The effects of COVID-19 and B12 on the methylation levels of the 21 CpGs located in the promoter region and proximal portion of the first exon of the CCL3 gene (GRCh38/hg38 chr17: 36,090,276 - 36,090,005) were evaluated by Bisulfite Sequencing PCR in an NGS platform from DNA libraries produced with aliquots of endpoints A and B from individuals representing MOD, SEV and CTRL groups. Here, CCL3 is linked to COVID-19.