochemical abnormalities that resemble hepatitis and pancreatitis typically caused by herpesviruses like EBV or CMV. A subgroup of COVID-19 patients exhibit a hyperinflammatory pattern similar to sHLH |
NR | NR | 18 | 8/18 1/18 |
58.8 (47.8-72.3) med (25th-75th percentiles) NR |
Consecutive invasively ventilated ICU patients without COVID-19 |
| Majtanova, 2021 Slovakia |
Case-control | HSV1 | NR (RT-PCR) |
18 | 18/18 | 18-29 years - 3 (17%) 30-39 years - 4 (22%) 40-49 years - 4 (22%) ≥ 50 years - 7 (39%) 11 (61%) vs. 7 (39%) |
Herpes simplex keratitis COVID-19 patients | Active (NR) |
Keratitis | NR | NR | 26 | 26/26 | 18-29 years - 4 (15.4%) 30-39 years - 5 (19.2%) 40-49 years - 7 (26.9%) ≥ 50 years - 10 (38.5%) 16 (61.5%) vs. 10 (38.5%) |
Herpes simplex keratitis patients without COVID-19 |
| Naendrup, 2021 Germany |
Case-control | EBV CMV |
Whole blood (RT-PCR) *reactivation defined as DNA levels higher than 1000IU/mL |
117 (reactivation was performed in 55 cases) |
19/55 10/55 |
60 (16-80) EBV reactivation 51 (16-80) CMV reactivation median (min-max) 17 (89.5%) vs. 2 (10.5%) EBV reactivation 9 (90%) vs. 1 (10%) CMV reactivation |
Severe COVID-19 patients treated in ICU without clinical improvement, having persisting fever >2 days and/or persisting laboratory signs of hyperinflammation in the absence of alternative explanations such as pathogens in bronchoalveolar lavages, blood, or urine cultures. |
Active (37% with vs. 50% without EBV reactivation survived ICU, 29% with vs. 42% without rituximab treatment with EBV reactivation survived ICU; 55% with vs. 46% without CMV reactivation survived ICU, 86% with vs. 0% without Ganciclovir treatment with CMV reactivation survived ICU) |
NR | NR | Rituximab for EBV reactivation and Ganciclovir for CMV reactivation | 126 | 18/126 16/126 |
NR NR |
Respondents without COVID-19 |
| Abadias-Granado, 2021 Spain |
Case-control | HHV6 | Blood (Serology) |
16 | 6/16 | NR NR |
COVID-19 patients | Active (NR) |
Skin rash | 4 weeks | NR | 8 | 0/8 | NR NR |
Randomly selected hospitalized patients, of a similar median age, with COVID-19 but without cutaneous manifestations |
| Vigon, 2021 Spain |
Case-control | EBV CMV |
Blood (RT-PCR) |
61 Total 21 mild 17 severe 23 critical COVID-19 |
Total EBV: 10/61 CMV: 12/61 Severe COVID-19 EBV: 2/17 CMV: 4/17 Critical COVID-19 EBV: 8/23 CMV: 8/23 |
42.2 (26-64) mild COVID-19 74.2 (50-90) severe COVID-19 64.1 (42-88) critical COVID-19 med (IQR) 10 (47.6%(vs. 11 (52.4%) mild COVID-19 12 (70.6%) vs. 5 (29.4%) severe COVID-19 14 (60.9%) vs. 9 (39.1%) critical COVID-19 |
SARS-CoV-2 positive patients (performed with RT-qPCR assay in nasopharyngeal smear) older than 18 year with different clinical presentations of COVID-19: mild, severe or critical |
Active (Specific herpesvirus IgG Ab increased progressively in accordance to COVID-19 severity; Relative risk ratio between reactivation of EBV and/or CMV and death during hospitalization due to COVID-19 was 0.8556, although it was not statistically significant) |
NR | NR | NR | 21 | 0/21 0/21 |
NR NR |
Healthy donors (over 18 years and who have never been in contact with SARS-CoV-2 at the time of sampling) with similar age and gender distribution to mild COVID-19 patients. |
| Singh, 2021 USA | Cross-sectional | EBV CMV HSV |
nasopharyngeal, oropharyngeal, and sputum swabs (RT-PCR) |
4259 | 91/4259 3/4259 5/4259 |
45.21±20.43 mean±sd (20-49) min-max 1891(44.4%) vs. 2364 (55.5%) |
COVID-19 patients | Active (NR) |
NR | NR | NR | 46160 | 2627/46160 42/46160 37/46160 |
NR NR |
Respondents without COVID-19 |
| Brinkmann, 2022 Morocco |
Cross-sectional | EBV CMV HSV1 |
NR (RT-PCR, rapid multiplex approach (Sequencing) |
84 | 3/84 0/84 2/84 |
NR NR |
Critically ill COVID-19 patients | Active (NR) |
NR | NR | NR | 66 | 6/66 4/66 2/66 |
NR NR |
Respondents without COVID-19 |
| Kahwagi, 2022 Senegal |
Case-control | EBV VZV HSV HHV7 |
CSF, blood (RT-PCR) |
8 | 8/8 7/8 8/8 8/8 |
NR NR |
COVID-19 patients presenting clinical signs of encephalitis assessed by clinicians and requiring hospitalization. Patients presenting with an identified cause (e.g., Malaria) were excluded from the study. |
Active (NR) |
Encephalitis | NR | NR | 114 | 0/114 0/114 0/114 0/114 |
NR NR |
Patients presenting clinical signs of encephalitis assessed by clinicians and requiring hospitalization without COVID-19 |
| Aragon-Nogales, 2022 UK |
Prospective cohort study | EBV | Blood (PCR) |
181 (27 moderate, 16 severe, 17 critically ill) |
1/17 | For 17 critically ill 4.1 (6 months -15 years) med (min-max) 12 (70.6) vs. 5 (29.4) |
COVID-19 pediatric population with mild, moderate, severe, or critical (critical, if acute respiratory distress syndrome (ARDS), multiorgan failure (MOF), septic shock, or coma occurs) severity of the disease |
Active (NR) |
NR | NR | NR | 516 | NR | 1 day-5years – 207 (40%), 6-12 years – 170 (33%) >12 years - 76 (27%) NR |
COVID-19 negative pediatric population with other viral respiratory diseases |
| Katz, 2022 USA |
Cross-sectional | HSV1 VZV |
Blood (Serology) |
889 | 25/889 16/889 |
0-9 years - 17 (1.9%) 10-17 years - 22 (2.5%) 18-34 years - 355 (39.9) 35-44 years - 99 (11.1%) 45-54 years - 11 (1.2%) 55-64 years - 100 (11.2%) 65-74 years - 109 (12.3%) 75-85 years - 57 (6.5%) >85 years - 57 (6.5%) 380 (42.7%) vs. 509 (57.3%) |
COVID19 out- and in-patients | Active (NR) |
NR | NR | NR | 987849 | 7625/987849 4228/987849 |
0-9 years - 90881 (9.2%) 10-17 years – 66186 (6.7%) 18-34 years - 212388 (21.5%) 35-44 years - 94834 (9.6%) 45-54 years – 106688 (10.8%) 55-64 years - 154104 (15.62%) 65-74 years - 144226 (14.6%) 75-85 years - 83967 (8.5%) >85 years – 34575 (3.5%) 455458 (46.11%) vs. 532391 (53.89%) |
Hospital non-COVID-19 population from the Integrated Data repository (IDR) |
| Romani, 2022 Italy |
Case-control | HHV6 | NR (RT-PCR) |
68 | 1/68 | 6.5 years (0.9-11.5) Med (IQR) 38 (56%) vs. 30 (44%) |
COVID19 pediatric population with mild, moderate or severe disease | Active (NR) |
NR | NR | NR | 16 | 3/16 | 4.4 years (1.7-6.3) 10 (53%) vs. 6 (47%) |
Age matched non-COVID-19 pediatric patients |
| Zhu, 2020 China |
Cross-sectional | HSV CMV EBV |
Nasopharyngeal/ throat swab (RT-PCR) |
257 | 249/257 254/257 205/257 |
51 (2-99) med (min-max) 138 (53.7) vs. 119 (46.3) |
COVID-19 patients | Active (NR) |
NR | From -4 to 0 days from COVID-19 onset | NR | / | / | / | / |
| Wenzel, 2020 Germany |
Case series | EBV HHV6 |
Endomyocardial biopsies (RT-PCR) |
2 | 2/2 1/2 |
Case 1: 39 Case 2:36 2 males |
Patients with myocarditis who recently suffered from COVID-19 | Past (NR) |
NR | 4 weeks | NR | / | / | / | / |
| Zhao, 2020 China |
Cross-sectional | HSV CMV EBV |
Blood (Serology) |
417 | 18/417 0/417 12/417 |
45.2±17.6 mean±sd 198 (47.5) vs. 219 (52.5) |
COVID-19 patients with severe (including severe type implied one of the following conditions: (a) respiratory distress, respiratory rate ≥30 per min; (b) oxygen saturation on quiescent condition ≤ 93%; (c) partial pressure of oxygen in arterial blood/fraction of inspired oxygen (PaO2/FiO2)≤300 mmHg (1 mmHg=0.133 kPa); (iv) and critical type implied one of the following conditions: (a) respiratory failure occurred and mechanical ventilation was required; (b) shock occurred; (c) patients had other organ dysfunction needing intensive care unit monitoring and treatment) and non-severe (including mild type implied the mild clinical symptoms with no abnormal radiological findings, and common type implied fever and respiratory symptoms and pneumonia detected on chest computed tomography) disease | Active (NR) |
NR | NR | NR | / | / | / | / |
| Wu, 2020 China |
Case series | CMV EBV |
nasopharyngeal/ throat swab (RT-PCR) |
74 | 3/74 3/74 |
6.0 (0.10-15.08) med (min-max) 44 (59.5) vs. 30 (40.5) |
Children without comorbidities | Active (NR) |
NR | NR | NR | / | / | / | / |
| Busani, 2020 Italy |
Case series | HSV1 CMV EBV |
Cell free plasma (RT-PCR) |
107 | 2/107 0/107 0/107 |
Case 1 - 66 Case 2 – 49 2 males |
Case 1 - history of hypertension, hypercholesterolemia and depression Case 2 - body-mass index of 32 and no significant medical history |
Active (Complete recovery) |
Ocular manifestations | NR | NR | / | / | / | / |
| Meyer, 2021 France |
Propsective cohort | HSV | blood and lower respiratory tract samples (RT-PCR) |
153 | 40/153 36/146 in blood (19/61 respiratory sample, HSV reactivation in 15/153 in blood and respiratory samples HSV-1 reactivation first in blood in 7/15, in respiratory tract in 6/15 and simultaneously in 2/15 patients) |
60.8 (50-70) med (IQR) 115 (75.2%) vs. 38 (24.8%) |
COVID-19 patients in the ICU with HSV reactivation defined as a HSV-positive PCR in blood or respiratory samples |
Active (After adjustment for mortality risk factors (age, oxygenation and ventilation characteristics, extra-respiratory components of SOFA score and corticosteroid therapy), multivariable Cox regression model showed an increased risk of mortality for HSV1 reactivation) |
NR | The median time from ICU admission to the first HSVpositive sample was 14 days (IQR 9.5–18). |
NR | / | / | / | / |
| Halawi, 2021 Saudi Arabia |
Cross-sectional | CMV HSV1 |
NR (Serology) |
417 | 2/417 123/417 |
< 30 years - 153 (37%) 30-50 years - 234 (56%) > 50 years - 30 (7%) 150 (36%) vs. 267 (64%) |
COVID-19 patients with diarrhea | Active (NR) |
NR | NR | NR | / | / | / | / |
| Paolucci, 2021 Italy |
Cross-sectional | CMV EBV HHV6 |
Serum (Serology) |
104 Total 42 ICU 62 SICU |
0/104 91/104 (40/42 ICU and 51/62 SICU) 0/104 |
ICU patients - 61.5 (55-71.25) SICU patients - 73.5 (57.8-80) med (IQR) 36 (85.7%) vs. 6 (14.3) in ICU 41 (66.1%) vs. 21 (33.9%) in SICU |
COVID-19 patients treated in ICU and SICU | Active (NR) |
NR | NR | NR | / | / | / | / |
| Saade, 2021 France |
Cross-sectional | HSV EBV CMV |
HSV, EBV, CMV=blood; HSV=blood, BAL, skin swabs (RT-PCR) |
100 | 12/100 58/100 19/100 |
59 (53–67) median (min-max) 73 (73%) vs. 23 (23%) |
Severe COVID-19 patients with malignancies and organ recipients | Active (NR) |
Cutaneous-mucous manifestations | NR | Valganciclovir for CMV reactivation, No treatment for EBV reactivation, Acyclovir and Valacyclovir for HSV reactivation | / | / | / | / |
| Xie, 2021 China |
Cross-sectional | EBV | NR (RT-PCR) |
128 | 17/128 | 62 (52-68) med (IQR) 66 (51.6%) vs. 62 (48.4%) |
COVID-19 patients treated in ICU | Active (EBV group had significantly higher 28-day and 14-day mortality than Non-EBV group (p=0.005)) |
NR | NR | NR | / | / | / | / |
| Bašić-Jukić⁎⁎, 2021 Croatia |
Prospective cohort study | VZV EBV CMV |
Serum (RT-PCR) |
104 | 1/104 9/104 27/104 |
56 (45-65) med (IQR) 56 (24-80) med (min-max) 69 (66.3%) vs. 35 (33.7) |
Renal transplant recipients after COVID-19 | Past (NR) |
Herpes Zoster and CMV colitis in one patient each | At the initial evaluation and 6 months after COVID-19 | Foscarnet, Letermovir, Hyperimmune anti-CMV globulins | / | / | / | / |
| Seeßle, 2021 USA |
Case-series | HSV1 | Serum, tracheal secretion, and bronchial lavage (RT-PCR) |
18 available specimens out of 103 COVID-19 patients | 15/18 9/18 in tracheal secretion 6/18 in bronchial lavage |
data for 15 HSV1 positive COVID-19 patients 71 (16) med (IQR) 12 (80%) vs. 3 (20%) |
Patients with laboratory confirmed SARS-CoV-2 infection with an age of 18 years or over invasively ventilated because of severe or critical pneumonia |
Active (Complete recovery) |
NR | 19.5 days mean 18 (12-28) days med (min-max) |
Acyclovir | / | / | / | / |
| Simonnet, 2021 France |
Cross-sectional | EBV CMV HHV6 |
Blood (RT-PCR) |
34 | 28/34 5/34 7/32 |
58 (26–81) med (min-max) 25 (73%) vs. 9 (27%) |
Critically ill COVID-19 patients treated in ICU | Active (No association between ICU mortality and EBV, CMV and HHV-6 reactivation) |
NR | Median delay between ICU admission and initial virus DNA detection: EBV - 4 days (range 0–20) CMV 12 days (range 1–16) HHV6 12 days (range 8–19) |
Ganciclovir or Valganciclovir for CMV reactivation cases | / | / | / | / |
| Chen, 2021 China |
Cross-sectional | EBV CMV |
Blood (Serology) |
67 | 37/67 0/67 |
37 years (IQR 30–52; range 23–81 years) 32 (47.8%) vs. 35 (52.2%) |
COVID-19 hospitalized patients The inclusion criteria in our study were as follows: (1) At least one positive result by real-time quantitative reverse-transcriptase-polymerase-chain reaction (RT-PCR) assay for SARS-CoV-2 when in hospital; (2) Measuring the antibodies against EBV VCA (IgM, IgG), EBV early antigen (EA, IgM) and EBV nuclear antigen (EBNA, IgG); (3) Time of the onset of symptoms to hospital admission less than 2 weeks. Exclusion criteria: (1) In hospital time later than February 29, 2020; (2) Most clinical information were missing. | Active (NR) |
NR | NR | NR | / | / | / | / |
| Gold⁎⁎, 2021 USA |
Cross-sectional | EBV | Blood (Serology, and for seronegative cases RT-PCR also) |
68d 39 LC 29 non-LC |
29/68 Total 26/39 LC patients 3/29 non-LC patients |
21-74 NR |
COVID-19 patients between 21 and 74 years who weren`t pregnant and not vaccinated and/or without symptoms similar to long COVID prior to testing positive for COVID-19. | Past (Long COVID) |
Long-COVID symptoms | At least 4 weeks | NR | / | / | / | / |
| Blumenthal, 2022 South Africa |
Cross-sectional | EBV HHV8 |
Blood (RT-PCR) |
104 | 81/104 21/104 |
53.0 (21.2-85.7) med (min-max) 63 (60.6%) vs. 41 (39.4%) |
Hospitalized COVID-19 patients | Active (NR) |
NR | NR | NR | / | / | / | / |
| Brooks, 2022 USA |
Prospective cohort study | EBV HHV6 |
Plasma (qPCR) |
67 | 15/67 3/67 |
60 (48-66) med (IQR) 39 (58%) vs. 28 (42%) |
COVID-19 adult patients aged ≥18 years | Active | NR | NR | NR | / | / | / | / |
| Huang, 2022 Taiwan |
Cross-sectional | CMV EBV |
Blood (PCR) |
75 | 5/75 12/75 |
NR NR |
COVID-19 patients | Active | NR | NR | NR | / | / | / | / |
| Lino, 2022 Brazil |
Cross-sectional | HHV6 | Nasopharyngeal/ throat swab (RT-PCR) |
60 | 13/60 | 60.1±18.7 mean±sd 37 (61.6%) vs. 23 (38.4%) |
Hospitalized COVID-19 patients with moderate to severe disease | Active (NR) |
NR | NR | NR | / | / | / | / |
| Su, 2022 USA |
Cohort study | EBV CMV |
Blood (RT-PCR) |
209 | 29/209 0/209 |
56±18 mean±sd 18-89 min-max 104 (48.8%) vs. 105 (50.2%) |
Patients with spectrum of acute COVID-19 severities | Active (NR) |
NR | At the clinical diagnosis of COVID-19 | NR | / | / | / | / |
| Carneiro, 2022 Brazil |
Cross-sectional | HSV1 HSV2 VZV CMV HHV6 HHV7 EBV HHV8 |
nasopharyngeal swab (RT-PCR) |
53 | 25/53 23/53 21/53 9/53 9/53 1/53 15/53 4/53 |
63.51±15.68 mean±sd 17-95 min-max 27 (50.9%) vs. 26 (49.1%) |
Patients with COVID-19 diagnosis confirmed by RT-PCR treated in ICUs and with available consent forms signed by the patient or guardian/legal representative. Pregnant women were excluded from the study. |
Active (A statistically significant association was observed between neurological changes and HHV-6 detection (p = 0.034)) |
Central nervous system symptoms | NR | NR | / | / | / | / |
| Gatto⁎⁎, 2022 Italy |
Cross sectional | CMV | whole blood bronchoalveolar lavage (RT-PCR) |
431 | 88/431 in blood 30/88 in bronchoalveolar lavage |
65 (56-72) med (IQR) 323 (74.9%) vs. 108 (25.1%) |
Patients admitted to ICUs with laboratory-confirmed SARS-CoV-2 infection and moderate to severe acute distress respiratory syndrome (ARDS), while Patients with age < 18 years, ICU length of stay (LOS) < 24 h, limitation of care or do not resuscitate order were excluded from the study |
Active (Hospital mortality was higher in patients with (67.0%) than in patients without (24.5%) CMV reactivation but the adjusted analysis did not confirm this association (HR 1141, 95% CI 0.757–1721, p = 0.528)) |
CMV-related pneumonia described as new worsening of pulmonary gas exchange, modification of chest X-ray or computed tomography compatible with new interstitial pneumonia, CMV blood reactivation and no other causes of pneumonia/worsening of pulmonary gas exchange. |
17 (5-26) days in blood med (IQR) |
Ganciclovir for 10 days | / | / | / | / |
| Im, 2022 South Korea |
Cross-sectional and Retrospective cohort study |
EBV | Blood (RT-PCR) |
269f Gr 1 - 212 Gr 2 - 44 Gr 3 - 10 Gr 4 - 2 Gr 5 - 1 Gr 6 - 0 |
45/269 15-29 years - 2/18 30-39 years - 0/36 40-49 years - 2/28 50-59 years - 7/36 60-69 years - 5/45 70-79 years - 15/46 ≥ 80 years - 14/60 Gradus 1 - 30/212 Gradus 2 - 8/44 Gradus 3 - 4/10 Gradus 4 - 2/2 Gradus 5 - 1/1 Gradus 6 - 0/0 |
61.6 mean 15-29 years - 18 (6.7%) 30-39 years - 36 (13.4%) 40-49 years - 28 (10.4%) 50-59 years - 36 (13.4%) 60-69 years - 45 (16.7%) 70-79 years - 46 (17.1%) ≥ 80 years - 60 (22.3%) 109 (40.5%) vs. 160 (59.5%) |
Adult COVID-19 patients (>15 years) classified according to the 6- grade systemf. Patients admitted directly to the intensive care unit (n=29) were not tested and were excluded from the analysis. Also, patients not designated for EBV PCR testing (n=53), as well as, patients who were not tested within 5 days after hospitalization (n=8) were excluded. |
Active (EBV viremia was not associated with COVID-19 progression) |
NR | 2.3 days median |
NR | / | / | / | / |
| Meng, 2022 China |
Cross-sectional | EBV CMV |
Blood (Serology) |
217 | 55/217 Not reported |
NR NR |
COVID‐19 patients defined as the presence of symptoms and positive reverse transcriptase (RT)‐PCR assays were in accordance with Chinese guidelines (sixth version) | Active (Patients with EBV reactivation have statistically nonsignificant higher mortality rate (12 [22%] vs. 18 [11%], p=0.080); As compared to patients with COVID‐19 who did not receive ganciclovir therapy, ganciclovir‐treated patients had improved survival rate (0.98, 95% CI [0.95, 1.00] vs. 0.88, 95% CI [0.81, 0.95], p = .010) |
NR | NR | NR | / | / | / | / |
| Zubchenko⁎⁎, 2022 Ukraine |
Case-control | EBV HHV6 CMV |
saliva, blood, and mucous membrane of the posterior pharyngeal wall (Serology RT-PCR) |
88 | 68/88 (51/68 reactivation) 68/88 (39/68 reactivation) 0/88 |
NR NR |
COVID-19 patients (88) were divided into: 1) post-COVID syndrome and reactivation of herpesviruses (main group) (68) and 2) post-COVID syndrome without detectable DNA of herpesviruses (control group) (20) | Past (NR) |
NR | 1-4 months | NR | / | / | / | / |
a
Gender is reported as n (%) males vs. n (%) females, bOutcomes regarding active herpesvirus infection that refer to death, recovery, complications, etc, as reported in the original article, cDuration between SARS-CoV-2 positive result and herpesvirus clinical manifestation cNumber of Herpesvirus positive cases is reported as number of positive cases out of the total number of cases dThe “long-term long COVID group” was defined as tested positive for COVID-19 at least 90 days prior to being enrolled, and all reported one or more of the long COVID symptoms utilized for this study. The “long-term control group” was defined as tested positive for COVID-19 at least 90 days prior to enrollment, and none reported any of the long COVID symptoms we were assessing. The “short-term long COVID group” was defined as tested positive for COVID-19 21–90 days prior to enrollment, and all reported one or more of the long COVID symptoms utilized for this study. The “short-term control group” was defined as tested positive for COVID-19 21–90 days prior to enrollment, and none reported any of the long COVID symptoms we were assessing. eLong COVID subjects were those that reported one or more of the following un-abating symptoms after recovering from initial SARS-CoV-2 infection: fatigue, insomnia, headaches, myalgia, confusion/brain fog, weakness, rash, pharyngitis, abdominal pain, tinnitus, fever over 101° F, neck lymphadenopathy, or mild-to-moderate hearing loss, fGr 1, Gr 2, Gr 3, Gr 4, and Gr 5 are Gradus 1, 2, 3, 4, 5, and 6 defines as Grade 1, symptomatic but no oxygen therapy required; Grade 2, low-flow nasal cannula oxygenation; Grade 3, high-flow nasal cannula/non-invasive ventilation; Grade 4, mechanical ventilation; Grade 5, extracorporeal membrane oxygenation; Grade 6, death.
Abbreviations: ICU – intensive care unit, SICU – sub-intensive care unit, EBV – Epstein-Barr virus, CMV – cytomegalovirus, sHLH - secondary hemophagocytic lymphohistiocytosis, NR – not reported, CSF – cerebral-spinal fluid, LC patients- Long COVID-19 patients, non-LC – patients without Long COVID-19, USA – United States of America, Ab – antibody, SOFA - Sequential Organ Failure Assessment score.
⁎⁎
Long-COVID or post-COVID symptoms reported