In a recent study of genetic data from large contemporary human biobanks, it was shown that SNV’s that tag haplotype A of ERAP2 was associated with protection against respiratory infections, with increased ERAP2 expression in whole blood (i.e., haplotype A) being associated with protection against severe respiratory infection (such as Pneumonia and Covid-19), but with opposing effects on Crohn’s disease [4]. This evidence concerns the gene ERAP2 and Crohn disease.