Therapeutic Vitamin D Supplementation Following COVID-19 Diagnosis: Where Do We Stand?—A Systematic Review

Lessons Learned From Clinical Trials of Immunotherapeutics for COVID-19

The COVID-19 pandemic caused by the SARS-CoV-2 virus was arguably one of the worst public health disasters of the last 100 years. As many infectious disease experts were focused on influenza, MERS, ZIKA, or Ebola as potential pandemic-causing agents, SARS-CoV-2 appeared to come from nowhere and spread rapidly. As with any zoonotic agent, the initial pathogen was able to transmit to a new host (humans), but it was poorly adapted to the immune environment of the new host and resulted in a maladapted immune response. As the host-pathogen interaction evolved, subsequent variants of SARS-CoV-2 became less pathogenic and acquired immunity in the host provided protection, at least partial protection, to new variants. As the host-pathogen interaction has changed since the beginning of the pandemic, it is possible the clinical results discussed here may not be applicable today as they were at the start of the pandemic. With this caveat in mind, we present an overview of the immune response of severe COVID-19 from a clinical research perspective and examine clinical trials utilizing immunomodulating agents to further elucidate the importance of hyperinflammation as a factor contributing to severe COVID-19 disease.

The effect of macronutrient and micronutrient supplements on COVID-19: an umbrella review

BACKGROUND AND AIMS

A healthy diet play an important role in the prevention and even treatment of various diseases. Proper nutrition plays an important role in boosting of immune system. These include the consumption of macronutrients such as proteins, lipids, carbohydrates, and also micronutrients including vitamins. Here, we aimed to systematically review the effects of macronutrients and micronutrients on the prevention and treatment of COVID-19.

METHODS

We searched the databases of PubMed, Scopus, Embase, and Web of Science on December 23, 2023. The records were downloaded into an EndNote file, the duplicates were removed, and the studies underwent a two-phase screening process based on their title/abstracts and full texts. The included articles were screened and underwent inclusion and exclusion criteria. We included the English systematic reviews and meta-analyses that concurred with the aim of our study. The selected articles were assessed by Cochrane's Risk of Bias in Systematic Reviews for the quality check. The data of the eligible studies were extracted in a pre-designed word table and were used for the qualitative synthesis.

RESULTS

A total of 28 reviews were included in this study. Most studies have shown that micronutrients are effective in morbidity and mortality controlling in viral respiratory infections such as COVID-19 but some studies have shown that micronutrients are sometimes not effective in controlling severity. On the other hand, calcifediol was by far the most successful agent in reducing intensive care needs and mortality between studies.

CONCLUSION

Individuals without malnutrition had a reduced risk of SARS-CoV-2 infection and severe disease. The administration of Vitamin D is effective in reducing the morbidity and mortality of COVID-19 patients. Patients with vitamin D deficiency were more prone to experience severe infection, and they were at higher risk of morbidities and mortality. Other micronutrients such as Vitamin A, Vitamin B, and Zinc also showed some benefits in patients with COVID-19. Vitamin C showed no efficacy in COVID-19 management even in intravenous form or in high doses.

The association between vitamin D intake with inflammatory and biochemical indices and mortality in critically ill patients with COVID-19: A case-control study

BACKGROUND

The coronavirus disease-2019 (COVID-19) has become a worldwide health issue with widespread hospitalization and dependence on the intensive care unit (ICU). Vitamin D has a key role in modulating immune cells and modulating the inflammatory responses. This study aimed to investigate the association of vitamin D supplementation with inflammatory, biochemical, and mortality indices in critically ill patients with COVID-19.

METHODS

This case-control study was conducted on critically ill COVID-19 patients hospitalized in the ICU including the survived >30 day patients as the case group and dead patients as the control group. The status of vitamin D supplementation and inflammatory and biochemical indices of the patients were retrieved from the medical records. Logistic regression method was used to assess the association between 30 days survival and vitamin D supplement intake.

RESULTS

Compared to the group of COVID-19 patients who died in <30 day, the survived patients had a lower eosinophile level (2.2 ± 0.5 vs. 6 ± 0.0, p < .001) and higher vitamin D supplementation duration (9 ± 4.4 vs. 3.3 ± 1.9 day, p = .001). Vitamin D supplementation had a positive association with survival in COVID-19 patients (OR: 1.98, 95% CI: 1.15-3.40, p < .05). The association remained significant after adjustments fot age, sex, underlying diseases, and smoking.

CONCLUSION

Vitamin D supplementation in critically ill patients with COVID-19 has the potential to increase survivability within the first 30 days of hospitalization.

Cutting-Edge Approaches in Respiratory and Critical Care Medicine

The COVID-19 pandemic has affected health care across the world, with respiratory and critical care medicine being affected the most [...].

Vitamin D deficiency in British South Asians, a persistent but avoidable problem associated with many health risks (including rickets, T2DM, CVD, COVID-19 and pregnancy complications): the case for correcting this deficiency

High vitamin D deficiency rates, with rickets and osteomalacia, have been common in South Asians (SAs) arriving in Britain since the 1950s with preventable infant deaths from hypocalcaemic status-epilepticus and cardiomyopathy. Vitamin D deficiency increases common SA disorders (type 2 diabetes and cardiovascular disease), recent trials and non-linear Mendelian randomisation studies having shown deficiency to be causal for both disorders. Ethnic minority, obesity, diabetes and social deprivation are recognised COVID-19 risk factors, but vitamin D deficiency is not, despite convincing mechanistic evidence of it. Adjusting analyses for obesity/ethnicity abolishes vitamin D deficiency in COVID-19 risk prediction, but both factors lower serum 25(OH)D specifically. Social deprivation inadequately explains increased ethnic minority COVID-19 risks. SA vitamin D deficiency remains uncorrected after 70 years, official bodies using 'education', 'assimilation' and 'diet' as 'proxies' for ethnic differences and increasing pressures to assimilate. Meanwhile, English rickets was abolished from ~1940 by free 'welfare foods' (meat, milk, eggs, cod liver oil), for all pregnant/nursing mothers and young children (<5 years old). Cod liver oil was withdrawn from antenatal clinics in 1994 (for excessive vitamin A teratogenicity), without alternative provision. The take-up of the 2006 'Healthy-Start' scheme of food-vouchers for low-income families with young children (<3 years old) has been poor, being inaccessible and poorly publicised. COVID-19 pandemic advice for UK adults in 'lockdown' was '400 IU vitamin D/day', inadequate for correcting the deficiency seen winter/summer at 17.5%/5.9% in White, 38.5%/30% in Black and 57.2%/50.8% in SA people in representative UK Biobank subjects when recruited ~14 years ago and remaining similar in 2018. Vitamin D inadequacy worsens many non-skeletal health risks. Not providing vitamin D for preventing SA rickets and osteomalacia continues to be unacceptable, as deficiency-related health risks increase ethnic health disparities, while abolishing vitamin D deficiency would be easier and more cost-effective than correcting any other factor worsening ethnic minority health in Britain.

Vitamin D status and severity of COVID-19

We explored the association between COVID-19 severity and vitamin D status using information from Danish nation-wide health registers, the COVID-19 surveillance database and stored blood samples from the national biobank. 25-hydroxyvitamin D (25(OH)D) was measured using tandem mass spectroscopy. The association between 25(OH)D levels and COVID-19 severity, classified hierarchical as non-hospitalized, hospitalized but not admitted to an intensive care unit (ICU), admitted to ICU, and death, was evaluated by proportional odds ratios (POR) assuming proportionality between the four degrees of severity. Among 447 adults tested SARS-CoV-2 positive in the spring of 2020, low levels of 25(OH)D were associated with a higher risk of severe COVID-19. Thus, odds of experiencing more severe COVID-19 among individuals with insufficient (25 to < 50 nmol/L) and sufficient (≥ 50 nmol/L) 25(OH)D levels were approximately 50% of that among individuals with deficient levels (< 25 nmol/L) (POR = 0.49 (95% CI 0.25-0.94), POR = 0.51 (95% CI 0.27-0.96), respectively). Dividing sufficient vitamin D levels into 50 to < 75 nmol/L and ≥ 75 nmol/L revealed no additional beneficial effect of higher 25(OH)D levels. In this observational study, low levels of 25(OH)D were associated with a higher risk of severe COVID-19. A possible therapeutic role of vitamin D should be evaluated in well-designed interventional studies.

Rapidly Increasing Serum 25(OH)D Boosts the Immune System, against Infections-Sepsis and COVID-19

Vitamin D deficiency is a global public health problem, a pandemic that commonly affects the elderly and those with comorbidities such as obesity, diabetes, hypertension, respiratory disorders, recurrent infections, immune deficiency, and malignancies, as well as ethnic minorities living in temperate countries. The same groups were worst affected by COVID-19. Since vitamin D deficiency weakens the immune system, it increases the risk of infections, complications, and deaths, such as from sepsis and COVID-19. Deficiency can be remedied cost-effectively through targeted food fortification, supplementation, and/or daily safe sun exposure. Its endocrine functions are limited to mineral metabolism, musculoskeletal systems, specific cell membrane interactions, and parathyroid gland functions. Except for the rapid, endocrine, and cell membrane-based non-genomic functions, all other biological and physiological activities of vitamin D depend on the adequate intracellular synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells via the genome. Calcitriol mediates autocrine (intracrine) and paracrine signalling in immune cells, which provides broader, protective immune functions crucial to overcoming infections. The synthesis of 1,25(OH)2D (calcitriol) in peripheral target cells is dependent on diffusion and endocytosis of D3 and 25(OH)D from the circulation into them, which requires maintenance of serum 25(OH)D concentration above 50 ng/mL. Therefore, in acute infections such as sepsis and respiratory infections like COVID-19, it is necessary to rapidly provide its precursors, D3 and 25(OH)D, through the circulation to generate adequate intracellular calcitriol. Immune defence is one of the crucial non-hormonal functions of vitamin D. A single oral (bolus) dose or divided upfront loading doses between 100,000 and 500,000 IU, using 50,000 IU vitamin D3 increase the serum 25(OH)D concentrations to a therapeutic level of above 50 ng/mL that lasts between two to three months. This takes three to five days to raise serum 25(OH)D. In contrast, a single oral dose of calcifediol (0.014 mg/kg body weight) can generate the needed 25(OH)D concentration within four hours. Considering both D3 and 25(OH)D enter immune cells for generating calcitriol, using the combination of D3 (medium-term) and calcifediol (immediate) is cost-effective and leads to the best clinical outcome. To maximise protection against infections, particularly to reduce COVID-19-associated complications and deaths, healthcare workers should advise patients on safe sun exposure, adequate vitamin D supplementation and balanced diets containing zinc, magnesium, and other micronutrients to support the immune system. Meanwhile, governments, the World Health Organisation, the Centers for Disease Control, and governments should consider similar recommendations to physicians and the public, change the outdated vitamin D and other micronutrient recommendations directed to their population, and organise targetted food fortification programs for the vulnerable groups. This article discusses a rational approach to maintaining a sustained serum 25(OH)D concentration above 50 ng/mL, necessary to attain a robust immune system for overcoming infections. Such would cost-effectively improve the population’s health and reduce healthcare costs. It also describes three cost-effective, straightforward protocols for achieving and sustaining therapeutic serum 25(OH)D concentrations above 50 ng/mL (>125 nmol/L) to keep the population healthy, reduce absenteeism, improve productivity, and lower healthcare costs.