Imbalanced Angiogenesis in Pregnancies Complicated by SARS-CoV-2 Infection

COVID-19 and preeclampsia (preE) share the ANG-II mediated endothelial dysfunction, resulting from a significant dysregulation of RAS and an imbalanced proportion of anti-angiogenic and pro-angiogenic soluble plasmatic factors. Of note, an increased incidence of preE has been reported among COVID-19-infected mothers compared to the general pregnant population. The two most promising angiogenic markers are the soluble fms-like tyrosine kinase receptor-1 (sFlt-1), the major antiangiogenic factor, and the placental growth factor (PlGF), a powerful angiogenic factor. Since these markers have proven useful in the prediction, diagnosis, and severity of preE, this study aimed to evaluate their maternal serum levels in pregnancies complicated by SARS-CoV-2 infection and to assess their potential use to guide the management of these women. A retrospective analysis of SARS-CoV-2-positive pregnant women was performed. The serum levels of sFlt-1 and PlGF were collected at the diagnosis of SARS-CoV-2 infection at the hospital, before the beginning of steroid/hydroxychloroquine and/or antithrombotic therapy. The sFlt-1/PlGF ratio was stratified using cut-off values clinically utilized in the diagnosis and prediction of preE (low < 38, intermediate 38–85/110* and high >85/110*, * if before or after the 34th week of gestation). A total of 57 women were included, of whom 20 (35%) had signs and symptoms of COVID-19 at hospital presentation and 37 (65%) were asymptomatic. None were vaccinated. The mean gestational age at diagnosis of SARS-CoV-2 infection was 32 weeks in symptomatic patients and 37 weeks and 5 days in asymptomatic ones (p = 0.089). sFlt-1 serum levels were higher in SARS-CoV-2 positive asymptomatic patients compared to women with COVID-19 related symptoms (4899 ± 4357 pg/mL vs. 3187 ± 2426 pg/mL, p = 0.005). sFlt-1/PlGF at admission was <38 in 18 of the 20 symptomatic women (90%) compared to 22 (59%) of the asymptomatic patients (p = 0.018). Of note, two of the three women admitted to the intensive care unit had a very low ratio (<2). In turn, rates of patients with sFlt-1/PlGF at admission > 85/110 were not significantly different between the two groups: 11% in asymptomatic patients (4/37) vs. none of the symptomatic patients (p = 0.286), and all of them presented a placental dysfunction, like preE (n = 1) and FGR (n = 3). Of note, there were no stillbirths or maternal or neonatal deaths among symptomatic patients; also, no cases of preE, FGR, or small for gestational age neonates were diagnosed. In conclusion, our data suggest that SARS-CoV-2 infection during pregnancy could influence the angiogenic balance. A significant pathological alteration of the sFlt-1/PlGF ratio cannot be identified during the symptomatic phase; however, if left untreated, SARS-CoV-2 infection could potentially trigger placental dysfunction.     

IFITM3 Inhibits SARS-CoV-2 Infection and Is Associated with COVID-19 Susceptibility

SARS-CoV-2 has become a global threat to public health. Infected individuals can be asymptomatic or develop mild to severe symptoms, including pneumonia, respiratory distress, and death. This wide spectrum of clinical presentations of SARS-CoV-2 infection is believed in part due to the polymorphisms of key genetic factors in the population. In this study, we report that the interferon-induced antiviral factor IFITM3 inhibits SARS-CoV-2 infection by preventing SARS-CoV-2 spike-protein-mediated virus entry and cell-to-cell fusion. Analysis of a Chinese COVID-19 patient cohort demonstrates that the rs12252 CC genotype of IFITM3 is associated with SARS-CoV-2 infection risk in the studied cohort. These data suggest that individuals carrying the rs12252 C allele in the IFITM3 gene may be vulnerable to SARS-CoV-2 infection and thus may benefit from early medical intervention.     

Cardiovascular Tropism and Sequelae of SARS-CoV-2 Infection

The extrapulmonary manifestation of coronavirus disease-19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), became apparent early in the ongoing pandemic. It is now recognized that cells of the cardiovascular system are targets of SARS-CoV-2 infection and associated disease pathogenesis. While some details are emerging, much remains to be understood pertaining to the mechanistic basis by which SARS-CoV-2 contributes to acute and chronic manifestations of COVID-19. This knowledge has the potential to improve clinical management for the growing populations of patients impacted by COVID-19. Here, we review the epidemiology and pathophysiology of cardiovascular sequelae of COVID-19 and outline proposed disease mechanisms, including direct SARS-CoV-2 infection of major cardiovascular cell types and pathogenic effects of non-infectious viral particles and elicited inflammatory mediators. Finally, we identify the major outstanding questions in cardiovascular COVID-19 research.     

Minimal transmission of SARS-CoV-2 from paediatric COVID-19 cases in primary schools,Norway, August to November 2020

An intense debate on school closures to control the COVID-19 pandemic is ongoing in Europe. We prospectively examined transmission of SARS-CoV-2 from confirmed paediatric cases in Norwegian primary schools between August and November 2020. All in-school contacts were systematically tested twice during their quarantine period. With preventive measures implemented in schools, we found minimal child-to-child (0.9%, 2/234) and child-to-adult (1.7%, 1/58) transmission, supporting that under 14 year olds are not the drivers of SARS-CoV-2 transmission.     

Distinct evolutionary trajectories of SARS-CoV-2-interacting proteins in bats and primates identify important host determinants of COVID-19

The coronavirus disease 19 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a coronavirus that spilled over from the bat reservoir. Despite numerous clinical trials and vaccines, the burden remains immense, and the host determinants of SARS-CoV-2 susceptibility and COVID-19 severity remain largely unknown. Signatures of positive selection detected by comparative functional genetic analyses in primate and bat genomes can uncover important and specific adaptations that occurred at virus–host interfaces. We performed high-throughput evolutionary analyses of 334 SARS-CoV-2-interacting proteins to identify SARS-CoV adaptive loci and uncover functional differences between modern humans, primates, and bats. Using DGINN (Detection of Genetic INNovation), we identified 38 bat and 81 primate proteins with marks of positive selection. Seventeen genes, including the ACE2 receptor, present adaptive marks in both mammalian orders, suggesting common virus–host interfaces and past epidemics of coronaviruses shaping their genomes. Yet, 84 genes presented distinct adaptations in bats and primates. Notably, residues involved in ubiquitination and phosphorylation of the inflammatory RIPK1 have rapidly evolved in bats but not primates, suggesting different inflammation regulation versus humans. Furthermore, we discovered residues with typical virus–host arms race marks in primates, such as in the entry factor TMPRSS2 or the autophagy adaptor FYCO1, pointing to host-specific in vivo interfaces that may be drug targets. Finally, we found that FYCO1 sites under adaptation in primates are those associated with severe COVID-19, supporting their importance in pathogenesis and replication. Overall, we identified adaptations involved in SARS-CoV-2 infection in bats and primates, enlightening modern genetic determinants of virus susceptibility and severity.

The current coronavirus disease 19 (COVID-19) pandemic already led to over six million human deaths (WHO April 2022). The causative agent is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated from viral cross-species transmission from the bat reservoir, directly or through an intermediate host, to humans (1). Bats naturally host some of the most high-profile zoonotic viruses, including SARS-CoVs, without apparent symptoms (2). Despite prevention measures and effective vaccines, the burden from COVID-19 remains immense in humans, and the determinants of SARS-CoV-2 susceptibility and COVID-19 severity remain largely unknown. A powerful way to identify these factors is to use comparative functional genomics to map host–virus interfaces that underlie infections in the bat reservoir and the primate host (3).During infection, viruses interact with many host proteins, or viral-interacting proteins (VIPs). While some VIPs are usurped for viral replication away from their normal host functions, some are specifically targeting the virus as part of the host antiviral immune defense. Since the emergence of SARS-CoV-2, VIPs have been identified in hundreds of screens using in vitro approaches, such as CRISPR/knockout screens, complementary DNA library screens, or mass spectrometry analyses (4, 5). However, the in vivo importance of the identified SARS-CoV-2 VIPs remains largely unknown.From an evolutionary standpoint, the fitness cost imposed by pathogenetic viruses triggers strong selective pressures on VIPs, such that those VIPs able to prevent, or better counteract, viral infection will quickly become fixed in host populations. In turn, host adaptations push viral proteins into recurring counter adaptation cycles creating stereotypical virus–host molecular arms races. These arms races are witnessed by signatures of accelerated rates of evolution, or positive selection, over functionally important residues and domains in VIPs (6–8). Thus, when combined with functional data, identifying the VIPs with signatures of positive selection is a powerful way to discover virus–host interfaces (e.g., refs. 9–11).When studies of adaptive signatures in host genes are combined with human clinical studies or genome-wide association studies (GWAS), they are powerful to uncover the importance of gene evolution and variants in disease severity (e.g., refs. 12, 13). Interestingly, several genetic loci associated with COVID-19 severity and susceptibility in humans, such as OAS1 (2''-5′-Oligoadenylate Synthetase 1) or those from the interferon signaling pathway (12, 14–19), bear hallmarks of such adaptive arms races. Furthermore, dozens of VIPs that bear marks of adaptive evolution in the human lineage from ancient SARS-CoV epidemics may be important host determinants of SARS-CoV-2 (20).Here, we aimed to identify key SARS-CoV adaptive loci and functional genomic differences between bats, which include the natural reservoir of SARS-CoVs, and primates, including humans. We performed high-throughput evolutionary and positive selection screens of 334 SARS-CoV-2-interacting proteins (4) using the Detection of Genetic INNovation (DGINN) pipeline (21), followed by comprehensive (phylo)genetic analyses of seven VIPs of interest. We provide the results in the searchable VirHostNet 2.0 web portal. Using this approach, we identified 38 bat and 81 primate genes with strong evidence of positive selection. Of these, we found 17 proteins, including the ACE2 receptor, subjected to adaptative evolution in both clades, 1) confirming that past SARS-CoV epidemics occurred during both bat and primate evolution, and 2) identifying core VIPs that shaped universal SARS-CoV–host molecular arms races. We also identified 84 VIPs with lineage-specific adaptations that likely contributed to SARS-CoV pathogenicity in different mammalian hosts. Among these, we uncover the important role of several genes, including TMPRSS2, FYCO1 (FYVE and coiled-coil domain containing 1), or RIPK1 that play important roles in entry, trafficking, or inflammatory responses, respectively. We hypothesize that these past adaptation events in bats and primates underlie differences in susceptibility to SARS-CoV-2 infections and key determinants in COVID-19 severity in modern humans.     

Human Cell Organelles in SARS-CoV-2 Infection: An Up-to-Date Overview

Since the end of 2019, the whole world has been struggling with the life-threatening pandemic amongst all age groups and geographic areas caused by Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2). The Coronavirus Disease 2019 (COVID-19) pandemic, which has led to more than 468 million cases and over 6 million deaths reported worldwide (as of 20 March 2022), is one of the greatest threats to human health in history. Meanwhile, the lack of specific and irresistible treatment modalities provoked concentrated efforts in scientists around the world. Various mechanisms of cell entry and cellular dysfunction were initially proclaimed. Especially, mitochondria and cell membrane are crucial for the course of infection. The SARS-CoV-2 invasion depends on angiotensin converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), and cluster of differentiation 147 (CD147), expressed on host cells. Moreover, in this narrative review, we aim to discuss other cell organelles targeted by SARS-CoV-2. Lastly, we briefly summarize the studies on various drugs.     

SARS-CoV-2-host dynamics: Increased risk of adverse outcomes of COVID-19 in obesity

Background and aimThe pandemic of COVID-19 has put forward the public health system across countries to prepare themselves for the unprecedented outbreak of the present time. Recognition of the associated risks of morbidity and mortality becomes not only imperative but also fundamental to determine the prevention strategies as well as targeting the high-risk populations for appropriate therapies.MethodsWe reviewed, collated and analysed the online database i.e. Pubmed, Google scholar, Researchgate to highlight the demographic and mechanistic link between obesity and associated risks of severity in COVID-19.ResultsWe observed a changing dynamic in the reporting from the time of initial pandemic in China to currently reported research. While, initially body mass index (BMI) did not find a mention in the data, it is now clearly emerging that obesity is one of the profound risk factors for complications of COVID-19.ConclusionOur review will help clinicians and health policy makers in considering the importance of obesity in making the prevention and therapeutic strategies of COVID-19. An extra attention and precaution for patients with obesity in COVID-19 pandemic is recommended.     

Human ACE2 Polymorphisms from Different Human Populations Modulate SARS-CoV-2 Infection

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in over 6 million deaths worldwide. The high variability in COVID-19 symptoms remains one of the most interesting mysteries of the pandemic. Genetic and environmental factors are likely to be key determinants of COVID-19 symptomatology. Here, we explored ACE2 as a genetic determinant for SARS-CoV-2 infection and COVID-19 symptomatology. Each human genome encodes two alleles of ACE2, which encodes the cell entry receptor for SARS-CoV-2. Here, we determined whether naturally occurring human ACE2 (hACE2) polymorphisms in the human population affect SARS-CoV-2 infection and the severity of COVID-19 symptoms. ACE2 variants S19P, I21V, E23K, K26R, K31R, N33I, H34R, E35K, and T92I showed increased virus infection compared to wild-type ACE2; thus, these variants could increase the risk for COVID-19. In contrast, variants D38V, Y83H, I468V, and N638S showed reduced infection, indicating a potential protective effect. hACE2 variants K26R and T92I increased infection by three-fold without changing the levels of ACE2 on the surface of the cells, suggesting that these variants may increase the risk of severe COVID-19. On the contrary, hACE2 variants D38V and Y83H decreased SARS-CoV-2 infection by four- and ten-fold, respectively, without changing surface expression, suggesting that these variants may protect against severe COVID-19. Remarkably, all protective hACE2 Polymorphisms were found almost exclusively in Asian populations, which may provide a partial explanation for the low COVID-19 mortality rates in Asian countries. Thus, hACE2 polymorphisms may modulate susceptibility to SARS-CoV-2 in the host and partially account for the differences in severity of COVID-19 among different ethnic groups.     

New-Onset and Relapsed Membranous Nephropathy post SARS-CoV-2 and COVID-19 Vaccination

Since the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak and COVID-19 vaccination, new-onset and relapsed clinical cases of membranous nephropathy (MN) have been reported. However, their clinical characteristics and pathogenesis remained unclear. In this article, we collected five cases of MN associated with SARS-CoV-2 infection and 37 related to COVID-19 vaccination. Of these five cases, four (4/5, 80%) had acute kidney injury (AKI) at disease onset. Phospholipase A2 receptor (PLA2R) in kidney tissue was negative in three (3/5, 60%) patients, and no deposition of virus particles was measured among all patients. Conventional immunosuppressive drugs could induce disease remission. The underlying pathogenesis included the subepithelial deposition of viral antigens and aberrant immune response. New-onset and relapsed MN after COVID-19 vaccination generally occurred within two weeks after the second dose of vaccine. Almost 27% of patients (10/37) suffered from AKI. In total, 11 of 14 cases showed positive for PLA2R, and 20 of 26 (76.9%) presented with an elevated serum phospholipase A2 receptor antibody (PLA2R-Ab), in which 8 cases exceeded 50 RU/mL. Conventional immunosuppressive medications combined with rituximab were found more beneficial to disease remission for relapsed patients. In contrast, new-onset patients responded to conservative treatment. Overall, most patients (24/37, 64.9%) had a favorable prognosis. Cross immunity and enhanced immune response might contribute to explaining the mechanisms of MN post COVID-19 vaccination.     

Indian Publications on SARS-CoV-2: A bibliometric study of WHO COVID-19 database

Background & aimsNowadays, the whole World is under threat of Coronavirus disease (COVID-19). The ongoing COVID-19 pandemic has resulted in many fatalities and forced scientific communities to foster their Research and Development (R&D) activities. As a result, there is an enormous growth of scholarly literature on the subject. We here in this study have assessed the Indian publications contributions on COVID-19.MethodsWHO is curating global scientific literature on coronavirus since it declared COVID-19 a global pandemic through Global Research Database on COVID-19. The present study analyzed Indian publications on SARS-CoV-2 as found in WHO COVID-19 database. The research data was restricted for the period of March 2, 2020 to May 12, 2020.ResultsThe study found that there is a considerable and constant growth of Indian publications on COVID-19 from mid-April. It is interesting to note that, the most prolific authors belong to either AIIMS or ICMR institutes. Delhi state contributed highest number of publications on COVID-19. The AIIMS, New Delhi was the most productive institution in terms of publications. The Indian Journal of Medical Research has emerged as the productive journal contributing highest number of the publications. In terms of research area, the majority of the publications were related to Epidemiology.ConclusionsThe highly cited publications were of evidenced based studies. It is observed that the studies pertaining to virology, diagnosis and treatment, clinical features etc. have received highest citations than general studies on epidemiology or pandemic.     

Effect of Previous COVID-19 Vaccination on Humoral Immunity 3 Months after SARS-CoV-2 Omicron Infection and Booster Effect of a Fourth COVID-19 Vaccination 2 Months after SARS-CoV-2 Omicron Infection

In this study, we aimed to determine the effect of COVID-19 vaccination on 3-month immune response and durability after natural infection by the Omicron variant and to assess the immune response to a fourth dose of COVID-19 vaccination in patients with prior natural infection with the Omicron variant. Overall, 86 patients aged ≥60 years with different vaccination histories and 39 health care workers (HCWs) vaccinated thrice before Omicron infection were enrolled. The sVNT50 titer was significantly lower in patients with incomplete vaccination before SARS-CoV-2 infection with the S clade (p < 0.001), Delta variant (p < 0.001), or Omicron variant (p = 0.003) than in those vaccinated thrice. The sVNT results against the Omicron variant did not differ significantly in patients aged ≥60 years (p = 0.49) and HCWs (p = 0.17), regardless of the recipient receiving the fourth dose 2 months after COVID-19. Incomplete COVID-19 vaccination before Omicron infection for individuals aged ≥60 years conferred limited protection against homologous and heterologous virus strains, whereas two or three doses of the vaccine provided cross-variant humoral immunity against Omicron infection for at least 3 months. However, a fourth dose 2 months after Omicron infection did not enhance immunity against the homologous strain. A future strategy using the bivalent Omicron-containing booster vaccine with appropriate timing will be crucial.     

Chemiluminescence Immunoassay Based Serological Immunoassays for Detection of SARS-CoV-2 Neutralizing Antibodies in COVID-19 Convalescent Patients and Vaccinated Population

The development of rapid serological detection methods re urgently needed for determination of neutralizing antibodies in sera. In this study, four rapid methods (ACE2-RBD inhibition assay, S1-IgG detection, RBD-IgG detection, and N-IgG detection) were established and evaluated based on chemiluminescence technology. For the first time, a broadly neutralizing antibody with high affinity was used as a standard for the quantitative detection of SARS-CoV-2 specific neutralizing antibodies in human sera. Sera from COVID-19 convalescent patients (N = 119), vaccinated donors (N = 86), and healthy donors (N = 299) confirmed by microneutralization test (MNT) were used to evaluate the above methods. The result showed that the ACE2-RBD inhibition assay calculated with either ACE2-RBD binding inhibition percentage rate or ACE2-RBD inhibiting antibody concentration were strongly correlated with MNT (r ≥ 0.78, p < 0.0001) and also highly consistent with MNT (Kappa Value ≥ 0.94, p < 0.01). There was also a strong correlation between the two evaluation indices (r ≥ 0.99, p < 0.0001). Meanwhile, S1-IgG and RBD-IgG quantitative detection were also significantly correlated with MNT (r ≥ 0.73, p < 0.0001), and both methods were highly correlated with each other (r ≥ 0.95, p < 0.0001). However, the concentration of N-IgG antibodies showed a lower correlation with the MNT results (r < 0.49, p < 0.0001). The diagnostic assays presented here could be used for the evaluation of SARS-CoV-2 vaccine immunization effect and serological diagnosis of COVID-19 patients, and could also have guiding significance for establishing other rapid serological methods to surrogate neutralization tests for SARS-CoV-2.     

Angiotensin converting enzyme-2 as therapeutic target in COVID-19

The pandemic of coronavirus disease 2019 (COVID-19) is a global health emergency that poses a significant threat to world people’s health. This outbreak causes major challenges to healthcare systems. Given the lack of effective treatments or vaccine for it, the identification of novel and safe drugs against COVID-19 infection is an urgent need. Angiotensin-converting enzyme 2 (ACE2) is not only an entry receptor of the SARS-CoV-2 virus, the virus that causes COVID-19, but also can protect from lung injury. In this view, we highlighted potential approaches to address ACE2-mediated SARS-CoV-2 virus, including 1) delivering an excessive soluble form of ACE2 (recombinant human ACE2: rhACE2) and 2) inhibition of the interaction between SARS-CoV-2 virus and ACE2 by some compounds with competitive effects (morphine and codeine). Further clinical trials in this regard can reveal a more definite conclusion against the COVID-19 disaster.     

COVID-19 and Neurological Impairment: Hypothalamic Circuits and Beyond

In December 2019, a novel coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan, the capital of Hubei, China. The virus infection, coronavirus disease 2019 (COVID-19), represents a global concern, as almost all countries around the world are affected. Clinical reports have confirmed several neurological manifestations in COVID-19 patients such as headaches, vomiting, and nausea, indicating the involvement of the central nervous system (CNS) and peripheral nervous system (PNS). Neuroinvasion of coronaviruses is not a new phenomenon, as it has been demonstrated by previous autopsies of severe acute respiratory syndrome coronavirus (SARS-CoV) patients who experienced similar neurologic symptoms. The hypothalamus is a complex structure that is composed of many nuclei and diverse neuronal cell groups. It is characterized by intricate intrahypothalamic circuits that orchestrate a finely tuned communication within the CNS and with the PNS. Hypothalamic circuits are critical for maintaining homeostatic challenges including immune responses to viral infections. The present article reviews the possible routes and mechanisms of neuroinvasion of SARS-CoV-2, with a specific focus on the role of the hypothalamic circuits in mediating the neurological symptoms noted during COVID-19 infection.     

Characterizing Kinetics and Avidity of SARS-CoV-2 Antibody Responses in COVID-19 Greek Patients

In-depth understanding of the immune response provoked by SARS-CoV-2 infection is necessary, as there is a great risk of reinfection and a difficulty in achieving herd immunity due to a decline in both antibody concentration and avidity. Avidity testing, however, could overcome variability in the immune response associated with sex or clinical symptoms, and thus differentiate between recent and past infections. In this context, here, we analyzed SARS-CoV-2 antibody kinetics and avidity in Greek hospitalized (26%) and non-hospitalized (74%) COVID-19 patients (N = 71) in the course of up to 15 months after their infection to improve the accuracy of the serological diagnosis in dating the onset of the infection. The results showed that IgG-S1 levels decline significantly at four months (p = 0.0239) in both groups of patients and are higher in hospitalized ones (up to 2.1-fold, p < 0.001). Additionally, hospitalized patients’ titers drop greatly and are equalized to non-hospitalized ones only at a time-point of twelve to fifteen months. Antibody levels of women in total remain more stable months after infection, compared to men. Furthermore, we examined the differential maturation of IgG avidity after SARS-CoV-2 infection, showing an incomplete maturation of avidity that results in a plateau at four months after infection. We also defined 38.2% avidity (sensitivity: 58.9%, specificity: 90.91%) as an appropriate “cut-off” that could be used to determine the stage of infection before avidity reaches a plateau.     

Implications of the Immune Polymorphisms of the Host and the Genetic Variability of SARS-CoV-2 in the Development of COVID-19

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the current pandemic affecting almost all countries in the world. SARS-CoV-2 is the agent responsible for coronavirus disease 19 (COVID-19), which has claimed millions of lives around the world. In most patients, SARS-CoV-2 infection does not cause clinical signs. However, some infected people develop symptoms, which include loss of smell or taste, fever, dry cough, headache, severe pneumonia, as well as coagulation disorders. The aim of this work is to report genetic factors of SARS-CoV-2 and host-associated to severe COVID-19, placing special emphasis on the viral entry and molecules of the immune system involved with viral infection. Besides this, we analyze SARS-CoV-2 variants and their structural characteristics related to the binding to polymorphic angiotensin-converting enzyme type 2 (ACE2). Additionally, we also review other polymorphisms as well as some epigenetic factors involved in the immunopathogenesis of COVID-19. These factors and viral variability could explain the increment of infection rate and/or in the development of severe COVID-19.     

SARS-CoV-2 Infection and C-Section: A Prospective Observational Study

Pregnant women are particularly vulnerable to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. In addition to unfavorable perinatal outcomes, there has been an increase in obstetric interventions. With this study, we aimed to clarify the reasons, using Robson’s classification model, and risk factors for cesarean section (C-section) in SARS-CoV-2-infected mothers and their perinatal results. This was a prospective observational study that was carried out in 79 hospitals (Spanish Obstetric Emergency Group) with a cohort of 1704 SARS-CoV-2 PCR-positive pregnant women that were registered consecutively between 26 February and 5 November 2020. The data from 1248 pregnant women who delivered vaginally (vaginal + operative vaginal) was compared with those from 456 (26.8%) who underwent a C-section. C-section patients were older with higher rates of comorbidities, in vitro fertilization and multiple pregnancies (p < 0.05) compared with women who delivered vaginally. Moreover, C-section risk was associated with the presence of pneumonia (p < 0.001) and 41.1% of C-sections in patients with pneumonia were preterm (Robson’s 10th category). However, delivery care was similar between asymptomatic and mild–moderate symptomatic patients (p = 0.228) and their predisposing factors to C-section were the presence of uterine scarring (due to a previous C-section) and the induction of labor or programmed C-section for unspecified obstetric reasons. On the other hand, higher rates of hemorrhagic events, hypertensive disorders and thrombotic events were observed in the C-section group (p < 0.001 for all three outcomes), as well as for ICU admission. These findings suggest that this type of delivery was associated with the mother’s clinical conditions that required a rapid and early termination of pregnancy.