Role of Vitamin D in Risk Reduction of COVID-19: A Narrative Review

Vitamin D Deficiency and Comorbidities as Risk Factors of COVID-19 Infection: A Systematic Review and Meta-analysis

OBJECTIVES

Extensive evidence links low vitamin D status and comorbidities with coronavirus disease 2019 (COVID-19) outcomes, but the results of published studies are contradictory. Therefore, we investigated the association of lower levels of vitamin D and comorbidities with the risk of COVID-19 infection.

METHODS

We searched MEDLINE (via PubMed), Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for articles published until August 20, 2021. Sixteen eligible studies were identified (386 631 patients, of whom 181 114 were male). We included observational cohort and case-control studies that evaluated serum levels of vitamin D in COVID-19-positive and COVID-19-negative patients. Mean differences (MDs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Significantly lower vitamin D levels were found in COVID-19-positive patients (MD, -1.70; 95% CI, -2.74 to -0.66; p=0.001), but with variation by study design (case-control: -4.04; 95% CI, -5.98 to -2.10; p<0.001; cohort: -0.39; 95% CI, -1.62 to 0.84; p=0.538). This relationship was more prominent in female patients (MD, -2.18; 95% CI, -4.08 to -0.28; p=0.024) than in male patients (MD, -1.74; 95% CI, -3.79 to 0.31; p=0.096). Male patients showed higher odds of having low vitamin D levels (odds ratio [OR], 2.09; 95% CI, 1.38 to 3.17; p<0.001) than female patients (OR, 1.17; 95% CI, 0.74 to 1.86; p=0.477). Comorbidities showed inconsistent, but generally non-significant, associations with COVID-19 infection.

CONCLUSIONS

Low serum vitamin-D levels were significantly associated with the risk of COVID-19 infection. This relationship was stronger in female than in male COVID-19 patients. Limited evidence was found for the relationships between comorbidities and COVID-19 infection, warranting large population-based studies to clarify these associations.

Current advancements and future prospects of COVID-19 vaccines and therapeutics: a narrative review

Coronavirus disease 2019 (COVID-19) has made a global impact on the daily lives of humanity, devastating health systems, and cataclysmically affecting the world's economy. Currently, the Standard Public Health Protective practices consist of but are not limited to wearing masks, social distancing, isolating sick and exposed people, and contact tracing. Scientists around the globe undertook swift scientific efforts to develop safe and effective therapeutics and vaccines to combat COVID-19. Presently, as of mid-March 2022, 57.05% of the world population have been fully vaccinated, and 65.3% of the United States of America's (USA) total population have been fully vaccinated while 76.7% have received at least one dose of the vaccine. This article explores the various vaccines created through modern science and technology, including their safety, efficacy, and mechanism of action. Although the vaccines produced are up to 95.0% efficacious, their efficacy wanes over time, underscoring the need for booster doses. Also, vaccination has not been able to prevent "breakthrough" infections. The limitations of the SARS-CoV-2 vaccines indicate that further measures are required to ensure a firm control of the COVID-19 pandemic. Therefore, the Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for the use of certain therapeutic agents because they have shown remarkable clinical outcomes. Several therapeutic agents for the treatment of mild-to-moderate COVID-19 include Gilead's remdesivir, Regeneron's casirivimab and imdevimab combination, Eli Lilly's baricitinib and remdesivir combination, Pfizer's co-packaged nirmatrelvir tablets and ritonavir tablets, and Merck's molnupiravir capsules. Hence concerted efforts in early and accurate diagnosis, education on the COVID-19 virulence, transmission and preventive measures, global vaccination, and therapeutic agents could bring this COVID-19 pandemic under control across the globe.