Extended Data Fig. 2: Effects of age, sex and continent of birth are not confounded by batch effects.

a, Principal component analysis of the Milieu Intérieur dataset, before batch correction (n = 2,608 public peptide Z-scores). Colors indicate sequencing batches. b, Principal component analysis of the Milieu Intérieur dataset, after batch correction. Colors indicate age decades in years. c, Variance explained by batches before batch correction against that explained by age after batch correction, in the Milieu Intérieur cohort. d, Principal component analysis of the Milieu Intérieur dataset, after batch correction. Colors indicate sex. e, Variance explained by batches before batch correction against that explained by sex after batch correction, in the Milieu Intérieur cohort. f, Principal component analysis of the EIP dataset, before batch correction (n = 3,210 public peptide Z-scores). Colors indicate sequencing batches. g, Principal component analysis of the EIP dataset, after batch correction. Colors indicate continent of birth (AFB: Belgians born in Central Africa; EUB: Belgians born in Europe). h, Variance explained by batches before batch correction against that explained by continent of birth after batch correction, in the EIP cohort. i, Variance explained by batches before batch correction in EUB samples only against that explained by continent of birth after batch correction, in the EIP cohort. h,i, The black line indicates the identity line. c,e,h,i, Colors indicate viral families.