# Effect of vitamin D3 on antiphospholipid antibodies in hospitalized patients with moderate to severe COVID-19

## TL;DR

A high dose of vitamin D3 did not reduce antiphospholipid antibodies in hospitalized patients with moderate to severe COVID-19.

## Contribution

This study provides evidence that a single high dose of vitamin D3 does not modulate autoantibodies in hospitalized COVID-19 patients.

## Key findings

- A single dose of 200,000 IU of vitamin D3 did not modulate autoantibodies in hospitalized patients with moderate to severe COVID-19.
- aPL antibody positivity was not associated with thrombotic events despite vitamin D3 supplementation.
- aPL antibodies associated with the virus appear to be transient in critical patients.

## Abstract

•The impact of vitamin D3 supplementation on autoimmunity remains a subject of debate.•A single dose of 200,000 IU of vitamin D3 was not able to modulate autoantibodies in COVID-19 patients.•aPL antibody positivity was not associated with thrombotic events despite vitamin D3 supplementation.•aPL antibodies associated with the virus seem to be transient in critical patients.

The impact of vitamin D3 supplementation on autoimmunity remains a subject of debate.

A single dose of 200,000 IU of vitamin D3 was not able to modulate autoantibodies in COVID-19 patients.

aPL antibody positivity was not associated with thrombotic events despite vitamin D3 supplementation.

aPL antibodies associated with the virus seem to be transient in critical patients.

To investigate the effect of a single oral dose of 200,000 IU of vitamin D3 on antiphospholipid antibodies in hospitalized patients with moderate to severe COVID-19.

This is a post-hoc, exploratory analysis from a double-blind, placebo-controlled, randomized clinical trial performed in two centers in Sao Paulo, Brazil. Hospitalized patients with COVID-19 were randomly assigned to receive either vitamin D3 (n = 97) or placebo (n = 97). In this post-hoc analysis, the endpoints were titers and frequency of anti–β2-Glycoprotein-I (aβ2-GP) and Anticardiolipin (aCL) antibodies [Immunoglobulin G, M and A (IgG, IgM and IgA)].

Overall mean (SD) age was 55.3 (13.9) years, Body Mass Index (BMI) was 32.2 (7.1 kg/m2), and 106 participants (54.6 %) were male. There was a significant group by time interaction (p = 0.046) for frequency of aCL IgG, with increased values from baseline to discharge in the placebo group [n (%), from 13 (13.4) to 25 (25.8)] compared to the vitamin D3 [from 25 (25.8) to 29 (29.9)]. However, the frequency of aCL IgG did not change between the groups on discharge. No significant differences between vitamin D3 and placebo groups were found for any other autoantibodies.

These findings do not support the use of a single oral dose of 200,000 IU of vitamin D3 to modulate autoantibodies in hospitalized patients with moderate to severe COVID-19.