Does reactivation of cytomegalovirus contribute to severe COVID-19 disease?

CMV Retinitis in the Context of SARS-CoV-2 Infection: A Case Study and Comprehensive Review of Viral Interactions

PURPOSE

Cytomegalovirus (CMV) retinitis is a sight-threatening condition predominantly affecting immunocompromised individuals, such as those with Human Immunodeficiency Virus (HIV)/Acquired Immunodeficiency Syndrome (AIDS). We aimed to present an observational case report on CMV retinitis following Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and to review the literature on the molecular and cellular changes in CMV and SARS-CoV-2 infections and how they may influence each other. Case Description: A 32-year-old man with a history of AIDS presented with decreased vision and ocular pain exacerbated by movement, beginning a day prior. Ocular examination revealed anterior uveitis, corneal endothelial edema, and retinal necrosis in the left eye. CMV retinitis was diagnosed based on positive serologic testing and a low cluster of differentiation 4 (CD4) count, with concurrent SARS-CoV-2 infection detected. Treatment included valganciclovir and topical agents, with a focus on managing CMV complications. This case highlights the potential role of SARS-CoV-2 in reactivating dormant CMV in severely immunocompromised individuals. We also discuss the implications of this interaction for immunocompromised patients, emphasizing the need for vigilant monitoring and personalized treatment strategies. Conclusions: Our case suggests that SARS-CoV-2 may trigger reactivation of CMV infection, leading to bilateral involvement in patients with low CD4 lymphocyte counts, which can result in severe visual impairment. The review discusses the molecular and cellular interactions between CMV and SARS-CoV-2, as well as risk factors, pathophysiology, and diagnostic methods for CMV retinitis, providing recommendations based on the literature findings.

Prevalence and risk factors of cytomegalovirus reactivation in critically Ill patients with COVID-19 pneumonia

BACKGROUNDS

In critically ill patients with COVID-19, secondary infections are potentially life-threatening complications. This study aimed to determine the prevalence, clinical characteristics, and risk factors of CMV reactivation among critically ill immunocompetent patients with COVID-19 pneumonia.

METHODS

A retrospective cohort study was conducted among adult patients who were admitted to ICU and screened for quantitative real-time PCR for CMV viral load in a tertiary-care hospital during the third wave of the COVID-19 outbreak in Thailand. Cox regression models were used to identify significant risk factors for developing CMV reactivation.

RESULTS

A total of 185 patients were studied; 133 patients (71.9%) in the non-CMV group and 52 patients (28.1%) in the CMV group. Of all, the mean age was 64.7±13.3 years and 101 patients (54.6%) were males. The CMV group had received a significantly higher median cumulative dose of corticosteroids than the non-CMV group (301 vs 177 mg of dexamethasone, p<0.001). Other modalities of treatments for COVID-19 including anti-viral drugs, anti-cytokine drugs and hemoperfusion were not different between the two groups (p>0.05). The 90-day mortality rate for all patients was 29.1%, with a significant difference between the CMV group and the non-CMV group (42.3% vs. 24.1%, p = 0.014). Median length of stay was longer in the CMV group than non-CMV group (43 vs 24 days, p<0.001). The CMV group has detectable CMV DNA load with a median [IQR] of 4,977 [1,365-14,742] IU/mL and 24,570 [3,703-106,642] in plasma and bronchoalveolar fluid, respectively. In multivariate analysis, only a cumulative corticosteroids dose of dexamethasone ≥250 mg (HR = 2.042; 95%CI, 1.130-3.688; p = 0.018) was associated with developing CMV reactivation.

CONCLUSION

In critically ill COVID-19 patients, CMV reactivation is frequent and a high cumulative corticosteroids dose is a significant risk factor for CMV reactivation, which is associated with poor outcomes. Further prospective studies are warranted to determine optimal management.

Clinical features and outcomes of COVID-19 patients with concomitant herpesvirus co-infection or reactivation: A systematic review

Background

Since the first case of COVID-19 was diagnosed in Wuhan, China in late 2019, concomitant infections with Herpesviridae were documented that were presented from simple skin manifestations to severe life-threatening conditions that may lead to mortality. In this systematic review, we have included studies conducted in different parts of the world to find out the association of clinical features and outcomes of COVID-19 infection and concomitant Herpesviridae infection.

Methods

A comprehensive search was conducted in electronic databases including Medline through PubMed, Cochrane database, Scopus and Web of science (core collection). Two review authors independently screened the articles and extracted data. The Risk of bias assessment was done by using RoBANS tool.

Results

A total of 919 studies were retrieved and 19 studies were included having data of 539 patients who were infected with both COVID-19 and Herpesviridae. Herpes Simplex-1, Varicella Zoster, Cytomegalovirus, Epstein-Barr virus and Human Herpes Virus-6 were the detected viruses in the included studies. Cytomegalovirus (CMV) reactivation was the most detected concomitant infection. In case of reactivation with more than one Herpes virus mortality among patients were detected along with single viral infection in some studies. Significant association was noted in dosage and usage of steroid and Herpesviridae reactivation in COVID-19 patients. Blood markers such as D-dimer, CRP along with length of stay in the ICU and usage of invasive mechanical ventilation were found to be the significantly associated markers.

Conclusion

Findings from this study will aid clinicians to assess and treat COVID-19 cases with co-infections.

Immunosenescence and Cytomegalovirus: Exploring Their Connection in the Context of Aging, Health, and Disease

Aging induces numerous physiological alterations, with immunosenescence emerging as a pivotal factor. This phenomenon has attracted both researchers and clinicians, prompting profound questions about its implications for health and disease. Among the contributing factors, one intriguing actor in this complex interplay is human cytomegalovirus (CMV), a member of the herpesvirus family. Latent CMV infection exerts a profound influence on the aging immune system, potentially contributing to age-related diseases. This review delves into the intricate relationship between immunosenescence and CMV, revealing how chronic viral infection impacts the aging immune landscape. We explore the mechanisms through which CMV can impact both the composition and functionality of immune cell populations and induce shifts in inflammatory profiles with aging. Moreover, we examine the potential role of CMV in pathologies such as cardiovascular diseases, cancer, neurodegenerative disorders, COVID-19, and Long COVID. This review underlines the importance of understanding the complex interplay between immunosenescence and CMV. It offers insights into the pathophysiology of aging and age-associated diseases, as well as COVID-19 outcomes among the elderly. By unraveling the connections between immunosenescence and CMV, we gain a deeper understanding of aging's remarkable journey and the profound role that viral infections play in transforming the human immune system.

Potential Signals of COVID-19 as an Effect Modifier of Adverse Drug Reactions

PURPOSE

COVID-19 infection may interact with patients' medical conditions or medications. The objective of this study was to identify potential signals of effect modification of adverse drug reactions by statistical reporting interactions with COVID-19 infection (SRIsCOVID-19) in a large spontaneous reporting database.

METHODS

Data from the US Food and Drug Administration Adverse Event Reporting System through the second quarter of 2020 were used. Three-dimensional disproportionality analyses were conducted to identify drug-event-event (DEE) combinations, for which 1 of the events was COVID-19 infection, that were disproportionately reported. Effect size was quantified by an interaction signal score (INTSS) when COVID-19 was coreported as an adverse event or an indication (INTSSCOVID-19). An SRICOVID-19 exists when the calculated INTSSCOVID-19 is >2. The analyses focused on pandemic-emergent SRIsCOVID-19. Screening for extreme duplication of cases was applied. To assess possible reporting artifacts during the early pandemic as an alternative explanation for pandemic-emergent SRICOVID-19, we repeated the analyses with an additional year of data to gauge temporal stability of our findings.

FINDINGS

When examining DEE interactions, 193 emergent SRIsCOVID-19 were identified, involving 44 drugs and 88 events, in addition to COVID-19 infection. Of the 44 drugs recorded, most were immunosuppressant or modulatory drugs, followed by antivirals. Seven drugs (eg, azithromycin) were identified in emergent SRIsCOVID-19 with preferred terms representing off-label use for prevention or treatment of COVID-19 infection. These drugs were in fact repurposed for COVID-19 treatment, supporting assay sensitivity of our procedure. Infections and infestations were the most frequently observed system organ class, followed by the general disorders and respiratory disorders. The psychiatric system organ class had only a few emergent SRIsCOVID-19 but contained the largest INTSSs. Less commonly reported manifestations of COVID-19 (e.g., skin events) were also identified. After excluding DEE combinations that were highly suggestive of extreme duplication, there remained a more robust set of emergent SRIsCOVID-19, which were supported by biological plausibility considerations. Our findings indicate a relative temporal stability, with >90% of SRIsCOVID-19 persisting after updating the analysis with an additional year of data.

IMPLICATIONS

The signals identified in the analyses could be critical in refining our understanding of the causality of spontaneously reported adverse drug events and thus informing the ongoing care of patients with COVID-19. Our findings also underscore the importance of undetected report duplication as a distorting influence on disproportionality analysis.

Natural killer cells and their exosomes in viral infections and related therapeutic approaches: where are we?

Innate immunity is the first line of the host immune system to fight against infections. Natural killer cells are the innate immunity lymphocytes responsible for fighting against virus-infected and cancerous cells. They have various mechanisms to suppress viral infections. On the other hand, viruses have evolved to utilize different ways to evade NK cell-mediated responses. Viruses can balance the response by regulating the cytokine release pattern and changing the proportion of activating and inhibitory receptors on the surface of NK cells. Exosomes are a subtype of extracellular vesicles that are involved in intercellular communication. Most cell populations can release these nano-sized vesicles, and it was shown that these vesicles produce identical outcomes to the originating cell from which they are released. In recent years, the role of NK cell-derived exosomes in various diseases including viral infections has been highlighted, drawing attention to utilizing the therapeutic potential of these nanoparticles. In this article, the role of NK cells in various viral infections and the mechanisms used by viruses to evade these important immune system cells are initially examined. Subsequently, the role of NK cell exosomes in controlling various viral infections is discussed. Finally, the current position of these cells in the treatment of viral infections and the therapeutic potential of their exosomes are reviewed. Video Abstract.

The relationship between CMV reactivation, anti-cytokine treatment and mortality in critical COVID-19 patients

OBJECTIVE

To examine the use of anti-cytokine treatment in critical COVID-19 patients and their association with the frequency of CMV cases, viral load level, and mortality in these patients.

METHODS

This is a retrospective study. A total of 170 critical and/or intensive care patients with COVID-19 admitted to Hisar Hospital Intercontinental from March 15, 2020, to December 31, 2021 were divided into the use of anti-cytokine treatment group and the no anti-cytokine treatment group. Furthermore, the relationship between CMV reactivation, mortality and anti-cytokine treatment in patients was also examined.

RESULTS

A total of 170 critical COVID-19 patients were included in the study, three of them were excluded. One hundred sixty seven were included in the study of which 38 (22.7%) were found to be CMV DNA positive. As an anti-cytokine treatment, it was observed that tocilizumab was used in 53 patients, anakinra was used in 27 patients, and no anti-cytokine treatment was used in 77 patients. CMV positivity in patients treated with anti-cytokines (31.11%) was found to be significantly higher than in patients who were not treated with it (16.88%) (p:0.033). Furthermore, it was determined that anti-cytokine treatment significantly decreased mortality (p: 0.003) and that there was no significant relationship between CMV reactivation and mortality (p: 0.399).

CONCLUSION

Even though CMV reactivation was high in critical COVID-19 patients who received anti-cytokine treatment, decrease in mortality were observed with early diagnosis and effective treatment. Therefore, CMV infection should be considered in patients receiving immunosuppressive treatment.Clinical Trial Registration: HisarIH-101/NCT05419206.

Accelerated T-Cell Immunosenescence in Cytomegalovirus-Seropositive Individuals After Severe Acute Respiratory Syndrome Coronavirus 2 Infection

Cytomegalovirus (CMV) infection is a major driver of accelerated immunosenescence related to CD28null T cell expansion. CMV infection and these proatherogenic T cells have been independently associated with cardiovascular disease and coronavirus disease 2019 (COVID-19) severity. We investigated the potential contribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to immunosenescence and its relationship with CMV. Innate and adaptive immune subpopulations from individuals with mild or asymptomatic SARS-CoV-2 infection (mCOVID-19) and healthy donors were immunophenotyped. A significant increase in CD28nullCD57+CX3CR1+ T cell percentages (CD4+ [P ≤ .01], CD8+ [P ≤ .01], and TcRγδ (CD4-CD8-) [P ≤ .001]) was found in unnvaccinated CMV-seropositive mCOVID-19 individuals stable up to 12 months after infection. This expansion did not occur in CMV-seronegative mCOVID-19 individuals or in CMV-seropositive individuals infected after SARS-CoV-2 vaccination. There were no significant differences between mCOVID-19 and aortic stenosis groups. Thus, individuals coinfected with SARS-CoV-2 and CMV have accelerated T cell senescence, which might lead to an increased risk of cardiovascular disease.

Targeting CMV Reactivation to Optimize Care for Critically Ill COVID-19 Patients: A Review on the Therapeutic Potential of Antiviral Treatment

Cytomegalovirus (CMV) reactivation has been linked to adverse clinical outcomes in critically ill patients, with emerging evidence suggesting a potential connection with severe COVID-19. Mechanisms driving this association may include primary lung injury, amplification of systemic inflammation, and secondary immunosuppression. Diagnostic challenges in detecting and assessing CMV reactivation necessitate a comprehensive approach to improve accuracy and inform treatment decisions. Currently, there is limited evidence on the efficacy and safety of CMV pharmacotherapy in critically ill COVID-19 patients. Although insights from non-COVID-19 critical illness studies suggest a potential role for antiviral treatment or prophylaxis, the risks and benefits must be carefully balanced in this vulnerable patient population. Understanding the pathophysiological role of CMV in the context of COVID-19 and exploring the advantages of antiviral treatment are crucial for optimizing care in critically ill patients. This review provides a comprehensive synthesis of available evidence, emphasizing the need for additional investigation to establish the role of CMV treatment or prophylaxis in the management of severe COVID-19 and to develop a framework for future research on this topic.

Viral reactivations and co-infections in COVID-19 patients: a systematic review

BACKGROUND

Viral reactivations and co-infections have been reported among COVID-19 patients. However, studies on the clinical outcomes of different viral reactivations and co-infections are currently in limit. Thus, the primary purpose of this review is to perform an overarching investigation on the cases of latent virus reactivation and co-infection in COVID-19 patients to build collective evidence contributing to improving patient health. The aim of the study was to conduct a literature review to compare the patient characteristics and outcomes of reactivations and co-infections of different viruses.

METHODS

Our population of interest included confirmed COVID-19 patients who were diagnosed with a viral infection either concurrently or following their COVID-19 diagnosis. We extracted the relevant literature through a systematic search using the key terms in the online databases including the EMBASE, MEDLINE, Latin American Caribbean Health Sciences Literature (LILACS), from inception onwards up to June 2022. The authors independently extracted data from eligible studies and assessed the risk of bias using the Consensus-based Clinical Case Reporting (CARE) guidelines and the Newcastle-Ottawa Scale (NOS). Main patient characteristics, frequency of each manifestation, and diagnostic criteria used in studies were summarized in tables.

RESULTS

In total, 53 articles were included in this review. We identified 40 reactivation studies, 8 coinfection studies, and 5 studies where concomitant infection in COVID-19 patients was not distinguished as either reactivation or coinfection. Data were extracted for 12 viruses including IAV, IBV, EBV, CMV, VZV, HHV-1, HHV-2, HHV-6, HHV-7, HHV-8, HBV, and Parvovirus B19. EBV, HHV-1, and CMV were most frequently observed within the reactivation cohort, whereas IAV and EBV within the coinfection cohort. In both reactivation and coinfection groups, patients reported cardiovascular disease, diabetes, and immunosuppression as comorbidities, acute kidney injury as complication, and lymphopenia and elevated D-dimer and CRP levels from blood tests. Common pharmaceutical interventions in two groups included steroids and antivirals.

CONCLUSION

Overall, these findings expand our knowledge on the characteristics of COVID-19 patients with viral reactivations and co-infections. Our experience with current review indicates a need for further investigations on virus reactivation and coinfection among COVID-19 patients.

Aged brain and neuroimmune responses to COVID-19: post-acute sequelae and modulatory effects of behavioral and nutritional interventions

Advanced age is one of the significant risk determinants for coronavirus disease 2019 (COVID-19)-related mortality and for long COVID complications. The contributing factors may include the age-related dynamical remodeling of the immune system, known as immunosenescence and chronic low-grade systemic inflammation. Both of these factors may induce an inflammatory milieu in the aged brain and drive the changes in the microenvironment of neurons and microglia, which are characterized by a general condition of chronic inflammation, so-called neuroinflammation. Emerging evidence reveals that the immune privilege in the aging brain may be compromised. Resident brain cells, such as astrocytes, neurons, oligodendrocytes and microglia, but also infiltrating immune cells, such as monocytes, T cells and macrophages participate in the complex intercellular networks and multiple reciprocal interactions. Especially changes in microglia playing a regulatory role in inflammation, contribute to disturbing of the brain homeostasis and to impairments of the neuroimmune responses. Neuroinflammation may trigger structural damage, diminish regeneration, induce neuronal cell death, modulate synaptic remodeling and in this manner negatively interfere with the brain functions.In this review article, we give insights into neuroimmune interactions in the aged brain and highlight the impact of COVID-19 on the functional systems already modulated by immunosenescence and neuroinflammation. We discuss the potential ways of these interactions with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and review proposed neuroimmune mechanisms and biological factors that may contribute to the development of persisting long COVID conditions. We summarize the potential mechanisms responsible for long COVID, including inflammation, autoimmunity, direct virus-mediated cytotoxicity, hypercoagulation, mitochondrial failure, dysbiosis, and the reactivation of other persisting viruses, such as the Cytomegalovirus (CMV). Finally, we discuss the effects of various interventional options that can decrease the propagation of biological, physiological, and psychosocial stressors that are responsible for neuroimmune activation and which may inhibit the triggering of unbalanced inflammatory responses. We highlight the modulatory effects of bioactive nutritional compounds along with the multimodal benefits of behavioral interventions and moderate exercise, which can be applied as postinfectious interventions in order to improve brain health.

COVID-19 infection and vaccines: potential triggers of Herpesviridae reactivation

Since the onset of the COVID-19 outbreak, numerous articles have highlighted a possible link between COVID-19 vaccination or infection and Herpesviridae co-infection or reactivation. The authors conducted an exhaustive literature review on this topic, the results of which are presented individually for each member of the Herpesviridae family: Herpes Simplex Virus (HSV) types-1 (HSV-1) and 2 (HSV-2); Varicella-Zoster Virus (VZV); Epstein-Barr Virus (EBV); Cytomegalovirus (CMV); HHV-6; HHV-7; and HHV-8. These human herpesviruses can serve as prognostic markers for the COVID-19 infection and may even underlie some of the clinical manifestations initially attributed to SARS-CoV-2. In addition to SARS-CoV-2 infection, all corresponding vaccines approved to date in Europe appear capable of inducing herpesvirus reactivation. It is important to consider all viruses of the Herpesviridae family when managing patients infected with or recently vaccinated against COVID-19.

Cytomegalovirus reactivation in patients diagnosed with severe COVID-19: A point prevalence study in a general hospital

OBJECTIVE

To determine the prevalence of CMV reactivation in a population admitted for severe COVID-19 to a general hospital.

METHODS

Point prevalence study in all hospitalized patients with severe COVID-19 (admitted either to general wards or ICU). Determination of the presence of CMV DNA in circulating blood. COVID-19 was confirmed in patients with compatible clinical manifestations, usually with pneumonia and a positive nasopharyngeal PCR test.

RESULTS

We included 140 hospitalized patients with COVID-19 who consented to participate. A total of 16 patients (11.42%), had circulating CMV-DNA in peripheral blood at the time of the study. Patients with positive CMV viral load were mainly ICU patients (11/37 -29,7%) and only 5/103 cases (4,85%) were hospitalized into general wards. The accumulated doses of corticosteroids (prednisone equivalents) in the study day were (median and IQR) 987.50 mg (396.87-2,454.68) and 187.50 mg (75.00-818.12) respectively in CMV positive and negative patients (p < 0.001). A significant proportion of CMV positive patients were discovered because of the study and were clinically unsuspected by their physicians. The coinfected COVID-CMV positive population had a higher risk of accumulated secondary nosocomially-acquired infections and a worse prognosis.

CONCLUSIONS

CMV reactivation should be systematically searched in patients in COVID-19 cases admitted to the ICU.

Human Cytomegalovirus Infection of Epithelial Cells Increases SARS-CoV-2 Superinfection by Upregulating the ACE2 Receptor

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), has caused widespread morbidity and mortality since its onset in late 2019. Here, we demonstrate that prior infection with human cytomegalovirus (HCMV) substantially increases infection with SARS-CoV-2 in vitro. HCMV is a common herpesvirus carried by 40%-100% of the population, which can reactivate in the lung under inflammatory conditions, such as those resulting from SARS-CoV-2 infection. We show in both endothelial and epithelial cell types that HCMV infection upregulates ACE2, the SARS-CoV-2 cell entry receptor. These observations suggest that HCMV reactivation events in the lung of healthy HCMV carriers could exacerbate SARS-CoV-2 infection and subsequent COVID-19 symptoms. This effect could contribute to the disparity of disease severity seen in ethnic minorities and those with lower socioeconomic status, due to their higher CMV seroprevalence. Our results warrant further clinical investigation as to whether HCMV infection influences the pathogenesis of SARS-CoV-2.

Cytomegalovirus Seropositivity in Older Adults Changes the T Cell Repertoire but Does Not Prevent Antibody or Cellular Responses to SARS-CoV-2 Vaccination

Chronic infection with human CMV may contribute to poor vaccine efficacy in older adults. We assessed the effects of CMV serostatus on Ab quantity and quality, as well as cellular memory recall responses, after two and three SARS-CoV-2 mRNA vaccine doses, in older adults in assisted living facilities. CMV serostatus did not affect anti-Spike and anti-receptor-binding domain IgG Ab levels, nor neutralization capacity against wild-type or β variants of SARS-CoV-2 several months after vaccination. CMV seropositivity altered T cell expression of senescence-associated markers and increased effector memory re-expressing CD45RA T cell numbers, as has been previously reported; however, this did not impact Spike-specific CD4+ T cell memory recall responses. CMV-seropositive individuals did not have a higher incidence of COVID-19, although prior infection influenced humoral immunity. Therefore, CMV seropositivity may alter T cell composition but does not impede the durability of humoral protection or cellular memory responses after SARS-CoV-2 mRNA vaccination in older adults.

Multisystem inflammatory syndrome in children (MIS-C) showing disseminated aspergillosis, cytomegalovirus reactivation and persistent SARS-COV-2: Case report with autopsy review

Multisystem inflammatory syndrome in children (MIS-C) is an emerging phenomenon associated with SARS-COV-2 infection (COVID-19) occurring in < 1 % of infected children. MIS-C is characterized by a hyperinflammatory state with excessive cytokine release ('storm') leading to hemodynamic compromise and multiorgan failure, with a death rate of ∼2 %. Autopsy examination can play a particularly important role in helping to understand the pathogenesis of MIS-C. Yet, only five autopsy studies have been reported to date. We report a fatal case of MIS-C involving a previously healthy, 5-year-old Thai boy admitted with MIS-C, one month after exposure to SARS-COV-2. While in intensive care, he was found to have a hypertrophic cardiomyopathy, and despite immunosuppressive treatment for MIS-C, developed shock and died. Multiorgan inflammation was not found at autopsy, implying that the MIS-C had responded to treatment. However, there was disseminated aspergillosis and cytomegalovirus reactivation, attributed to the immunosuppression. SARS-COV-2 virus was also found in multiple organs. To the best of our knowledge, this is the first reported autopsy of an MIS-C patient from Asia, and the first report of aspergillosis in MIS-C. This case underscores that the risks of immunosuppression are also a concern in MIS-C. Although MIS-C is generally considered to be a post-infectious hyperimmune reaction, persistence of SARS-COV-2 is a feature in all autopsies of MIS-C patients reported to date, suggesting a possible role in the pathogenesis, at least in fatal cases.

Roles for Pathogen Interference in Influenza Vaccination, with Implications to Vaccine Effectiveness (VE) and Attribution of Influenza Deaths

Pathogen interference is the ability of one pathogen to alter the course and clinical outcomes of infection by another. With up to 3000 species of human pathogens the potential combinations are vast. These combinations operate within further immune complexity induced by infection with multiple persistent pathogens, and by the role which the human microbiome plays in maintaining health, immune function, and resistance to infection. All the above are further complicated by malnutrition in children and the elderly. Influenza vaccination offers a measure of protection for elderly individuals subsequently infected with influenza. However, all vaccines induce both specific and non-specific effects. The specific effects involve stimulation of humoral and cellular immunity, while the nonspecific effects are far more nuanced including changes in gene expression patterns and production of small RNAs which contribute to pathogen interference. Little is known about the outcomes of vaccinated elderly not subsequently infected with influenza but infected with multiple other non-influenza winter pathogens. In this review we propose that in certain years the specific antigen mix in the seasonal influenza vaccine inadvertently increases the risk of infection from other non-influenza pathogens. The possibility that vaccination could upset the pathogen balance, and that the timing of vaccination relative to the pathogen balance was critical to success, was proposed in 2010 but was seemingly ignored. Persons vaccinated early in the winter are more likely to experience higher pathogen interference. Implications to the estimation of vaccine effectiveness and influenza deaths are discussed.

Hospital-acquired infections in patients hospitalized with COVID-19: First report from Taiwan

BACKGROUND

Coronavirus disease 2019 (COVID-19) inpatients may acquire infections from other pathogens during hospital admission. This is the first research on this subject to be reported from Taiwan.

METHODS

Confirmed COVID-19 inpatients were enrolled in this study from January 1, 2020 to July 31, 2021. Various types of pathogens in COVID-19 inpatients, with hospital-acquired infections, were identified and analyzed. The clinical characteristics of COVID-19 patients with and without hospital-acquired infections were reviewed and compared.

RESULTS

Of the 204 patients included in the study, 32 (15.7%) patients experienced at least one infectious episode. Of 113 recorded episodes of infection, the predominant type was bacterial (88 of 113 infections, 77.9%); the most frequently isolated bacteria were Acinetobacter spp., followed by Stenotrophomonas maltophilia . With regard to viral infections (19 of 113, 16.8%), the Epstein-Barr virus ranked first place among the identified viruses. Four (3.5%) and 2 (1.8%) of 113 infectious episodes were caused by fungi and atypical pathogens. A multivariate analysis revealed that steroid use was an independent factor in hospital-acquired infections (odds ratio [OR], 6.97; 95% confidence interval [CI], 1.15-42.43; p = 0.035). Patients with hospital-acquired infections were associated with increased 28-day and in-hospital mortality (18.8% vs 5.8% and 31.3% and 5.8%; p = 0.023 and <0.01, respectively), and a longer hospital stay (34 vs 19 days; p < 0.001), compared to those without hospital-acquired infections.

CONCLUSION

Our study revealed the unique local epidemiology of hospital-acquired infections among COVID-19 inpatients in Taiwan. These patients were associated with increased mortality and prolonged hospital admissions.

Aging and CMV Infection Affect Pre-existing SARS-CoV-2-Reactive CD8+ T Cells in Unexposed Individuals

Age is a major risk factor for COVID-19 severity, and T cells play a central role in anti-SARS-CoV-2 immunity. Because SARS-CoV-2-cross-reactive T cells have been detected in unexposed individuals, we investigated the age-related differences in pre-existing SARS-CoV-2-reactive T cells. SARS-CoV-2-reactive CD4⁺ T cells from young and elderly individuals were mainly detected in the central memory fraction and exhibited similar functionalities and numbers. Naïve-phenotype SARS-CoV-2-reactive CD8⁺ T cell populations decreased markedly in the elderly, while those with terminally differentiated and senescent phenotypes increased. Furthermore, senescent SARS-CoV-2-reactive CD8⁺ T cell populations were higher in cytomegalovirus seropositive young individuals compared to seronegative ones. Our findings suggest that age-related differences in pre-existing SARS-CoV-2-reactive CD8⁺ T cells may explain the poor outcomes in elderly patients and that cytomegalovirus infection is a potential factor affecting CD8⁺ T cell immunity against SARS-CoV-2. Thus, this study provides insights for developing effective therapeutic and vaccination strategies for the elderly.

Critically ill COVID-19 patients with neutralizing autoantibodies against type I interferons have increased risk of herpesvirus disease

Autoantibodies neutralizing the antiviral action of type I interferons (IFNs) have been associated with predisposition to severe Coronavirus Disease 2019 (COVID-19). Here, we screened for such autoantibodies in 103 critically ill COVID-19 patients in a tertiary intensive care unit (ICU) in Switzerland. Eleven patients (10.7%), but no healthy donors, had neutralizing anti-IFNα or anti-IFNα/anti-IFNω IgG in plasma/serum, but anti-IFN IgM or IgA was rare. One patient had non-neutralizing anti-IFNα IgG. Strikingly, all patients with plasma anti-IFNα IgG also had anti-IFNα IgG in tracheobronchial secretions, identifying these autoantibodies at anatomical sites relevant for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. Longitudinal analyses revealed patient heterogeneity in terms of increasing, decreasing, or stable anti-IFN IgG levels throughout the length of hospitalization. Notably, presence of anti-IFN autoantibodies in this critically ill COVID-19 cohort appeared to predict herpesvirus disease (caused by herpes simplex viruses types 1 and 2 (HSV-1/-2) and/or cytomegalovirus (CMV)), which has been linked to worse clinical outcomes. Indeed, all 7 tested COVID-19 patients with anti-IFN IgG in our cohort (100%) suffered from one or more herpesviruses, and analysis revealed that these patients were more likely to experience CMV than COVID-19 patients without anti-IFN autoantibodies, even when adjusting for age, gender, and systemic steroid treatment (odds ratio (OR) 7.28, 95% confidence interval (CI) 1.14 to 46.31, p = 0.036). As the IFN system deficiency caused by neutralizing anti-IFN autoantibodies likely directly and indirectly exacerbates the likelihood of latent herpesvirus reactivations in critically ill patients, early diagnosis of anti-IFN IgG could be rapidly used to inform risk-group stratification and treatment options.

Trial Registration: ClinicalTrials.gov Identifier: NCT04410263.

Autoantibodies that neutralize the antiviral action of type I interferons are associated with predisposition to severe COVID-19. This study shows that this deficiency in the interferon system is associated with a heightened risk of herpesvirus disease in critically ill patients infected with SARS-CoV-2.

Cytomegalovirus coinfection in patients with severe acute respiratory syndrome coronavirus 2 infection: a systematic review of reported cases

BACKGROUND

Dysfunction of both the innate and the adaptive immune systems is observed in severe coronavirus disease 2019 which, together with administration of immunosuppressive drugs, could lead to cytomegalovirus coinfection or reactivation associated with a poorer outcome. The current study aimed to systematically review the pattern, presentations, clinical course and outcome of patients with severe acute respiratory syndrome coronavirus 2 and cytomegalovirus coinfection.

METHODS

Three online databases, PubMed, Scopus and Web of Science, were searched, and after excluding duplicates and irrelevant reports, eligible articles were identified. Information about patients' age and gender, comorbidities, presentations of coronavirus disease 2019 and cytomegalovirus, treatment courses and outcomes were extracted.

RESULTS

A total of 34 reports with 59 patients with coinfection were considered to be eligible for data extraction. A majority of patients were middle-aged or elderly (84.5%). More than three-fourths (79.2%) had at least one comorbidity. Cytomegalovirus viremia was documented in 43 patients. The most common end organ involved was the gastrointestinal tract in 13 patients (48.1% of 27 patients with end organ involvement), mostly as cytomegalovirus colitis, followed by the respiratory tract in 12 patients. There was a significant association between intubation and fatal outcome (p = .011).

CONCLUSION

We comprehensively reviewed published cases with coronavirus disease 2019 and cytomegalovirus reactivation. The findings may assist in appraising signs and symptoms for early suspicion, detection and treatment in patients with unusual clinical courses or with severe, prolonged or unexplained deterioration of end organ function.

Risk factors for <em>Herpes simplex</em> virus (HSV) and <em>Cytomegalovirus</em> (CMV) infections in critically-ill COVID-19 patients

Background

To assess the prevalence of Herpes simplex and Cytomegalovirus infection in respiratory samples of critically-ill COVID-19 patients, its role in outcome and mortality and the influence of dexamethasone treatment in the early stage of SARS-CoV-2 infection.

Methods

All mechanically ventilated COVID-19 patients treated on ICU between March 2020 and January 2021 were included. Respiratory specimens were tested for Herpes simplex virus (HSV) type 1, 2 and Cytomegalovirus (CMV) by quantitative real-time PCR. Clinical parameters were compared in the cohorts with and without HSV-1- infection.

Results

134 patients with a median age of 72.5 years (73.0% male, n=98) were included. HSV-1 reactivation occurred in 61 patients (45.5%), after median 9 (7-13) days of mechanical ventilation. The main factor for reactivation was length of stay on ICU (24 days vs 13 days, p<0.001) and duration of mechanical ventilation (417 vs 214 hours, p<0.001). Treatment with dexamethasone and a history of immunosuppression did not associate with HSV-infection in the univariate analysis (39 vs 41, p=0.462 and 27.9% vs 23.3%, p=0.561, respectively). Both ICU and hospital mortality were not significantly different in the cohorts with and without HSV-infection (57.4% vs 45.2%, p=0.219).

Conclusions

Our study shows a high prevalence of HSV-infection in critically-ill COVID-19 patients which was unexpectedly higher than the prevalence of CMV-infections and unrelated to dexamethasone treatment. The main risk factors for HSV and CMV in the studied cohorts were the length of ICU stay and duration of mechanical ventilation. Therefore, we recommend routine monitoring of critically ill COVID-19 patients for these viral co-infections and consider treatment in those patients.

Impact of adaptive natural killer cells, KLRC2 genotype and cytomegalovirus reactivation on late mortality in patients with severe COVID-19 lung disease

Objective

SARS-CoV-2 infection results in severe lung disease in up to 50% of hospitalised patients. The aetiopathogenesis in a subset of such patients, who continue to have progressive pulmonary disease following virus clearance, remains unexplored.

Methods

We investigated the role of NKG2C⁺/NKG2A^- adaptive natural killer (ANK) cells, KLRC2 genotype and cytomegalovirus (CMV) reactivation in 22 such patients.

Results

The median duration of virus positivity was 23 days, and the median duration of hospitalisation was 48 days. The overall survival at 60 days in this group was 50%. Older age and comorbidities impacted survival negatively. CMV viraemia was documented in 11 patients, with a survival of 25% vs 80% in those without viraemia with viral load correlating with mortality. Both NK and T cells were markedly depressed in all patients at day 15. However, only persistently low ANK cells at 30 days along with an inversely high NKG2C^-/NKG2A⁺ inhibitory NK cells significantly correlated with high CMV viraemia and mortality, irrespective of KLRC2 genotype. However, day 30 ANK cells were significantly lower in the KLRC2 deletion group. The release of IFN-γ and perforin was severely compromised in all patients at day +15, with significant improvement in the survivors at day +30, but not in those with adverse outcome.

Conclusion

Patients with progressive lung disease even after negative SARS-CoV-2 status, with persistently reduced and functionally compromised ANK cells, are more likely to have CMV reactivation and an adverse outcome, independent of KLRC2 genotype.

Cytomegalovirus blood reactivation in COVID-19 critically ill patients: risk factors and impact on mortality

PURPOSE

Cytomegalovirus (CMV) reactivation in immunocompetent critically ill patients is common and relates to a worsening outcome. In this large observational study, we evaluated the incidence and the risk factors associated with CMV reactivation and its effects on mortality in a large cohort of patients affected by coronavirus disease 2019 (COVID-19) admitted to the intensive care unit (ICU).

METHODS

Consecutive patients with confirmed SARS-CoV-2 infection and acute respiratory distress syndrome admitted to three ICUs from February 2020 to July 2021 were included. The patients were screened at ICU admission and once or twice per week for quantitative CMV-DNAemia in the blood. The risk factors associated with CMV blood reactivation and its association with mortality were estimated by adjusted Cox proportional hazards regression models.

RESULTS

CMV blood reactivation was observed in 88 patients (20.4%) of the 431 patients studied. Simplified Acute Physiology Score (SAPS) II score (HR 1031, 95% CI 1010-1053, p = 0.006), platelet count (HR 0.0996, 95% CI 0.993-0.999, p = 0.004), invasive mechanical ventilation (HR 2611, 95% CI 1223-5571, p = 0.013) and secondary bacterial infection (HR 5041; 95% CI 2852-8911, p < 0.0001) during ICU stay were related to CMV reactivation. 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).

CONCLUSION

The severity of illness and the occurrence of secondary bacterial infections were associated with an increased risk of CMV blood reactivation, which, however, does not seem to influence the outcome of COVID-19 ICU patients independently.

The Contribution of Human Herpes Viruses to γδ T Cell Mobilisation in Co-Infections

γδ T cells are activated in viral, bacterial and parasitic infections. Among viruses that promote γδ T cell mobilisation in humans, herpes viruses (HHVs) occupy a particular place since they infect the majority of the human population and persist indefinitely in the organism in a latent state. Thus, other infections should, in most instances, be considered co-infections, and the reactivation of HHV is a serious confounding factor in attributing γδ T cell alterations to a particular pathogen in human diseases. We review here the literature data on γδ T cell mobilisation in HHV infections and co-infections, and discuss the possible contribution of HHVs to γδ alterations observed in various infectious settings. As multiple infections seemingly mobilise overlapping γδ subsets, we also address the concept of possible cross-protection.

Cytomegalovirus meningoencephalitis in a case of severe COVID-19 Pneumonia. A case report

The use of steroids and other immune modulatory therapies in the treatment of severe COVID-19 pneumonia predisposes patients to the reemergence of opportunistic infections. Cytomegalovirus (CMV) reactivation can be one of them. A 55-year-old gentleman with severe COVID-19 pneumonia and hypoxic respiratory failure who was ventilated and received steroids but no other immunomodulatory drugs; had altered sensorium and multiple episodes of seizures in the later course of his illness. Brain MRI showed leptomeningeal enhancement and encephalopathy changes, electroencephalography (EEG) was suggestive of diffuse encephalopathy and his cerebrospinal fluid (CSF) analysis revealed high Cytomegalovirus PCR DNA titers (103,614). The patient made a complete recovery after treatment with Ganciclovir. Altered sensorium in cases of COVID-19 can be multifactorial. High index of suspicion for reactivation of dormant infections is warranted. CMV meningoencephalitis is one of the differential diagnoses. We believe this is the first case reported of CMV meningoencephalitis in the setting of severe COVID-19 infection.

How Immunosenescence and Inflammaging May Contribute to Hyperinflammatory Syndrome in COVID-19

Aging is characterized by the dynamic remodeling of the immune system designated “immunosenescence,” and is associated with altered hematopoiesis, thymic involution, and lifelong immune stimulation by multitudinous chronic stressors, including the cytomegalovirus (CMV). Such alterations may contribute to a lowered proportion of naïve T-cells and to reduced diversity of the T-cell repertoire. In the peripheral circulation, a shift occurs towards accumulations of T and B-cell populations with memory phenotypes, and to accumulation of putatively senescent and exhausted immune cells. The aging-related accumulations of functionally exhausted memory T lymphocytes, commonly secreting pro-inflammatory cytokines, together with mediators and factors of the innate immune system, are considered to contribute to the low-grade inflammation (inflammaging) often observed in elderly people. These senescent immune cells not only secrete inflammatory mediators, but are also able to negatively modulate their environments. In this review, we give a short summary of the ways that immunosenescence, inflammaging, and CMV infection may cause insufficient immune responses, contribute to the establishment of the hyperinflammatory syndrome and impact the severity of the coronavirus disease 2019 (COVID-19) in elderly people.

Immune Landscape of CMV Infection in Cancer Patients: From "Canonical" Diseases Toward Virus-Elicited Oncomodulation

Human Cytomegalovirus (HCMV) is an immensely pervasive herpesvirus, persistently infecting high percentages of the world population. Despite the apparent robust host immune responses, HCMV is capable of replicating, evading host defenses, and establishing latency throughout life by developing multiple immune-modulatory strategies. HCMV has coexisted with humans mounting various mechanisms to evade immune cells and effectively win the HCMV-immune system battle mainly through maintaining its viral genome, impairing HLA Class I and II molecule expression, evading from natural killer (NK) cell-mediated cytotoxicity, interfering with cellular signaling, inhibiting apoptosis, escaping complement attack, and stimulating immunosuppressive cytokines (immune tolerance). HCMV expresses several gene products that modulate the host immune response and promote modifications in non-coding RNA and regulatory proteins. These changes are linked to several complications, such as immunosenescence and malignant phenotypes leading to immunosuppressive tumor microenvironment (TME) and oncomodulation. Hence, tumor survival is promoted by affecting cellular proliferation and survival, invasion, immune evasion, immunosuppression, and giving rise to angiogenic factors. Viewing HCMV-induced evasion mechanisms will play a principal role in developing novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies. Since tumors acquire immune evasion strategies, anti-tumor immunity could be prominently triggered by multimodal strategies to induce, on one side, immunogenic tumor apoptosis and to actively oppose the immune suppressive microenvironment, on the other side.

Cytomegalovirus as an Uninvited Guest in the Response to Vaccines in People Living with HIV

In stark contrast to the rapid development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an effective human immunodeficiency virus (HIV) vaccine is still lacking. Furthermore, despite virologic suppression and CD4 T-cell count normalization with antiretroviral therapy (ART), people living with HIV (PLWH) still exhibit increased morbidity and mortality compared to the general population. Such differences in health outcomes are related to higher risk behaviors, but also to HIV-related immune activation and viral coinfections. Among these coinfections, cytomegalovirus (CMV) latent infection is a well-known inducer of long-term immune dysregulation. Cytomegalovirus contributes to the persistent immune activation in PLWH receiving ART by directly skewing immune response toward itself, and by increasing immune activation through modification of the gut microbiota and microbial translocation. In addition, through induction of immunosenescence, CMV has been associated with a decreased response to infections and vaccines. This review provides a comprehensive overview of the influence of CMV on the immune system, the mechanisms underlying a reduced response to vaccines, and discuss new therapeutic advances targeting CMV that could be used to improve vaccine response in PLWH.