In summary, based on the literature and our findings, we speculate that one or more of the multiple PVR and PVRL2 genetic variants, associated with variation in rubella vaccine-specific neutralizing antibody levels, or other tagged causal SNP/SNPs in the 19q13 region, influence the gene expression and/or protein function of CD155 (PVR) and CD112 (PVRL2). The gene discussed is PVR; the disease is rubella.