Reply to Kenyon

To the Editor—We thank Chris Kenyon for his comments [1] on our recent article [2], which showed that increased syphilis testing is associated with a relative increase in detection of asymptomatic early latent syphilis and a fall in secondary syphilis. Kenyon has hypothesized that the increase in proportion of early latent syphilis may be explained by an increasing proportion of repeated syphilis infections, which in turn are more likely to be asymptomatic [1]. However, we believe this is unlikely to explain our observations. In response, we undertook a further analysis of repeated syphilis infections among men who have sex with men (MSM) attending the Melbourne Sexual Health Centre (MSHC), where 32% of syphilis cases (1215 of 3831) in our study were diagnosed. Repeated syphilis infections were identified based on patient self-reported past history of syphilis using computer-assisted self-interview (CASI) at the MSHC from mid-2008 to ensure complete capture of diagnoses if patients had tested elsewhere outside the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance of Sexually Transmissible Infections and Blood-borne Viruses (ACCESS) network.