The influence of ABO blood groups on COVID-19 susceptibility and severity: A molecular hypothesis based on carbohydrate-carbohydrate interactions

Investigating ABO Blood Groups and Secretor Status in Relation to SARS-CoV-2 Infection and COVID-19 Severity

The ABO blood groups, Lewis antigens, and secretor systems are important components of transfusion medicine. These interconnected systems have been also shown to be associated with differing susceptibility to bacterial and viral infections, likely as the result of selection over the course of evolution and the constant tug of war between humans and infectious microbes. This comprehensive narrative review aimed to explore the literature and to present the current state of knowledge on reported associations of the ABO, Lewis, and secretor blood groups with SARS-CoV-2 infection and COVID-19 severity. Our main finding was that the A blood group may be associated with increased susceptibility to SARS-CoV-2 infection, and possibly also with increased disease severity and overall mortality. The proposed pathophysiological pathways explaining this potential association include antibody-mediated mechanisms and increased thrombotic risk amongst blood group A individuals, in addition to altered inflammatory cytokine expression profiles. Preliminary evidence does not support the association between ABO blood groups and COVID-19 vaccine response, or the risk of developing long COVID. Even though the emergency state of the pandemic is over, further research is needed especially in this area since tens of millions of people worldwide suffer from lingering COVID-19 symptoms.

Correlation between ABO blood type, susceptibility to SARS-CoV-2 infection and COVID-19 disease severity: A systematic review

OBJECTIVES

To verify the association between the ABO blood type and the risk of SARS-CoV-2 infection and COVID-19 disease severity.

METHODS

This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the 2020 PRISMA Checklist and flow diagram, and articles selected for review were analyzed using the Newcastle-Ottawa Quality Rating Scale. The research question was: "Would the ABO blood group influence the risk of infection and clinical course of patients infected with SARS-CoV-2?", The following databases were used: Embase, PubMed, Virtual Health Library (VHL), Web of Science, ScienceDirect and Scopus. The protocol for this review was registered in the Prospective Register of Systematic Reviews (PROSPERO), number CRD42021245945.

RESULTS

We found 798 articles across PubMed, Embase, Scopus, Web of Science, Science Direct and Virtual Health Library and 54 articles were included in the final analysis. Among 30 studies evaluating the risk of COVID-19 infection, 21 found significant correlations with ABO blood groups, 14 of them revealing an increased risk in blood group A and 15 studies showing a decreased risk in blood group O. Most studies found no significant correlation with disease severity or mortality.

CONCLUSION

The qualitative assessment of available information suggests that blood group A may be a risk factor for COVID-19 infection and that blood group O may have a protective effect. We were unable to determine a clear association between the ABO blood group and mortality. These conclusions are based on highly heterogenous evidence.

EVALUATION OF HUMAN ABO BLOOD GROUPS AND BLOOD COMPONENTS AMONG IRAQI PATIENTS INFECTED WITH CORONAVIRUS DISEASE 2019 (COVID-19)

OBJECTIVE

The aim: To evaluate the differences in blood groups, gender and type of Rh factor, as well as the levels of hemoglobin, white blood cells and platelets among patients infected with COVID-19.

PATIENTS AND METHODS

Materials and methods: A cross-sectional study was performed on 202 patients diagnosed with sever COVID-19 infection who were admitted to the Al-Shefaa center in Al- Hakeem hospital in Al-Najef city.Haematological investigations involved the types of blood groups, Rh factors, haemoglobin (Hb), white blood cells (WBCs), and platelets. In addition, the demographic features including age, gender and presence of any prescribed medications before or at the time of the study were also included.

RESULTS

Results: This study indicated that COVID-19 infected patients with type A blood group are at higher risk of hospitalization than other blood groups, and the majority of these patients were Rh positive. Additionally, WBCs counts indicated that the majority of patients had increased risk of getting infections which demonstrated lower WBC counts than normal. Platelet and Hb levels were normal for the majority of patients.

CONCLUSION

Conclusions: The findings of this study may help in the diagnosis of the pandemic infection with COVID-19, and prediction of the incidence of some complications caused by COVID-19. Further researches are warranted to confirm our findings.

Effects of ABO blood groups and RH-factor on COVID-19 transmission, course and outcome: A review

ABO and Rh blood grouping systems are two of the non-modifiable risk factors that play an important role in the susceptibility, severity and outcomes of COVID-19 infection. This review explores these associations all over the world, in an attempt to conclude a clear idea for future reference in clinical practice. In the present review, a link has been drawn between blood groups and COVID-19 transmission, course and prognosis, as literature suggests that blood group O plays a protective role against the infection, while blood group A exhibits a higher risk of exacerbation. In contrast with Rh negative individuals, Rh positive individuals are prone to more severe infection and complications, despite the fact that the underlying mechanisms of this association remain understudied. Nevertheless, the connection remains subject to controversy; since some studies report doubts about it. Thus, this association requires further investigation.

When the clock ticks wrong with COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the coronavirus family that causes the novel coronavirus disease first diagnosed in 2019 (COVID-19). Although many studies have been carried out in recent months to determine why the disease clinical presentations and outcomes can vary significantly from asymptomatic to severe or lethal, the underlying mechanisms are not fully understood. It is likely that unique individual characteristics can strongly influence the broad disease variability; thus, tailored diagnostic and therapeutic approaches are needed to improve clinical outcomes. The circadian clock is a critical regulatory mechanism orchestrating major physiological and pathological processes. It is generally accepted that more than half of the cell-specific genes in any given organ are under circadian control. Although it is known that a specific role of the circadian clock is to coordinate the immune system's steady-state function and response to infectious threats, the links between the circadian clock and SARS-CoV-2 infection are only now emerging. How inter-individual variability of the circadian profile and its dysregulation may play a role in the differences noted in the COVID-19-related disease presentations, and outcome remains largely underinvestigated. This review summarizes the current evidence on the potential links between circadian clock dysregulation and SARS-CoV-2 infection susceptibility, disease presentation and progression, and clinical outcomes. Further research in this area may contribute towards novel circadian-centred prognostic, diagnostic and therapeutic approaches for COVID-19 in the era of precision health.

Cross-GWAS coherence test at the gene and pathway level

Proximal genetic variants are frequently correlated, implying that the corresponding effect sizes detected by genome-wide association studies (GWAS) are also not independent. Methods already exist to account for this when aggregating effects from a single GWAS across genes or pathways. Here we present a rigorous yet fast method for detecting genes with coherent association signals for two traits, facilitating cross-GWAS analyses. To this end, we devised a new significance test for the covariance of datapoints not drawn independently but with a known inter-sample covariance structure. We show that the distribution of its test statistic is a linear combination of χ2 distributions with positive and negative coefficients. The corresponding cumulative distribution function can be efficiently calculated with Davies’ algorithm at high precision. We apply this general framework to test for dependence between SNP-wise effect sizes of two GWAS at the gene level. We extend this test to detect also gene-wise causal links. We demonstrate the utility of our method by uncovering potential shared genetic links between the severity of COVID-19 and (1) being prescribed class M05B medication (drugs affecting bone structure and mineralization), (2) rheumatoid arthritis, (3) vitamin D (25OHD), and (4) serum calcium concentrations. Our method detects a potential role played by chemokine receptor genes linked to TH1 versus TH2 immune response, a gene related to integrin beta-1 cell surface expression, and other genes potentially impacting the severity of COVID-19. Our approach will be useful for similar analyses involving datapoints with known auto-correlation structures.

Association Between ABO Blood Group System and COVID-19 Severity

OBJECTIVES

A possible association between blood group systems (ABO and Rh) and coronavirus disease 2019 (COVID-19) severity has recently been investigated by various studies with conflicting results. However, due to variations in the prevalence of the ABO and Rh blood groups in different populations, their association with COVID-19 might be varied as well. Therefore, we conducted this study on Libyan participants to further investigate this association and make population-based data available to the worldwide scientific community.

METHODS

In this case-control study, ABO and Rh blood groups in 419 confirmed COVID-19 cases in Zawia, Libya, and 271 healthy controls were compared using descriptive statistics and χ 2 tests.

RESULTS

Blood group A was significantly more prevalent in patients with severe COVID-19 (64/125; 51.2%) than in patients with nonsevere COVID-19 (108/294, 36.7%) (P < .034), whereas the O blood group prevalence was higher in nonsevere COVID-19 cases (131/294, 44.5%) compared with severe cases (43/125, 34.4%) (P < .001).

CONCLUSIONS

The results showed a significant association between blood group A and the severity of COVID-19, whereas patients with blood group O showed a low risk of developing severe COVID-19 infection. No significant association was found between Rh and susceptibility/severity of the disease.

ABO blood group and link to COVID-19: A comprehensive review of the reported associations and their possible underlying mechanisms

ABO blood group is long known to be an influencing factor for the susceptibility to infectious diseases, and many studies have been describing associations between ABO blood types and COVID-19 infection and severity, with conflicting findings. This narrative review aims to summarize the literature regarding associations between the ABO blood group and COVID-19. Blood type O is mostly associated with lower rates of SARS-CoV-2 infection, while blood type A is frequently described as a risk factor. Although results regarding the risk of severe outcomes are more variable, blood type A is the most associated with COVID-19 severity and mortality, while many studies describe O blood type as a protective factor for the disease progression. Furthermore, genetic associations with both the risk of infection and disease severity have been reported for the ABO locus. Some underlying mechanisms have been hypothesized to explain the reported associations, with incipient experimental data. Three major hypotheses emerge: SARS-CoV-2 could carry ABO(H)-like structures in its envelope glycoproteins and would be asymmetrically transmitted due to a protective effect of the ABO antibodies, ABH antigens could facilitate SARS-CoV-2 interaction with the host' cells, and the association of non-O blood types with higher risks of thromboembolic events could confer COVID-19 patients with blood type O a lower risk of severe outcomes. The hypothesized mechanisms would affect distinct aspects of the COVID-19 natural history, with distinct potential implications to the disease transmission and its management.

In Silico Analysis of the Multi-Targeted Mode of Action of Ivermectin and Related Compounds

Some clinical studies have indicated activity of ivermectin, a macrocyclic lactone, against COVID-19, but a biological mechanism initially proposed for this anti-viral effect is not applicable at physiological concentrations. This in silico investigation explores potential modes of action of ivermectin and 14 related compounds, by which the infectivity and morbidity of the SARS-CoV-2 virus may be limited. Binding affinity computations were performed for these agents on several docking sites each for models of (1) the spike glycoprotein of the virus, (2) the CD147 receptor, which has been identified as a secondary attachment point for the virus, and (3) the alpha-7 nicotinic acetylcholine receptor (α7nAChr), an indicated point of viral penetration of neuronal tissue as well as an activation site for the cholinergic anti-inflammatory pathway controlled by the vagus nerve. Binding affinities were calculated for these multiple docking sites and binding modes of each compound. Our results indicate the high affinity of ivermectin, and even higher affinities for some of the other compounds evaluated, for all three of these molecular targets. These results suggest biological mechanisms by which ivermectin may limit the infectivity and morbidity of the SARS-CoV-2 virus and stimulate an α7nAChr-mediated anti-inflammatory pathway that could limit cytokine production by immune cells.

A Deadly Embrace: Hemagglutination Mediated by SARS-CoV-2 Spike Protein at Its 22 N-Glycosylation Sites, Red Blood Cell Surface Sialoglycoproteins, and Antibody

Rouleaux (stacked clumps) of red blood cells (RBCs) observed in the blood of COVID-19 patients in three studies call attention to the properties of several enveloped virus strains dating back to seminal findings of the 1940s. For COVID-19, key such properties are: (1) SARS-CoV-2 binds to RBCs in vitro and also in the blood of COVID-19 patients; (2) although ACE2 is its target for viral fusion and replication, SARS-CoV-2 initially attaches to sialic acid (SA) terminal moieties on host cell membranes via glycans on its spike protein; (3) certain enveloped viruses express hemagglutinin esterase (HE), an enzyme that releases these glycan-mediated bindings to host cells, which is expressed among betacoronaviruses in the common cold strains but not the virulent strains, SARS-CoV, SARS-CoV-2 and MERS. The arrangement and chemical composition of the glycans at the 22 N-glycosylation sites of SARS-CoV-2 spike protein and those at the sialoglycoprotein coating of RBCs allow exploration of specifics as to how virally induced RBC clumping may form. The in vitro and clinical testing of these possibilities can be sharpened by the incorporation of an existing anti-COVID-19 therapeutic that has been found in silico to competitively bind to multiple glycans on SARS-CoV-2 spike protein.

COVID-19, Cation Dysmetabolism, Sialic Acid, CD147, ACE2, Viroporins, Hepcidin and Ferroptosis: A Possible Unifying Hypothesis

Background: iron and calcium dysmetabolism, with hyperferritinemia, hypoferremia, hypocalcemia and anemia have been documented in the majority of COVID-19 patients at later/worse stages. Furthermore, complementary to ACE2, both sialic acid (SA) molecules and CD147 proved relevant host receptors for SARS-CoV-2 entry, which explains the viral attack to multiple types of cells, including erythrocytes, endothelium and neural tissue. Several authors advocated that cell ferroptosis may be the core and final cell degenerative mechanism. Methods: a literature research was performed in several scientific search engines, such as PubMed Central, Cochrane Library, Chemical Abstract Service. More than 500 articles were retrieved until mid-December 2021, to highlight the available evidence about the investigated issues. Results: based on COVID-19 literature data, we have highlighted a few pathophysiological mechanisms, associated with virus-based cation dysmetabolism, multi-organ attack, mitochondria degeneration and ferroptosis. Our suggested elucidated pathological sequence is: a) spike protein subunit S1 docking with sialylated membrane glycoproteins/receptors (ACE2, CD147), and S2 subunit fusion with the lipid layer; b) cell membrane morpho-functional changes due to the consequent electro-chemical variations and viroporin action, which induce an altered ion channel function and intracellular cation accumulation; c) additional intracellular iron concentration due to a deregulated hepcidin-ferroportin axis, with higher hepcidin levels. Viral invasion may also affect erythrocytes/erythroid precursors, endothelial cells and macrophages, through SA and CD147 receptors, with relative hemoglobin and iron/calcium dysmetabolism. AB0 blood group, hemochromatosis, or environmental elements may represent possible factors which affect individual susceptibility to COVID-19.     Conclusions: our literature analysis confirms the combined role of SA molecules, ACE2, CD147, viroporins and hepcidin in determining the cation dysmetabolism and final ferroptosis in the cells infected by SARS-CoV-2. The altered ion channels and electrochemical gradients of the cell membrane have a pivotal role in the virus entry and cell dysmetabolism, with subsequent multi-organ immune-inflammatory degeneration and erythrocyte/hemoglobin alterations.

COVID-19, Cation Dysmetabolism, Sialic Acid, CD147, ACE2, Viroporins, Hepcidin and Ferroptosis: A Possible Unifying Hypothesis

Background: iron and calcium dysmetabolism, with hyperferritinemia, hypoferremia, hypocalcemia and anemia have been documented in the majority of COVID-19 patients at later/worse stages. Furthermore, complementary to ACE2, both sialic acid (SA) molecules and CD147 proved relevant host receptors for SARS-CoV-2 entry, which explains the viral attack to multiple types of cells, including erythrocytes, endothelium and neural tissue. Several authors advocated that cell ferroptosis may be the core and final cell degenerative mechanism. Methods: a literature research was performed in several scientific search engines, such as PubMed Central, Cochrane Library, Chemical Abstract Service. More than 500 articles were retrieved until mid-December 2021, to highlight the available evidence about the investigated issues. Results: based on COVID-19 literature data, we have highlighted a few pathophysiological mechanisms, associated with virus-based cation dysmetabolism, multi-organ attack, mitochondria degeneration and ferroptosis. Our suggested elucidated pathological sequence is: a) spike protein subunit S1 docking with sialylated membrane glycoproteins/receptors (ACE2, CD147), and S2 subunit fusion with the lipid layer; b) cell membrane morpho-functional changes due to the consequent electro-chemical variations and viroporin action, which induce an altered ion channel function and intracellular cation accumulation; c) additional intracellular iron concentration due to a deregulated hepcidin-ferroportin axis, with higher hepcidin levels. Viral invasion may also affect erythrocytes/erythroid precursors, endothelial cells and macrophages, through SA and CD147 receptors, with relative hemoglobin and iron/calcium dysmetabolism. AB0 blood group, hemochromatosis, or environmental elements may represent possible factors which affect individual susceptibility to COVID-19.     Conclusions: our literature analysis confirms the combined role of SA molecules, ACE2, CD147, viroporins and hepcidin in determining the cation dysmetabolism and final ferroptosis in the cells infected by SARS-CoV-2. The altered ion channels and electrochemical gradients of the cell membrane have a pivotal role in the virus entry and cell dysmetabolism, with subsequent multi-organ immune-inflammatory degeneration and erythrocyte/hemoglobin alterations.

Impact of ABO and Rhesus blood groups on COVID-19 susceptibility and severity: A case-control study

Early evidence from China suggested that blood groups may be involved in susceptibility to COVID‐19. Several subsequent studies reported controversial results. We conducted a retrospective matched case‐control study that aims to investigate the association between blood groups and the risk and/or severity of COVID‐19. We compared the blood groups distribution of 474 patients admitted to the hospital for COVID‐19 between March 2020 and March 2021, to that of a positive control group of outpatients infected with COVID‐19 and matched them for sex and age, as well as to the distribution in the general population. Three hundred and eighteen HC+ pairs with available blood group information were matched. The proportion of group A Rh+ in hospitalized patients (HC+) was 39.9% (CI 35.2%–44.7%), compared to 44.8% (CI 39.8%–49.9%) and 32.3% in the positive outpatient controls (C+) and the general population (C−), respectively. Both COVID‐19‐positive groups (HC+ and C+) had significantly higher proportions of group A Rh+ compared to the general population (p = 0.0019 and p < 0.001, respectively), indicating that group A Rh+ increases susceptibility to COVID‐19. Although blood group A Rh+ was more frequent in the outpatients C+ compared to the hospitalized group HC+, the association did not reach statistical significance, indicating that blood group A Rh+ is not associated with severity. There was no significant relationship between COVID‐19 and other blood groups. Our findings indicate that blood group A Rh+ increases the susceptibility for COVID‐19 but is not associated with higher disease severity.

Genome-wide Association Study of Estradiol Levels and the Causal Effect of Estradiol on Bone Mineral Density

CONTEXT

Estradiol is the primary female sex hormone and plays an important role for skeletal health in both sexes. Several enzymes are involved in estradiol metabolism, but few genome-wide association studies (GWAS) have been performed to characterize the genetic contribution to variation in estrogen levels.

OBJECTIVE

Identify genetic loci affecting estradiol levels and estimate causal effect of estradiol on bone mineral density (BMD).

DESIGN

We performed GWAS for estradiol in males (n = 147 690) and females (n = 163 985) from UK Biobank. Estradiol was analyzed as a binary phenotype above/below detection limit (175 pmol/L). We further estimated the causal effect of estradiol on BMD using Mendelian randomization.

RESULTS

We identified 14 independent loci associated (P < 5 × 10-8) with estradiol levels in males, of which 1 (CYP3A7) was genome-wide and 7 nominally (P < 0.05) significant in females. In addition, 1 female-specific locus was identified. Most loci contain functionally relevant genes that have not been discussed in relation to estradiol levels in previous GWAS (eg, SRD5A2, which encodes a steroid 5-alpha reductase that is involved in processing androgens, and UGT3A1 and UGT2B7, which encode enzymes likely to be involved in estradiol elimination). The allele that tags the O blood group at the ABO locus was associated with higher estradiol levels. We identified a causal effect of high estradiol levels on increased BMD in both males (P = 1.58 × 10-11) and females (P = 7.48 × 10-6).

CONCLUSION

Our findings further support the importance of the body's own estrogen to maintain skeletal health in males and in females.

A comprehensive review of COVID-19 biology, diagnostics, therapeutics, and disease impacting the central nervous system

The ongoing COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly transmissible disease. SARS-CoV-2 is estimated to have infected over 153 million people and to have caused over 3.2 million global deaths since its emergence in December 2019. SARS-CoV-2 is the seventh coronavirus known to infect humans, and like other coronaviruses, SARS-CoV-2 infection is characterized by a variety of symptoms including general flu-like symptoms such as a fever, sore throat, fatigue, and shortness of breath. Severe cases often display signs of pneumonia, lymphopenia, acute kidney injury, cardiac injury, cytokine storms, lung damage, acute respiratory distress syndrome (ARDS), multiple organ failure, sepsis, and death. There is evidence that around 30% of COVID-19 cases have central nervous system (CNS) or peripheral nervous system (PNS) symptoms along with or in the absence of the previously mentioned symptoms. In cases of CNS/PNS impairments, patients display dizziness, ataxia, seizure, nerve pain, and loss of taste and/or smell. This review highlights the neurological implications of SARS-CoV-2 and provides a comprehensive summary of the research done on SARS-CoV-2 pathology, diagnosis, therapeutics, and vaccines up to May 5.

Catch Me if You Can: Superspreading of COVID-19

While significant insights have been gained concerning COVID-19, superspreading of coronaviruses remains a mystery. The vast majority of cases have been linked to a relatively small portion of infected individuals. Yet, the genetic sequence of the virus, severity of disease, and underlying host parameters, such as age, sex, and health conditions, are not clearly driving the superspreading phenomenon. In this commentary we discuss what is known and what is not known about coronavirus superspreader transmission and explore whether characteristics of the virion, the donor, or the environment contribute to this phenomenon.

Host polymorphisms and COVID-19 infection

Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus, severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). There is growing evidence that host genetics play an important role in COVID-19 severity. Based on current knowledge about the human protein machinery for SARS-CoV-2 entry, the host innate immune response, and virus-host interactions, the potential effects of human genetic polymorphisms, which may contribute to clinical differences in SARS-CoV-2 pathogenesis, may help to determine the individual risk for COVID-19 infection and outcome.

Association between blood groups and COVID-19 outcome in Iranian patients

Aim: Many factors have been speculated to explain the COVID-19 complex clinical phenotype. Due to the inconsistent data published on blood groups and COVID-19, we conducted a study on Iranian patients to further assess this association. Materials & methods: This retrospective study was conducted on data collected from confirmed COVID-19 hospitalized patients during March and December 2020 in a referral hospital for COVID-19, 5 Azar Hospital, Gorgan, north of Iran. A total of 1554 confirmed COVID-19 cases were enrolled in the study with blood group (ABO and Rh), demographic, and clinical data available. Results: Of 1554 patients, 1267 and 287 cases had recovered and deceased (due to COVID-19) outcomes, respectively. Most of the cases had O+ (29.6%), the least number had AB- (0.5%), and most of the deceased cases had O+ blood types (31.4%). Logistic regression analysis revealed that groups A- and B- had higher and groups B+, AB+, O+ and O- had lower odds of death than the A+ group. Conclusion: This study indicates that blood types may be related to the clinical outcome of COVID-19. Further studies with a large cohort for multiple people are required to validate this association.

The trans-omics landscape of COVID-19

The outbreak of coronavirus disease 2019 (COVID-19) is a global health emergency. Various omics results have been reported for COVID-19, but the molecular hallmarks of COVID-19, especially in those patients without comorbidities, have not been fully investigated. Here we collect blood samples from 231 COVID-19 patients, prefiltered to exclude those with selected comorbidities, yet with symptoms ranging from asymptomatic to critically ill. Using integrative analysis of genomic, transcriptomic, proteomic, metabolomic and lipidomic profiles, we report a trans-omics landscape for COVID-19. Our analyses find neutrophils heterogeneity between asymptomatic and critically ill patients. Meanwhile, neutrophils over-activation, arginine depletion and tryptophan metabolites accumulation correlate with T cell dysfunction in critical patients. Our multi-omics data and characterization of peripheral blood from COVID-19 patients may thus help provide clues regarding pathophysiology of and potential therapeutic strategies for COVID-19.

ABO phenotype and SARS-CoV-2 infection: Is there any correlation?

COVID-19 is the currently evolving viral disease worldwide. It mainly targets the respiratory organs, tissues and causes illness. A plethora of studies has been performing to bring proper treatment and prevent people from the infection. Likewise, susceptibility to some infectious diseases has been associated with blood group phenotypes. The co-relationship of blood group with the occurrence of SARS-CoV-2 infection and death has been examined in numerous studies. This review explained the described studies regarding the correlation of blood group and the other essential factors with COVID-19.

COVID-19 and syndemic challenges in 'Battling the Big Three': HIV, TB and malaria

Indirect effects of the COVID-19 pandemic have the potential to seriously undermine the health system in sub-Saharan Africa with an increase in the incidences of malaria, tuberculosis (TB) and HIV infections. Based on current evidence in the African region the collateral impact of COVID-19 on the "big three diseases" shall be addressed in the following.

Association between ABO blood types and coronavirus disease 2019 (COVID-19), genetic associations, and underlying molecular mechanisms: a literature review of 23 studies

An association of various blood types and the 2019 novel coronavirus disease (COVID-19) has been found in a number of publications. The aim of this literature review is to summarize key findings related to ABO blood types and COVID-19 infection rate, symptom presentation, and outcome. Summarized findings include associations between ABO blood type and higher infection susceptibility, intubation duration, and severe outcomes, including death. The literature suggests that blood type O may serve as a protective factor, as individuals with blood type O are found COVID-19 positive at far lower rates. This could suggest that blood type O individuals are less susceptible to infection, or that they are asymptomatic at higher rates and therefore do not seek out testing. We also discuss genetic associations and potential molecular mechanisms that drive the relationship between blood type and COVID-19. Studies have found a strong association between a locus on a specific gene cluster on chromosome three (chr3p21.31) and outcome severity, such as respiratory failure. Cellular models have suggested an explanation for blood type modulation of infection, evidencing that spike protein/Angiotensin-converting enzyme 2 (ACE2)-dependent adhesion to ACE2-expressing cell lines was specifically inhibited by monoclonal or natural human anti-A antibodies, so individuals with non-A blood types, specifically O, or B blood types, which produce anti-A antibodies, may be less susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection due to the inhibitory effects of anti-A antibodies.

COVID-19: Understanding Inter-Individual Variability and Implications for Precision Medicine

Coronavirus disease 2019 (COVID-19) is characterized by heterogeneity in susceptibility to the disease and severity of illness. Understanding inter-individual variation has important implications for not only allocation of resources but also targeting patients for escalation of care, inclusion in clinical trials, and individualized medical therapy including vaccination. In addition to geographic location and social vulnerability, there are clear biological differences such as age, sex, race, presence of comorbidities, underlying genetic variation, and differential immune response that contribute to variability in disease manifestation. These differences may have implications for precision medicine. Specific examples include the observation that androgens regulate the expression of the enzyme transmembrane protease, serine 2 which facilitates severe acute respiratory syndrome coronavirus 2 viral entry into the cell; therefore, androgen deprivation therapy is being explored as a treatment option in males infected with COVID-19. An immunophenotyping study of COVID-19 patients has shown that a subset develop T cytopenia which has prompted a clinical trial that is testing the efficacy of interleukin-7 in these patients. Predicting which COVID-19 patients will develop progressive disease that will require hospitalization has important implications for clinical trials that target outpatients. Enrollment of patients at low risk for progression of disease and hospitalization would likely not result in such therapy demonstrating efficacy. There are efforts to use artificial intelligence to integrate digital data from smartwatch applications or digital monitoring systems and biological data to enable identification of the high risk COVID-19 patient. The ultimate goal of precision medicine using such modern technology is to recognize individual differences to improve health for all.

Current understanding of the influence of environmental factors on SARS-CoV-2 transmission, persistence, and infectivity

Coronavirus disease 2019 (COVID-19) has emerged as a significant public health emergency in recent times. It is a respiratory illness caused by the novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which was initially reported in late December 2019. In a span of 6 months, this pandemic spread across the globe leading to high morbidity and mortality rates. Soon after the identification of the causative virus, questions concerning the impact of environmental factors on the dissemination and transmission of the virus, its persistence in environmental matrices, and infectivity potential begin to emerge. As the environmental factors could have far-reaching consequences on infection dissemination and severity, it is essential to understand the linkage between these factors and the COVID-19 outbreak. In order to improve our current understanding over this topic, the present article summarizes topical and substantial observations made regarding the influences of abiotic environmental factors such as climate, temperature, humidity, wind speed, air, and water quality, solid surfaces/interfaces, frozen food, and biotic factors like age, sex, gender, blood type, population density, behavioural characteristics, etc. on the transmission, persistence, and infectivity of this newly recognized SARS-CoV-2 virus. Further, the potential pathways of virus transmission that could pose risk to population health have been discussed, and the critical areas have been identified which merits urgent research for the assessment and management of the COVID-19 outbreak. Where possible, the knowledge gaps requiring further investigation have been highlighted.

Transcriptomic Analysis of Respiratory Tissue and Cell Line Models to Examine Glycosylation Machinery during SARS-CoV-2 Infection

Glycosylation, being the most abundant post-translational modification, plays a profound role affecting expression, localization and function of proteins and macromolecules in immune response to infection. Presented are the findings of a transcriptomic analysis performed using high-throughput functional genomics data from public repository to examine the altered transcription of the human glycosylation machinery in response to SARS-CoV-2 stimulus and infection. In addition to the conventional in silico functional enrichment analysis methods we also present results from the manual analysis of biomedical literature databases to bring about the biological significance of glycans and glycan-binding proteins in modulating the host immune response during SARS-CoV-2 infection. Our analysis revealed key immunomodulatory lectins, proteoglycans and glycan epitopes implicated in exerting both negative and positive downstream inflammatory signaling pathways, in addition to its vital role as adhesion receptors for SARS-CoV-2 pathogen. A hypothetical correlation of the differentially expressed human glycogenes with the altered host inflammatory response and the cytokine storm-generated in response to SARS-CoV-2 pathogen is proposed. These markers can provide novel insights into the diverse roles and functioning of glycosylation pathways modulated by SARS-CoV-2, provide avenues of stratification, treatment, and targeted approaches for COVID-19 immunity and other viral infectious agents.

The Impact of ABO Blood Grouping on COVID-19 Vulnerability and Seriousness: A Retrospective Cross-Sectional Controlled Study among the Arab Community

Background and Objectives: Studies have noted that some ABO blood types are more susceptible to COVID-19 virus infection. This study aimed to further confirm the relationship between different blood groups on the vulnerability, symptoms, cure period, and severity among COVID-19 recovered patients. Subjects and Methods: This cross-sectional study approached the participants from the Arab community via social media (mainly Facebook and WhatsApp). The data were collected through two Google Form questionnaires, one for COVID-19 recovered patients (COVID-19 group, n = 726), and the other for the healthy people (Control group, n = 707). Results: The subjects with blood group O were the least likely to be infected with the COVID-19 virus, while those with blood group A were not likely to be the most susceptible. There were significant differences among different ABO blood groups regarding the distribution of oxygen saturation percentage, myalgia, and recovery time after COVID-19 infection (p < 0.01, 0.01, and 0.05, respectively). The blood group A showed the highest percentage of patients who experienced an oxygen saturation range of 90-100%, whereas the blood group O showed the highest percentage of patients who experienced an oxygen saturation range of 70-80%. The blood group A showed the lowest percentage of patients who required artificial respiration, whereas the blood group O showed the highest percentage of patients who required artificial respiration. The blood group B showed the lowest percentage of patients who experienced myalgia and exhibited the lowest percentage of patients who needed 3 weeks or more to recover. Conclusion: The people of blood group O may be the least likely to be infected with COVID-19, however, they may be the more in need of treatment in hospital and artificial respiration compared to the other blood groups.

Association between ABO blood groups and susceptibility to COVID-19: profile of age and gender in Iraqi patients

Background

A case-control study was performed to examine age, gender, and ABO blood groups in 1014 Iraqi hospitalized cases with Coronavirus disease 2019 (COVID-19) and 901 blood donors (control group). The infection was molecularly diagnosed by detecting coronavirus RNA in nasal swabs of patients.

Results

Mean age was significantly elevated in cases compared to controls (48.2 ± 13.8 vs. 29.9 ± 9.0 year; probability [p] < 0.001). Receiver operating characteristic analysis demonstrated the predictive significance of age in COVID-19 evolution (Area under curve = 0.858; 95% CI: 0.841 - 0.875; p < 0.001). Males outnumbered females in cases (60.4 vs. 39.6%) and controls (56 vs. 44%). Stratification by age group (< 30, 30 - 39, 40 - 49 and ≥ 50 years) revealed that 48.3% of cases clustered in the age group ≥ 50 years. ABO blood group analysis showed that group A was the most common among cases, while group O was the most common among controls (35.5 and 36.7%, respectively). Blood groups A (35.5 vs. 32.7; corrected p [pc] = 0.021), A+AB (46.3 vs. 41.7%; pc = 0.021) and A+B+AB (68.0 vs. 63.3%; pc = 0.007) showed significantly elevated frequencies in cases compared to controls. Logistic regression analysis estimated odds ratios (ORs) of 1.53 (95% confidence interval [CI]: 1.16 - 2.02), 1.48 (95% CI: 1.14 - 1.93) and 1.50 (95% CI: 1.17 - 1.82) for blood groups A, A+AB and A+B+AB, respectively. Blood group frequencies showed no significant differences between age groups of cases or controls. Regarding gender, male cases were marked with increased frequency of group A (39.9 vs. 28.9%) and decreased frequency of group O (25.9 vs. 41.0%) compared to female cases. Independent re-analysis of ABO blood groups in male and female cases demonstrated that group A was increased in male cases compared to male controls (39.9 vs. 33.1%; OR = 1.65; 95% CI: 1.24 - 2.21; pc = 0.006). On the contrary, no significant differences were found between females of cases and controls.

Conclusions

The study results indicated that blood group A may be associated with an increased risk of developing COVID-19, particularly in males.

The potential use of ABO blood group system for risk stratification of COVID-19

ABO blood groups is a cheap and affordable test that can be immediately retrieved from COVID-19 patients at the diagnosis. There is increasing evidence that non-O blood groups have both higher susceptibility and higher severity of COVID-19 infections. The reason behind such relationship seems elusive. Regarding susceptibility, Non-O individuals have Anti-A antibodies which can prevent viral entry across ACE-2 receptors, moreover, Non-O individuals are at higher risk of autoimmunity, hypercoagulable state, and dysbiosis resulting in an augmented tendency for vascular inflammatory sequelae of COVID-19. We can conclude, on the diagnostic level, that ABO blood groups can be potentially used for risk stratification of affected COVID-19 patients, to anticipate the deterioration of patients at higher risk for complications. On a therapeutic level, plasma from normal O blood group individuals might potentially replace the use of convalescent serum for the treatment of COVID-19.

Individuals with a Rh-positive but not Rh-negative blood group are more vulnerable to SARS-CoV-2 infection: demographics and trend study on COVID-19 cases in Sudan

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In Sudan, several haematological studies were conducted to study the ABO blood group distribution among the population, in which the O blood group was dominant followed by the A blood group. However, there is no systematic study into any correlation between COVID-19 and the population's blood group types, therefore we have intended to study the possible effect of blood group on the acquisition of SARS-CoV-2 infection. A questionnaire-based case-control study was carried out on 557 individuals with COVID-19 in Sudan; factors such as age, blood group, previous malaria infection, history of ailments such as diabetes, hypertension and symptoms suffered were also considered and analysed. More women were infected than men, and individuals between 25 and 35 years were the most affected age group. O Rhesus-positive (O+) blood group was the least affected by the disease while A Rhesus-positive (A+) individuals were the most vulnerable. Fatigue, fever and loss of smell were the major symptoms among the patients, but 13% of SARS-COV-2-positive individuals remained asymptomatic. As the Sudan population is largely constituted of O Rhesus-positive inhabitants (approximately 50%) these results might explain the relatively lower COVID-19 incidence in the country.