A scoping review: the impact of nutritional status on the efficacy, effectiveness, and immunogenicity of COVID-19 vaccines.

BACKGROUND: Vaccination is one of the most effective strategies in mitigating the severity of SARS-CoV-2 infection. While a connection between poor nutritional status and diminished immune responses to vaccination has been noted, comprehensive reviews elucidating this association have been scarce. To address this gap, we conducted a scoping review to characterise the relationship between nutritional status (specifically, body mass index (BMI) or micronutrient deficiencies) and the responses to COVID-19 vaccination, encompassing efficacy, effectiveness, and immunogenicity. METHOD: We searched PubMed, OVID-Medline, Scopus, Cochrane Covid Register, LitCovid, and WHO COVID-19 research databases for studies that reported the association between nutritional status and responses to the COVID-19 vaccines (published between December 20, 2019, and December 30, 2023). Two reviewers independently screened the articles, and disagreements were resolved through consensus or by a third reviewer. RESULTS: Seventy-three out of 1,853 identified articles were included in this review, predominantly featuring cohort designs (72%). Among these studies, 63% reported BMI, 30% focused on micronutrients (specifically vitamin D, selenium, iron, zinc), and 6% examined both. Most studies (84%) focused on vaccine immunogenicity. The most frequently studied vaccines were BNT162b2 (Pfizer, 74%), ChAdOx (AstraZeneca, 23%), and mRNA-1273 (Moderna, 14%). High BMI significantly reduced COVID-19 vaccine immunogenicity in 23 studies, while adequate vitamin D was associated with increased vaccine response in seven studies. CONCLUSION: Overnutrition and micronutrient deficiencies (vitamin D, iron, selenium and zinc) have been observed to attenuate the potency of COVID-19 vaccines. Future strategies aimed at prioritizing vaccination in obese and overweight individuals, or enhancing their vaccine response, may involve identifying measures such as the provision of booster doses. Additionally, efforts should ensure micronutrient adequacy, including improving vitamin D status through strategies like increased sun exposure or supplementation, particularly for deficient individuals.