Influence of vitamin D supplementation on SARS-CoV-2 vaccine efficacy and immunogenicity

Background & Aims Vitamin D deficiency has been reported to associate with impaired development of antigen-specific responses following vaccination. We aimed to determine whether vitamin D supplements might boost immunogenicity and efficacy of SARS-CoV-2 vaccination. Methods We conducted three sub-studies nested within the CORONAVIT randomised controlled trial, which investigated effects of offering vitamin D supplements at a dose of 800 IU/day or 3200 IU/day vs. no offer on risk of acute respiratory infections, including COVID-19, in UK adults with circulating 25-hydroxyvitamin D concentrations <75 nmol/L. Sub-study 1 (n=2808) investigated effects of vitamin D supplementation on risk of breakthrough SARS-CoV-2 infection following two doses of SARS-CoV-2 vaccine. Sub-study 2 (n=1853) investigated effects of vitamin D supplementation on titres of combined IgG, IgA and IgM (IgGAM) anti-Spike antibodies in eluates of dried blood spots collected after SARS-CoV-2 vaccination. Sub-study 3 (n=100) investigated effects of vitamin D supplementation on neutralising antibody and cellular responses in venous blood samples collected after SARS-CoV-2 vaccination. Results 1945/2808 (69.3%) sub-study 1 participants received two doses of ChAdOx1 nCoV-19 (Oxford–AstraZeneca); the remainder received two doses of BNT162b2 (Pfizer). Vitamin D supplementation did not influence risk of breakthrough SARS-CoV-2 infection (800 IU/day vs. no offer: adjusted hazard ratio 1.28, 95% CI 0.89 to 1.84; 3200 IU/day vs. no offer: 1.17, 0.81 to 1.70). Neither did it influence IgGAM anti-Spike titres, neutralising antibody titres or IFN-γ concentrations in supernatants of S peptide-stimulated whole blood. Conclusions Among adults with sub-optimal baseline vitamin D status, vitamin D replacement at a dose of 800 or 3200 IU/day did not influence protective efficacy or immunogenicity of SARS-CoV-2 vaccination. Clinical Trial Registration [ClinicalTrials.gov][1] [NCT04579640][2]. ### Competing Interest Statement ARM declares receipt of funding in the last 36 months to support vitamin D research from the following companies who manufacture or sell vitamin D supplements: Pharma Nord Ltd, DSM Nutritional Products Ltd, Thornton & Ross Ltd and Hyphens Pharma Ltd. ARM also declares receipt of vitamin D capsules for clinical trial use from Pharma Nord Ltd, Synergy Biologics Ltd and Cytoplan Ltd; support for attending meetings from companies who manufacture or sell vitamin D supplements (Pharma Nord Ltd and Abiogen Pharma Ltd); receipt of a consultancy fee from DSM Nutritional Products Ltd; receipt of a speaker fee from the Linus Pauling Institute; participation on Data and Safety Monitoring Boards for the VITALITY trial (Vitamin D for Adolescents with HIV to reduce musculoskeletal morbidity and immunopathology, Pan African Clinical Trials Registry ref PACTR20200989766029) and the Trial of Vitamin D and Zinc Supplementation for Improving Treatment Outcomes Among COVID-19 Patients in India (ClinicalTrials.gov ref [NCT04641195][3]); and unpaid work as a Programme Committee member for the Vitamin D Workshop. All other authors declare no competing interests. ### Clinical Trial NCT04579640 ### Funding Statement This study was funded by the Exilarch’s Foundation, DSM Nutritional Products Ltd, the Fischer Family Foundation, Pharma Nord Ltd and a personal donation from Prof Barbara Boucher. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the Queens Square Research Ethics Committee, London, UK (ref 20/HRA/5095). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes Anonymised participant-level data will be made available on reasonable request to a.martineau@qmul.ac.uk, subject to the terms of Research Ethics Committee and Sponsor approval. [1]: http://ClinicalTrials.gov [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04579640&atom=%2Fmedrxiv%2Fearly%2F2022%2F07%2F18%2F2022.07.15.22277678.atom [3]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04641195&atom=%2Fmedrxiv%2Fearly%2F2022%2F07%2F18%2F2022.07.15.22277678.atom