HLA-C and susceptibility to pneumonia measurement: Due to the complexity of this region, we define the MHC signal as a single locus, with the minor allele of the lead common SNP associated with a small increase in the odds of pneumonia (rs9275211-C allele: OR = 1.06 [95% CI: 1.05, 1.08], P = 3.83 × 10−14).