Commentary: COVID-19 and obesity pandemics converge into a syndemic requiring urgent and multidisciplinary action

Phenotypic flexibility in nutrition research to quantify human variability: building the bridge to personalised nutrition

Phenotypic flexibility is a methodology that accurately assesses health in terms of mechanistic understanding of the interrelationship of multiple metabolic and physiological processes. This starts from the perspective that a healthy person is better able to cope with changes in environmental stressors that affect homeostasis compared to people with a compromised health state. The term 'phenotypic flexibility' expresses the cumulative ability of overarching physiological processes to return to homeostatic levels after short-term perturbations. The concept of phenotypic flexibility to define biomarkers for nutrition-related health was introduced in 2009 in the area of health optimisation and prevention and delay of non-communicable disease. The core approach consists of the combination of imposing a challenge test to the body followed by time-resolved analysis of multiple biomarkers. This new approach may better facilitate nutritional health research in intervention studies since it may show effects on early derailed physiological markers and the biomarker response can be extended by perturbing the system, thereby making them more sensitive in detecting health effects from food and nutrition. At the same time, interindividual variation can also be extended and compressed by challenge tests, facilitating the bridge to personalised nutrition. This review will overview where the science is in this research arena and what the phenotypic flexibility potential is for the nutrition field.

Obesity as a Risk Factor of Severe Outcome of COVID-19: A Pair-Matched 1:2 Case-Control Study

BACKGROUND AND AIM

The nature of the association between obesity and poor prognosis of COVID-19 without the evaluation of other co-pathologies associated has not yet been clearly evaluated. The aim of the present pair-matched case-control study was to investigate the outcome of patients with SARS-CoV-2 infection in obese and non-obese patients matched considering gender, age, number of comorbidities, and Charlson Comorbidity Index.

METHODS

All the adults hospitalized for SARS-CoV-2 infection and with BMI ≥ 30 kg/m² were included (Cases). For each Case, two patients with BMI < 30 kg/m² pair matched for gender, age (±5 years), number of comorbidities (excluding obesity), and Charlson Comorbidity Index (±1) were enrolled (Controls).

RESULTS

Of the 1282 patients with SARS-CoV-2 infection followed during the study period, 141 patients with obesity and 282 patients without were enrolled in the case and control groups, respectively. Considering matching variables, there was no statistical difference between the two groups. Patients in the Control group developed more frequently a mild-moderate disease (67% vs. 46.1%, respectively), whereas obese patients were more prone to need intensive care treatment (41.8% vs. 26.6%, respectively; p = 0.001). Moreover, the prevalence of death during hospitalization was higher in the Case group than in the Control group (12.1% vs. 6.4%, p = 0.046).

DISCUSSION

We confirmed an association between obesity and severe outcome of patients with COVID-19, also considering other factors associated with a severe outcome of COVID-19. Thus, in the case of SARS-CoV-2 infection, the subjects with BMI ≥ 30 kg/m² should be evaluated for early antiviral treatment to avoid the development of a severe course.

Inclusion of Social and Structural Determinants of Health to Advance Understanding of their Influence on the Biology of Chronic Disease

Social Determinants of Health (SDOH) consider social, political, and economic factors that contribute to health disparities in patients and populations. The most common health-related SDOH exposures are food and housing insecurity, financial instability, transportation needs, low levels of education, and psychosocial stress. These domains describe risks that can impact health outcomes more than health care. Epidemiologic and translational research demonstrates that SDOH factors represent exposures that predict harm and impact the health of individuals. International and national guidelines urge health professionals to address SDOH in clinical practice and public health. The further implementation of these recommendations into basic and translational research, however, is lagging. Herein, we consider a precision health framework to describe how SDOH contributes to the exposome and exacerbates physiologic pathways that lead to chronic disease. SDOH factors are associated with various forms of stressors that impact physiological processes through epigenetic, inflammatory, and redox regulation. Many SDOH exposures may add to or potentiate the pathologic effects of additional environmental exposures. This overview aims to inform basic life science and translational researchers about SDOH exposures that can confound associations between classic biomedical determinants of disease and health outcomes. To advance the study of toxicology through either qualitative or quantitative assessment of exposures to chemical and biological substances, a more complete environmental evaluation should include SDOH exposures. We discuss common approaches to measure SDOH factors at individual and population levels and review the associations between SDOH risk factors and physiologic mechanisms that influence chronic disease. We provide clinical and policy-based motivation to encourage researchers to consider the impact of SDOH exposures on study results and data interpretation. With valid measures of SDOH factors incorporated into study design and analyses, future toxicological research may contribute to an evidence base that can better inform prevention and treatment options, to improve equitable clinical care and population health. © 2022 Wiley Periodicals LLC.

Obesity, Hypovitaminosis D, and COVID-19: the Bermuda Triangle in Public Health

PURPOSE OF REVIEW

The COVID-19 pandemic has challenged public health to a significant extent by markedly increasing morbidity and mortality. Evidence suggests that obesity and hypovitaminosis D constitute important risk factors for SARS-CoV-2 infection, severity of disease, and poor outcomes. Due to their high prevalence globally, obesity and hypovitaminosis D are considered pandemics. This review presents current epidemiologic and genetic data linking obesity, hypovitaminosis D, and COVID-19, highlighting the importance of the convergence of three pandemics and their impact on public health. We also briefly summarize potential mechanisms that could explain these links.

RECENT FINDINGS

Epidemiologic data have shown that obesity is an independent risk factor for COVID-19, severe disease and death, and genetic evidence has suggested a causal association between obesity-related traits and COVID-19 susceptibility and severity. Additionally, obesity is independently associated with hypovitaminosis D, which is highly prevalent in subjects with obesity. Hypovitaminosis D is independently associated with a higher risk for COVID-19, severity, hospitalization, infectious complications, acute respiratory distress syndrome, and poor outcomes. However, genome-wide association studies have not revealed any causal association between vitamin D levels and the risk for COVID-19, while there is no robust evidence for a beneficial role of vitamin D supplementation in the prevention and treatment of COVID-19. In the context of the ongoing COVID-19 pandemic, the epidemiologic impact of obesity and hypovitaminosis D is emphasized. Efforts to increase public awareness and reinforce preventive and therapeutic measures against obesity and hypovitaminosis D are strongly required.

Role of diabetes mellitus in the clinical course and outcome of SARS-CoV-2 infected patients

PURPOSE

Our aim was to study patients with diabetes mellitus and SARS-CoV-2-infection diagnosed during the first pandemic wave in Greece.

METHODS

Cases were retrieved from the national database of SARS-CoV-2 infections.

RESULTS

We studied 2624 SARS-CoV-2 infected cases, including 157 with diabetes. Patients with diabetes more often had other comorbidities (68.8 vs. 24.1%; p-value < 0.001). Among patients with diabetes, 149 (94.9%) developed symptomatic disease (COVID-19) compared to 1817 patients (73.7%) without diabetes (p-value < 0.001). A total of 126 patients with diabetes and COVID-19 were hospitalized and 41 died (27.5% case-fatality rate compared to 7.5% among patients without diabetes; p-value < 0.001). Patients with diabetes more often were hospitalized, developed complications, were admitted to the intensive care unit (ICU), received invasive mechanical ventilation, and died compared to patients without diabetes (p-values < 0.001 to 0.002 for all comparisons). Multivariate logistic regression analyses revealed that diabetes, having other comorbidities, and older age were significantly associated with higher risk for hospitalization, ICU admission, invasive mechanical ventilation, and death, and that obesity was significantly associated with higher risk for hospitalization, ICU admission, and mechanical intubation, while female gender protected against these outcomes.

CONCLUSION

COVID-19 is associated with increased rates of serious morbidity and adverse outcome in patients with diabetes and represents a severe illness for them.

Weight stigma in the COVID-19 pandemic: a scoping review

BACKGROUND

Weight stigma is a phenomenon associated with adverse behavioural and psychological consequences. Although experts suggest that its increase during the COVID-19 pandemic may be associated with worse health outcomes for people with obesity, a thorough analysis of the main findings and gaps is still needed when relating to this subject.

OBJECTIVE

We aim to answer three questions: (1) How does weight stigma manifest in the COVID-19 pandemic? (2) How can weight stigma affect people with overweight or obesity in times of COVID-19? (3) What are the perceptions and experiences of weight stigma during the pandemic in individuals who experience overweight or obesity?

METHODS

We conducted a scoping review of studies addressing weight stigma and the COVID-19 pandemic in electronic databases (Medline/PubMed, CINAHL, Embase, PsycInfo, BVS/Lilacs, Scopus, Web of Science, Google Scholar, and OpenGrey) published until 10th August 2021. All relevant studies were reviewed in full by two researchers. In addition, a narrative synthesis of the data was performed.

RESULTS

The results included 35 studies out of 8,090 records and identified 13 original research publications, 14 text and opinion papers, and 6 narrative reviews. The results revealed the presence of weight stigma in the media, healthcare settings, interpersonal relationships, and public campaigns during the COVID-19 pandemic. The evidence of increasing weight stigma in the COVID-19 outbreak is limited, though. Many weight discrimination consequences were described during this time, such as impairment in accessing healthcare, worst COVID-19 outcomes, and maladaptive eating. However, only maladaptive behaviours and decline in mental health outcomes were demonstrated empirically in all age groups. This effect occurred regardless of body mass index, but people with high body weight were more likely to experience weight stigma. For some people with obesity, weight stigma in the pandemic has made activities of daily routine difficult.

CONCLUSIONS

The results suggest that weight stigma in the COVID-19 pandemic occurs in several settings; moreover, although weight discrimination impacts mental health, whether before or during the pandemic, this influence between the pandemic and pre-pandemic scenario is still unclear. Therefore, more research is required in this field while the pandemic lasts, especially with people with obesity. Overall, people with overweight or obesity are more vulnerable to weight stigma than individuals without overweight. In addition, weight stigma refers to discrimination or prejudice based on a person's weight and relates to several consequences, for instance, poor healthcare treatment and mental health problems. In the COVID-19 outbreak, these weight stigma effects tend to become even more critical because they may be associated with unfavourable COVID-19 outcomes and eating disorder risks. Thus, it is crucial to investigate how weight stigma occurs during the pandemic and its impact on health, mainly for the most affected people. We investigated 35 studies published between 2019 and 2021 to map and explore how weight stigma was manifested and the related consequences for people with overweight or obesity in the COVID-19 pandemic. Only about a third of them were quantitative or qualitative, limiting the evidence of weight stigma in the COVID-19 context. The available evidence suggests that weight stigma manifests in several settings such as media, healthcare, public campaigns, and is more common in people with excess weight. However, weight discrimination experiences before or during the pandemic were associated with adverse psychological and behavioural consequences across all age groups, regardless of body weight. For some people with obesity, for instance, weight stigma made it difficult to accomplish their activities of daily routine. Nevertheless, it remains unclear whether weight stigma has increased in the pandemic, thus, more studies are required, especially about people with overweight or obesity.

Planning for health equity in the crossfire between science and policy

The persistence of health inequalities means that many public health professionals face an ongoing task to develop and update policies to tackle them. However, although the inequalities might be unchanged, the political priorities in the many policy areas involved are changing and the ambition to reduce the health divide is constantly facing strong forces pushing in the opposite direction. Recent proposals to re-think health inequalities need to be treated with caution because they are disconnected from what is needed for policy-making in this area. From our experience of 35 years in developing strategies to tackle health inequalities, we still see many entry points with space for local and national improvements, but it is crucial to ask the right questions. The aim of this Commentary is to present a new framework of eight questions that might provide a helpful structure for the necessary dialogue between researchers and policy-makers. Even if answers are not yet available for all of them, we believe that discussing them for a specific population in a specific political context will be fruitful to inform policy on the ground.

Rethinking COVID-19 and Beyond: Prevention, Remedies, and Recovery

In a relatively short timeframe, millions of deaths and illnesses associated with COVID-19 have been reported, accompanied by substantial economic losses, and overall, negatively impacting society. This experience should serve as a wakeup call to those in public health and healthcare, along with politicians and citizens: COVID-19 is considered a predictable and preventable disaster. While various reactive responses to address the pandemic were implemented, some with adverse effects, proactive measures in the years before COVID-19 were neglected. Predominately this involved the development of a preventable overfat pandemic, which played a key role in both rising rates of chronic disease, the comorbidities that increase the risk for COVID-19, along with associated inflammation and malnutrition. This increased the risk of infection in billions of people worldwide, which, in essence, primed society for high rates of COVID-19 infection. Excess body fat evolves primarily from poor nutrition, particularly the overconsumption of sugar and other refined carbohydrates, which replace the vital nutrients needed for optimal immune function. Sugar and refined carbohydrates must be considered the new tobacco, as these foods are also devoid of nutrients, and underly inflammatory chronic diseases. A balanced diet of nutrient-dense wholefood must be emphasized to combat infectious and inflammatory diseases. Implementing proactive preventive lifestyle changes must begin now, starting with simple, safe, and inexpensive dietary modifications that can quickly lead to a healthier population.

COVID-19 pandemic impact on trajectories in cardiometabolic health, physical activity and functioning among adults from the 2006-2020 Health and Retirement Study

Background

The aim of this study was to evaluate the impact of the COVID-19 pandemic on trajectories in cardiometabolic health, physical activity, and functioning among U.S. older adults, overall and according to selected baseline sociodemographic characteristics.

Methods

We performed secondary analyses using longitudinal data on 1,372 participants from the 2006–2020 Health and Retirement Study. Pre-post COVID-19 pandemic onset was examined in relation to body mass index (BMI), number of cardiometabolic risk factors and/or chronic conditions, physical activity, Activities of Daily Living (ADL), and Instrumental Activities of Daily Living (IADL) using mixed-effects regression models and group-based trajectory models.

Results

The COVID-19 pandemic was associated with significantly increased BMI (β = 1.39, 95% confidence interval [CI]: 0.74, 2.03). Furthermore, the odds of having at least one cardiometabolic risk factor and/or chronic disease increased pre-post COVID-19 onset (odds ratio 1.16, 95% CI: 1.00, 1.36), whereas physical functioning worsened pre-post COVID-19 onset (ADL: β = 1.11, 95% CI: 0.94, 1.28; IADL: β = 0.59, 95% CI: 0.46, 0.73). The pre-post COVID-19 period (2018–2020) showed a stable group of trajectories, with low, medium and high levels of the selected health indicators. Health disparities according to sex, race/ethnicity, educational level, work status, and total wealth are highlighted.

Conclusions

The COVID-19 pandemic onset appears to worsen cardiometabolic health and physical functioning among U.S. older adults, with clusters of individuals defined by selected sociodemographic characteristics experiencing distinct trajectories pre-post COVID-19 pandemic onset.

Systematic review of the effects of pandemic confinements on body weight and their determinants

Pandemics and subsequent lifestyle restrictions such as ‘lockdowns’ may have unintended consequences, including alterations in body weight. This systematic review assesses the impact of pandemic confinement on body weight and identifies contributory factors. A comprehensive literature search was performed in seven electronic databases and in grey sources from their inception until 1 July 2020 with an update in PubMed and Scopus on 1 February 2021. In total, 2361 unique records were retrieved, of which forty-one studies were identified eligible: one case–control study, fourteen cohort and twenty-six cross-sectional studies (469, 362 total participants). The participants ranged in age from 6 to 86 years. The proportion of female participants ranged from 37 % to 100 %. Pandemic confinements were associated with weight gain in 7·2–72·4 % of participants and weight loss in 11·1–32·0 % of participants. Weight gain ranged from 0·6 (sd 1·3) to 3·0 (sd 2·4) kg, and weight loss ranged from 2·0 (sd 1·4) to 2·9 (sd 1·5) kg. Weight gain occurred predominantly in participants who were already overweight or obese. Associated factors included increased consumption of unhealthy food with changes in physical activity and altered sleep patterns. Weight loss during the pandemic was observed in individuals with previous low weight, and those who ate less and were more physically active before lockdown. Maintaining a stable weight was more difficult in populations with reduced income, particularly in individuals with lower educational attainment. The findings of this systematic review highlight the short-term effects of pandemic confinements.

Is Serotonin the Missing Link between COVID-19 Course of Severity in Patients with Diabetes and Obesity?

COVID-19 is an intriguing infectious condition with multisystemic manifestations and variable outcomes that are influenced by the concomitant presence of non-communicable diseases, such as obesity, diabetes, and cardiovascular disease, which were previously well established epidemics and therefore are considered global syndemics. Although an enormous progress towards understanding mechanisms of SARS-CoV-2 infection leading to COVID-19 has been made, there are still many areas of uncertainty to clarify. Systemic diseases are characterized by common links that allow integrating apparently unrelated disease manifestations. The authors launch the provocative hypothesis that serotonin is the putative mediator linking the lung, gut, cardiac, neurological, and other systemic manifestations that characterize severe COVID-19 in individuals with diabetes and obesity. In support of a role for serotonin in the mechanisms leading to disease severity are the similarities between acute and post-acute COVID-19 manifestations and neuroendocrine tumors presenting with carcinoid syndrome. Scientific discussion is set by highlighting the available clues that support this working hypothesis to trigger future research aimed at unravelling the molecular pathways underlying SARS-CoV-2 infection that are still far from being fully disclosed.

Diabetes and COVID-19: What 2 Years of the Pandemic Has Taught Us

As the world enters its third year of the COVID-19 pandemic, individuals with diabetes have faced particular challenges from the virus. A deleterious bidirectional relationship exists between the two disorders, with heightened inflammatory, immunologic, and cellular mechanisms leading to a more severe illness and increased morbidity and mortality. Tight glucose control, though necessary, is hampered by physical restrictions and difficulty accessing health care. Novel glucose-lowering medications may provide unique benefits in this regard. It is imperative that multi-pronged efforts be prioritized in order to reduce adverse outcomes in patients with diabetes at risk for COVID-19.

Prevention of Cardiovascular Burden in COVID-19 Patients Suffering from Familial Hypercholesterolemia: A Global Challenge

A recent meta-analysis of over 20,000 individuals showed that hospitalized COVID-19 patients with acute myocardial injury had more than fourfold higher mortality than those without such injury. Since the COVID-19 pandemic exacerbates already existing health inequalities, there is an urgent need to create measures to protect the most vulnerable patient groups, including those with a pre-existing increased risk of atherosclerotic cardiovascular disease (ASCVD). A typical example is familial hypercholesterolemia (FH), a common genetic disease affecting over 30 million individuals worldwide. If left untreated or undertreated, FH patients suffer from complications of premature ASCVD, such as acute coronary syndromes, resulting in acute myocardial injury/infarction. A recent population-based analysis provided strong evidence suggesting that COVID-19 poses an even higher risk for myocardial injury in FH patients. From the long-term preventive point of view, it is important to note that, in addition to the acutely elevated risk of myocardial injury, an elevated risk of ASCVD and its complications will persist after COVID-19. The decline in outpatient preventive care during the pandemic is likely to influence ASCVD risk and outcomes, particularly in high-risk patients, such as those with FH. This commentary aims to raise global awareness of the challenges that clinicians treating FH patients continue to face during the COVID-19 pandemic, with two low- to middle-income countries, South Africa and Brazil, serving as examples.

Understanding the Co-Epidemic of Obesity and COVID-19: Current Evidence, Comparison with Previous Epidemics, Mechanisms, and Preventive and Therapeutic Perspectives

PURPOSE OF REVIEW

A growing body of evidence suggests that obesity and increased visceral adiposity are strongly and independently linked to adverse outcomes and death due to COVID-19. This review summarizes current epidemiologic data, highlights pathogenetic mechanisms on the association between excess body weight and COVID-19, compares data from previous pandemics, discusses why COVID-19 challenges the "obesity paradox," and presents implications in prevention and treatment as well as future perspectives.

RECENT FINDINGS

Data from meta-analyses based on recent observational studies have indicated that obesity increases the risks of infection from SARS-CoV-2, severe infection and hospitalization, admission to the ICU and need of invasive mechanical ventilation (IMV), and the risk of mortality, particularly in severe obesity. The risks of IMV and mortality associated with obesity are accentuated in younger individuals (age ≤ 50 years old). The meta-inflammation in obesity intersects with and exacerbates underlying pathogenetic mechanisms in COVID-19 through the following mechanisms and factors: (i) impaired innate and adaptive immune responses; (ii) chronic inflammation and oxidative stress; (iii) endothelial dysfunction, hypercoagulability, and aberrant activation of the complement; (iv) overactivation of the renin-angiotensin-aldosterone system; (v) overexpression of the angiotensin-converting enzyme 2 receptor in the adipose tissue; (vi) associated cardiometabolic comorbidities; (vii) vitamin D deficiency; (viii) gut dysbiosis; and (ix) mechanical and psychological issues. Mechanistic and large epidemiologic studies using big data sources with omics data exploring genetic determinants of risk and disease severity as well as large randomized controlled trials (RCTs) are necessary to shed light on the pathways connecting chronic subclinical inflammation/meta-inflammation with adverse COVID-19 outcomes and establish the ideal preventive and therapeutic approaches for patients with obesity.

Familial hypercholesterolemia and COVID-19: A menacing but treatable vasculopathic condition

SARS-CoV-2 infection continues to cause increased morbidity and mortality, and due to the slow pace of vaccination COVID-19 will probably remain a global burden to health systems for a long time. Unfortunately, the necessary prevention and treatment strategies of COVID-19 have led to restriction measures that are hampering the routine care of common chronic metabolic conditions like hypercholesterolemia. It is of particular concern that during the acute phase of COVID-19, the control of pre-existing metabolic diseases tends to get worse which again increases the risk for complications and a poor outcome in these patients. A significant contributor to these complications is endothelial dysfunction which is associated with COVID-19. This Commentary will discuss the impact of COVID-19 on endothelial function particularly in patients with familial hypercholesterolemia (FH), a metabolic inherited disease known to in itself adversely affect endothelial function. There should be no hesitation to continue with statin therapy in severe hypercholesterolemic patients with COVID-19. We argue that in FH patients with COVID-19 the clinicians need even consider intensifying statin therapy as well as the addition of other lipid-lowering agents, such as proprotein convertase subtilisin/kexin type 9(PCSK9) inhibitors. In contrast to statins, the PCSK9 inhibitors lower lipoprotein(a) [Lp(a)] level, and, accordingly, these latter drugs need to be considered particularly in FH patients with an elevated level of Lp(a). This call applies to the in-hospital stay and also beyond. When considering that the vasculopathic effects of COVID-19 may persist, a long-term follow-up of individualized therapies in FH patients is warranted.

A Nutritional Counseling Program Prevents an Increase in Workers' Dietary Intake and Body Weight During the COVID-19 Pandemic

The COVID-19 pandemic caused thousands of deaths and changed lives all over the world. Daily life has also altered people's eating habits, mainly among those who stayed working at home. However, changes in the eating habits of workers who remained working during the pandemic are still unknown. The aim of this study was to evaluate the impact of the COVID-19 pandemic on the dietary habits of day and shift workers from a condominium management company, as well as to measure adherence to a nutritional counseling program and its effect on workers' food intake and body weight. One hundred and fifty-one workers (77.5% of day workers and 22.5% of shift workers) were followed up in the pre-pandemic period and during the pandemic. Data on anthropometry, food consumption, and adherence to nutritional counseling were collected during nutritional meetings, which focused on qualitative modification of food intake and control of energy consumption. The rate of adherence to the program did not differ between shifts. The pandemic significantly increased the intake of calories, macronutrients, and several micronutrients in workers of both shifts. Adherence to the nutritional counseling program had an impact on the consumption of proteins and some micronutrients, and also promoted a reduction in body weight and body mass index of workers of both shifts. Evening/night shift workers overall ate their meals later than day workers and also presented an earlier afternoon snack during the pandemic when compared with the pre-pandemic period. In conclusion, the pandemic seems to contribute to the increase in food intake of workers, regardless of the work shift. Those who joined a nutritional counseling program managed their food intake and lost weight.

Body mass index is just a number: Conflating riskiness and unhealthiness in discourse on body size

Despite the ubiquity of the body mass index (BMI) in discourse on health, there is ambiguity in its use as a biomarker of current abnormality versus future risk. This distinction is consequential for knowledge of the relationship between body size and health, as well as for individuals deemed to have abnormal and 'unhealthy' bodies. Consequently, the purposes of this review are threefold. The first is to differentiate this 'biomarker' perspective from extant critiques of BMI as a proxy for health behaviours or as the defining characteristic of obesity as a disease. The second is to highlight the shift towards treating BMI as a measure of attained unhealthiness, rather than a probabilistic indicator of risk. Finally, rather than call for the abolition of BMI, this paper argues that its continued use as 'just a number' is in keeping with the push for weight neutrality in research and practice. The review concludes by demonstrating how the riskiness and unhealthiness of body size is conflated in public health messaging on COVID-19. BMI is a marker of risk, but its use as a surrogate for COVID-19 severity equates body size with health, shaping beliefs about vulnerability and personal responsibility amid an ongoing pandemic.

A Comprehensive Review of Viral Characteristics, Transmission, Pathophysiology, Immune Response, and Management of SARS-CoV-2 and COVID-19 as a Basis for Controlling the Pandemic

COVID-19 emerged from China in December 2019 and during 2020 spread to every continent including Antarctica. The coronavirus, SARS-CoV-2, has been identified as the causative pathogen, and its spread has stretched the capacities of healthcare systems and negatively affected the global economy. This review provides an update on the virus, including the genome, the risks associated with the emergence of variants, mode of transmission, immune response, COVID-19 in children and the elderly, and advances made to contain, prevent and manage the disease. Although our knowledge of the mechanics of virus transmission and the immune response has been substantially demystified, concerns over reinfection, susceptibility of the elderly and whether asymptomatic children promote transmission remain unanswered. There are also uncertainties about the pathophysiology of COVID-19 and why there are variations in clinical presentations and why some patients suffer from long lasting symptoms-"the long haulers." To date, there are no significantly effective curative drugs for COVID-19, especially after failure of hydroxychloroquine trials to produce positive results. The RNA polymerase inhibitor, remdesivir, facilitates recovery of severely infected cases but, unlike the anti-inflammatory drug, dexamethasone, does not reduce mortality. However, vaccine development witnessed substantial progress with several being approved in countries around the globe.