In addition, the T. pallidum DNA copy number (median, interquartile range) of saliva was higher in patients with primary syphilis (36,007 copies/mL, 20,162–570,823 copies/mL for tp47 and 220,956 copies/mL, 27,522–595,514 copies/mL for polA) and secondary syphilis (73,456 copies/mL, 29,959–311,672 for tp47 and 70,506 copies/mL, 12,266–266,266 copies/mL for polA) than in those with latent syphilis (11,391 copies/mL, 5,077–62,479 copies/mL for tp47 and 9,036 copies/mL, 5,320–56,422 copies/mL for polA) (Fig. 2B). Here, POLA1 is linked to latent syphilis.