Effectiveness of COVID-19 vaccines might be increased by Vitamin D – Aug 2021

Putative Role of Vitamin D for COVID-19 Vaccination

Int. J. Mol. Sci. 2021, 22(16), 8988; https://doi.org/10.3390/ijms22168988
by Sheng-Kang Chiu 1,2,3,†,Kuo-Wang Tsai 4OrcID,Chia-Chao Wu 5,6OrcID,Cai-Mei Zheng 7OrcID,Chung-Hsiang Yang 8,†,Wan-Chung Hu 4,*OrcID,Yi-Chou Hou 9,Kuo-Cheng Lu 10OrcID andYou-Chen Chao 11

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Severe acute respiratory syndrome coronavirus 2 is a new, highly pathogenic virus that has recently elicited a global pandemic called the 2019 coronavirus disease (COVID-19). COVID-19 is characterized by significant immune dysfunction, which is caused by strong but unregulated innate immunity with depressed adaptive immunity. Reduced and delayed responses to interferons (IFN-I/IFN-III) can increase the synthesis of proinflammatory cytokines and extensive immune cell infiltration into the airways, leading to pulmonary disease. The development of effective treatments for severe COVID-19 patients relies on our knowledge of the pathophysiological components of this imbalanced innate immune response. Strategies to address innate response factors will be essential. Significant efforts are currently underway to develop vaccines against SARS-CoV-2. COVID-19 vaccines, such as inactivated DNA, mRNA, and protein subunit vaccines, have already been applied in clinical use. Various vaccines display different levels of effectiveness, and it is important to continue to optimize and update their composition in order to increase their effectiveness. However, due to the continuous emergence of variant viruses, improving the immunity of the general public may also increase the effectiveness of the vaccines.
Many observational studies have demonstrated that serum levels of vitamin D are inversely correlated with the incidence or severity of COVID-19. Extensive evidence has shown that vitamin D supplementation could be vital in mitigating the progression of COVID-19 to reduce its severity. Vitamin D defends against SARS-CoV-2 through a complex mechanism through interactions between the modulation of innate and adaptive immune reactions, ACE2 expression, and inhibition of the renin-angiotensin system (RAS). However, it remains unclear whether Vit-D also plays an important role in the effectiveness of different COVID-19 vaccines. Based on analysis of the molecular mechanism involved, we speculated that vit-D, via various immune signaling pathways, plays a complementary role in the development of vaccine efficacy.

Vaccine trials were not as effective in regions with low vitamin D (clipped from introduction)

A recent article regarding the effectiveness of two inactivated SARS-CoV-2 vaccines on cases of COVID-19 reported that the vaccine efficacy was around 72-78% in the United Arab Emirates and Bahrain [7]. In contrast, BNT162b2 and mRNA-1273 (both coding for the spike S1 protein) are two newly approved COVID-19 mRNA vaccines that have demonstrated excellent safety and effectiveness. BNT162b2 and mRNA-1273 have shown satisfactory safety and efficacy profiles, with an effectiveness of around 94-95%, based on data from the U.S. or mainly from the U.S. [8], where vitamin D food fortification has been mandatory for several year.Thus, we speculated that the relatively low vaccine efficacy of inactivated SARS-CoV-2 vaccines is due, at least in part, to low vitamin D levels in the study population (in the Middle East region). Whether vitamin D supplementation in the vitamin D deficiency population will mitigate this disadvantage merits further investigation.