Macrophage ACE2 is necessary for SARS-CoV-2 replication and subsequent cytokine responses that restrict continued virion release.

Macrophages are key cellular contributors to the pathogenesis of COVID-19, the disease caused by the virus SARS-CoV-2. The SARS-CoV-2 entry receptor ACE2 is present only on a subset of macrophages at sites of SARS-CoV-2 infection in humans. Here, we investigated whether SARS-CoV-2 can enter macrophages, replicate, and release new viral progeny; whether macrophages need to sense a replicating virus to drive cytokine release; and, if so, whether ACE2 is involved in these mechanisms. We found that SARS-CoV-2 could enter, but did not replicate within, ACE2-deficient human primary macrophages and did not induce proinflammatory cytokine expression. By contrast, ACE2 overexpression in human THP-1-derived macrophages permitted SARS-CoV-2 entry, processing and replication, and virion release. ACE2-overexpressing THP-1 macrophages sensed active viral replication and triggered proinflammatory, antiviral programs mediated by the kinase TBK-1 that limited prolonged viral replication and release. These findings help elucidate the role of ACE2 and its absence in macrophage responses to SARS-CoV-2 infection.

Developmental Programming in Animal Models: Critical Evidence of Current Environmental Negative Changes.

The Developmental Origins of Health and Disease (DOHaD) approach answers questions surrounding the early events suffered by the mother during reproductive stages that can either partially or permanently influence the developmental programming of children, predisposing them to be either healthy or exhibit negative health outcomes in adulthood. Globally, vulnerable populations tend to present high obesity rates, including among school-age children and women of reproductive age. In addition, adults suffer from high rates of diabetes, hypertension, cardiovascular, and other metabolic diseases. The increase in metabolic outcomes has been associated with the combination of maternal womb conditions and adult lifestyle-related factors such as malnutrition and obesity, smoking habits, and alcoholism. However, to date, "new environmental changes" have recently been considered negative factors of development, such as maternal sedentary lifestyle, lack of maternal attachment during lactation, overcrowding, smog, overurbanization, industrialization, noise pollution, and psychosocial stress experienced during the current SARS-CoV-2 pandemic. Therefore, it is important to recognize how all these factors impact offspring development during pregnancy and lactation, a period in which the subject cannot protect itself from these mechanisms. This review aims to introduce the importance of studying DOHaD, discuss classical programming studies, and address the importance of studying new emerging programming mechanisms, known as actual lifestyle factors, during pregnancy and lactation.

Ancestral SARS-CoV-2, but not Omicron, replicates less efficiently in primary pediatric nasal epithelial cells.

Children typically experience more mild symptoms of Coronavirus Disease 2019 (COVID-19) when compared to adults. There is a strong body of evidence that children are also less susceptible to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection with the ancestral viral isolate. However, the emergence of SARS-CoV-2 variants of concern (VOCs) has been associated with an increased number of pediatric infections. Whether this is the result of widespread adult vaccination or fundamental changes in the biology of SARS-CoV-2 remain to be determined. Here, we use primary nasal epithelial cells (NECs) from children and adults, differentiated at an air-liquid interface to show that the ancestral SARS-CoV-2 replicates to significantly lower titers in the NECs of children compared to those of adults. This was associated with a heightened antiviral response to SARS-CoV-2 in the NECs of children. Importantly, the Delta variant also replicated to significantly lower titers in the NECs of children. This trend was markedly less pronounced in the case of Omicron. It is also striking to note that, at least in terms of viral RNA, Omicron replicated better in pediatric NECs compared to both Delta and the ancestral virus. Taken together, these data show that the nasal epithelium of children supports lower infection and replication of ancestral SARS-CoV-2, although this may be changing as the virus evolves.

Perspectives of healthcare workers in South Africa on COVID-19 vaccination passports.

Background: Following the rollout of several effective vaccines against coronavirus disease 2019 (COVID-19), many countries have introduced vaccination passports or certificates as a means of certifying that an individual has been vaccinated against, is immune to, or is presently uninfected with COVID-19. An extensive ethical debate has ensued. Aim: To determine the perspectives of South African healthcare workers (HCWs) on the implementation of COVID-19 vaccination passports (C19VPs) in South Africa (SA). Setting: Healthcare workers working in various fields and practice settings throughout SA were invited to complete an online questionnaire. Methods: An online questionnaire was distributed using convenience sampling via social media platforms to HCWs over a 1-month period, collecting demographic details and responses to 8 Likert-type items regarding agreement with C19VPs, ethical issues and feasibility. Each item was graded from 1 (strongly disagree) to 5 (strongly agree), with grouping of 4 of the 8 items exploring a common theme of C19VPs being a good idea, constituting a score out of 20. Non-parametric tests were performed to determine differences in responses between groups. Results: One thousand HCWs responded to the survey and fulfilled inclusion criteria. The majority (83.2%) of respondents were medical practitioners (MPs). Overall, most (73.5%) respondents agreed that C19VPs are a good idea. Older respondents agreed more strongly than younger respondents (medians 18 and 17, respectively, p = 0.001), and respondents in private practice agreed more strongly than those in state practice (medians 18 and 16, respectively, p = 0.042). The median response was neutral (3) in response to the ethics of C19VPs considering variations in vaccine access and tending towards disagreement (2.5) in disadvantaging poorer people. Most respondents disagreed that vaccine hesitancy would make C19VPs unethical, and responses from provinces with the highest vaccination proportions disagreed more than others with lower vaccination proportion (median 2 compared with 3, p < 0.001). There was uncertainty about the feasibility of C19VPs in SA, with older HCWs, non-students, senior MPs and those who thought C19VPs are a good idea being more likely to consider them feasible. Conclusion: The perspectives of HCWs, mainly MPs, about C19VPs in SA were obtained. Further research should focus on vaccine hesitancy and its factors in HCWs and the effect of C19VPs on restrictions, reduction in transmission and benefits on economies and mental health. Contribution: To the authors' knowledge, this is the first survey data published on the perspectives of South African HCWs on C19VPs in the country. Healthcare workers are trusted influencers of vaccination decisions, and their opinion on vaccination certificates may also influence the South African public's perception and acceptance thereof.

Influence of suicidality on adult perceptions of COVID-19 risk and guideline adherence.

BACKGROUND: Suicide rates have been increasing for decades, and the challenges of a global pandemic seem to have worsened suicide risk factors. The relationship between suicidality, COVID-19 risk perceptions, and guideline adherence was examined to inform potential barriers to the implementation of behavioral interventions aimed at preventing future pandemics. METHODS: A national sample of 159 MTurk participants (Mage = 37.64 years, SD = 11.92; 48.4% female) completed an online survey containing the following: demographics, Suicidal Ideation Attributes Scale, Broadly Applicable Measure of Risk Perception of COVID-19, and Adherence to COVID-19 Guidelines and Perceived Risk Scale. RESULTS: Multiple linear regressions assessed how suicidality related to perceived risk subscales and each adherence indicator while controlling for biological sex, age, and essential worker status. Over 25% of participants reported suicidality over the past month, and 19% were at high risk of suicidal behavior. Greater suicidality was associated with lower general COVID-19 risk perceptions (ß = -0.326, p < .001), decreased handwashing (ß = -0.423, p < .001), lower likelihood of planning to self-quarantine if infected with COVID-19 (ß = -0.400, p < .001), less social distancing (ß = -0.457, p < .001), and increased attendance of large gatherings (ß = 0.405, p < .001). LIMITATIONS: Temporal relationships were unable to be assessed due to the cross-sectional nature of the data used. The low internal reliability of the risk probability subscale precluded its inclusion in analyses. CONCLUSION: Given suicidality's associations with decreased risk perceptions and low adherence, it may present as a barrier to the sustained behavior change that will be necessary in preventing the occurrence of future pandemics.

ACE2 is necessary for SARS-CoV-2 infection and sensing by macrophages but not sufficient for productive viral replication (preprint)

Macrophages are a major source of pro-inflammatory cytokines in COVID-19. How macrophages sense the causative virus, SARS-CoV-2, to drive cytokine release is, however, unclear. Here, we show that human macrophages do not directly sense and respond to infectious SARS-CoV-2 virions because they lack sufficient ACE2 expression to support virus entry and replication. Over-expression of ACE2 in human macrophages permits SARS-CoV-2 entry and early-stage replication and facilitates macrophage pro-inflammatory and anti-viral responses. ACE2 over-expression does not, however, permit the release of newly synthesised virions from SARS-CoV-2-infected macrophages, consistent with abortive replication. Release of new, infectious SARS-CoV-2 virions from ACE2 over-expressing macrophages only occurred if anti-viral mediator induction was also blocked, indicating that macrophages restrict SARS-CoV-2 infection at two stages of the viral life cycle. These findings resolve the current controversy over macrophage-SARS-CoV-2 interactions and identify a signalling circuit that directly links macrophage recognition of SARS-CoV-2 to restriction of viral replication.

Endothelial cells are not productively infected by SARS-CoV-2.

OBJECTIVES: Thrombotic and microvascular complications are frequently seen in deceased COVID-19 patients. However, whether this is caused by direct viral infection of the endothelium or inflammation-induced endothelial activation remains highly contentious. METHODS: Here, we use patient autopsy samples, primary human endothelial cells and an in vitro model of the pulmonary epithelial-endothelial cell barrier. RESULTS: We show that primary human endothelial cells express very low levels of the SARS-CoV-2 receptor ACE2 and the protease TMPRSS2, which blocks their capacity for productive viral infection, and limits their capacity to produce infectious virus. Accordingly, endothelial cells can only be infected when they overexpress ACE2, or are exposed to very high concentrations of SARS-CoV-2. We also show that SARS-CoV-2 does not infect endothelial cells in 3D vessels under flow conditions. We further demonstrate that in a co-culture model endothelial cells are not infected with SARS-CoV-2. Endothelial cells do however sense and respond to infection in the adjacent epithelial cells, increasing ICAM-1 expression and releasing pro-inflammatory cytokines. CONCLUSIONS: Taken together, these data suggest that in vivo, endothelial cells are unlikely to be infected with SARS-CoV-2 and that infection may only occur if the adjacent pulmonary epithelium is denuded (basolateral infection) or a high viral load is present in the blood (apical infection). In such a scenario, whilst SARS-CoV-2 infection of the endothelium can occur, it does not contribute to viral amplification. However, endothelial cells may still play a key role in SARS-CoV-2 pathogenesis by sensing adjacent infection and mounting a pro-inflammatory response to SARS-CoV-2.

Efficacy of a fully remote primary lecture series at an academic hematology and oncology fellowship program

Background: 615 fellows began training in American combined hematology/oncology fellowship programs in July 2020. These new fellows face a steep learning curve. The coronavirus pandemic has significantly affected how we learn, with programs having to convert most collective learning to a completely virtual format. Research on the efficacy of introductory lecture series in academic hematology/oncology programs is limited especially regarding virtual formats. We introduced a virtual introductory lecture series with the goal of increasing the clinical confidence and knowledge base of first- year fellows. Methods: A once weekly remotelydelivered two-hour primer series was designed with lectures given by both third-year fellows and faculty from July-August 2020. Fellows were asked to complete pre & post-test evaluations of each lecture. Evaluations included a combination of knowledge-based questions & self-reported confidence assessment. Results:14 fellows were assigned pre- and post-tests in the study. 1 fellow was excluded due to lack of participation. A total of 123 paired pre and post-tests were compared. Data analysis was performed with SPSS v 24.0 using the paired samples t-test. Pre and post-tests were graded on a scale of 0-100. The pre to post mean difference compares the mean test result of the post tests to that of the corresponding pretests. Questions were divided into 2 groups. The 1st group tested the fellow's medical knowledge regarding the pathology while the 2nd group tested the comfort in the management, diagnosis and treatment. In the statistical analysis, these questions were defined as 'Knowledge' and 'Comfort' accordingly, the sum as 'Complete'. A statistically significant improvement in post-test knowledge for fellows of all years was noted with a pre to post test mean difference of 12.52, P <.0001. The difference was more pronounced among 1st year fellows with a pre to post test mean difference of 16.84, P <.0001. A similar improvement was seen for the comfort in management questions. The post-test comfort pre to post test mean difference was 10.48, P <.0001 for fellows of all years and 6.70, P <.0001 for first year fellows. Conclusions: A remotely-delivered introductory lecture series for fellows in a hematology/oncology training program increases both clinical knowledge and clinical confidence in fellows of all years of training.

Pediatric nasal epithelial cells are less permissive to SARS-CoV-2 replication compared to adult cells (preprint)

Rationale: Young children (typically those <10 years old) are less susceptible to SARS-CoV-2 infection and symptoms compared to adults. However, the mechanisms that underlie these age-dependent differences remain to be determined and could inform future therapeutics for adults. Objective: To contrast the infection dynamics of SARS-CoV-2 in primary nasal epithelial cells from adults and children. Methods: Viral replication was quantified by plaque assay. The cellular transcriptome of infected and uninfected cells was assessed by RNA-seq. ACE2 and TMPRSS2 protein expression were quantified by Western Blot Measurements and Main Results: We report significantly higher SARS-CoV-2 replication in adult compared to pediatric nasal epithelial cells. This was restricted to SARS-CoV-2 infection, as the same phenomenon was not observed with influenza virus infection. The differentiational SARS-CoV-2 replication dynamics were associated with an elevated type I and III interferon response, and a more pronounced inflammatory response in pediatric cells. No significant difference between the two age groups was observed in the protein levels of ACE2 and TMPRSS2. Conclusions: Our data suggest that the innate immune response of pediatric nasal epithelial cells, and not differential receptor expression, may contribute to the reported reduced SARS-COV-2 infection and symptoms reported amongst children.

Epidemiology of COVID-19 in Mexico: Symptomatic profiles and presymptomatic people.

OBJECTIVES: The COVID-19 diagnosis is difficult and ambiguous due to nonspecific symptoms. Further, data from Mexico arehospitable population-based without signs and symptoms information. Thus, this work aims to provide epidemiology information about the burden of COVID-19 in Mexican outpatients and to identify symptomatic COVID-19 profiles that could help in the early diagnosis of the disease. METHODS: From June to September, epidemiological, clinical, and demographic data of 482,413 individuals diagnosed by RT-PCR test for SARS-CoV-2 in Salud Digna clinics were collected. RESULTS: We observed a 41% incidence of SARS-CoV-2 infections with a mean age of 36 years and with young adults (20-40 years) being the most affected. Among occupations, delivery persons (OR 1.38) or informal traders (OR 1.33) had a higher risk of COVID-19. Moreover, 13% of SARS-CoV-2 infections were in presymptomatic patients. Finally, we identified three different symptomatic profiles (common, respiratory, and gastrointestinal) associated with COVID-19. CONCLUSION: The incidence of SARS-CoV-2 was high among outpatients with a significant proportion of presymptomatic carriers, and thus it is necessary to increase testing and continue SARS-CoV-2 surveillance with a better description of signs and symptoms; in this regard, we identified three symptomatic profiles that could help in the diagnosis of COVID-19.

Obesity and SARS-CoV-2: A population to safeguard.

Evidence has lately emerged regarding an increased risk of SARS-CoV-2 with worse prognosis in patients with obesity, especially among the young. Weight excess is a well-established respiratory disease risk factor, and the newly reported correlation is therefore unsurprising. The underlying pathophysiology is likely multi-stranded, ranging from complement system hyperactivation, increased Interleukin-6 secretion, chronic inflammation, presence of comorbidities such as diabetes and hypertension, and a possible local, detrimental effect within the lung. Further understanding the link between obesity and SARS-CoV-2 is crucial, as this could aid proper tailoring of immunomodulatory treatments, together with improving stratification among those possibly requiring critical care.