Immunomodulatory Effects of Vitamin D in Respiratory Tract Infections and COVID-19 in Children

Abstract

Acute respiratory tract infections (ARTIs) are one of the main reasons that the pediatric population goes to the doctor. The connection between ARTI and vitamin D (VD) is currently debated by the medical community, and so far, there has been little agreement with regard to the ideal level of 25(OH)D concentration that would provide protection for the respiratory tract, or the effectiveness of its administration in the treatment of respiratory infections. The purpose of this literature review was to bring attention to the immunomodulatory and antiviral function of vitamin D and its relation to the respiratory system by examining the main ARTIs, including SARS-CoV-2. The latter has affected the pediatric population in different ways, from asymptomatic patients to severe forms with multisystem inflammatory syndrome in children (MIS-C). Although there are not much clinical data on the SARS-CoV-2 disease in the pediatric population worldwide, we tried to find out whether there is a connection between the severity of this disease, other ARTIs, and vitamin D supplementation. We also aimed to find out if 25OHD deficiency had an adverse effect on the evolution of the disease and the recovery period in the case of younger patients affected by COVID-19. For this literature review, the PICO framework was selected as the methodological approach. Our results demonstrated many methods by which this vitamin may lower the risk of ARTI with regard to the COVID-19 infection. Despite these significant advancements, more research is needed to support the idea that 25(OH)D concentration can influence the evolution of respiratory tract infections in children.

Exploring demographical, clinical, and dietary determinants of vitamin D deficiency among adults in Douala, Cameroon during the COVID-19 era

“…All these three findings taken together are consistent with the findings of the bulk of systematic reviews and meta-analyses of observational studies and randomized clinical trials, which outlined an increased risk of SARS–CoV–2 infection and/or complications in patients with low vitamin D levels [ 10 , 13 , 15 , [32] , [33] , [34] , [35] , [36] ], even though the link between VDD and SARS–CoV–2 associated mortality is still elusive [ 33 , 34 ]. Vitamin D plays a crucial role of immunomodulator through the improvement of components of the host’s innate and adaptive immune response and downregulation of the SARS-CoV-2 associated inflammatory cascades [ 37 , 38 ]. Several mechanisms of action through which vitamin D exerts its anti-SARS–CoV–2 effects have been proposed.…”

“…Of note, a few studies reported no or an inconsistent relationship between vitamin D deficiency and COVID–19 related infection, intensive care unit admission, length of hospital stay, ventilator support requirement, and mortality [ 12 , 13 , 17 , 18 , [42] , [43] , [44] , [45] ]. Moreover, the benefit of vitamin D supplementation is still elusive in social groups such as children [ 38 ]. Differences in design, definitions used for vitamin D deficiency, methodological quality, and populations of individual studies included in these systematic reviews and meta-analyses could explain discrepancies in conclusions.…”

Exploring the Preventive Potential of Vitamin D against Respiratory Infections in Preschool-Age Children: A Cross-Sectional Study

“…Contrary to our findings, Şişmanlar et al’s case–control study [ 30 ] found no significant correlation between vitamin D levels and the incidence or severity of lower respiratory tract infections despite a widespread prevalence of vitamin D deficiency/insufficiency among the children studied. On the contrary, Nicolae et al [ 31 ], through a literature review, highlighted the potential immunomodulatory and antiviral effects of vitamin D, suggesting that its supplementation might lower the risk of acute respiratory tract infections, including COVID-19. While Şişmanlar et al caution against assuming the direct protective role of vitamin D against such infections due to their findings, Nicolae et al advocate for the potential benefits of vitamin D in mitigating the severity of RTIs, urging further research to solidify these preliminary observations.…”

Vitamin D supply, respiratory viral infections and persistent wheezing in children: how significant is the relationship?

“…Признано, что патогенность респираторных вирусов, таких как COVID-19 или грипп, может быть связана с гиперцитокинемией или цитокиновым штормом, потенциально фатальным самовоспроизводящимся циклом воспалительных реакций [28,29]. При инфицировании вирусом гриппа отмечено снижение уровней провоспалительных «штормовых» интерлейкинов -IFN-β, TNF-α, IL-8, IL-6, RANTES в эпителиальных клетках легких в ответ на лечение витамином D [30].…”