Syphilis rates have increased markedly among men who have sex with men (MSM) in many
countries. This study examined trends in syphilis testing and detection of early syphilis
among MSM in Australia.
Serial cross-sectional analyses on syphilis testing and diagnoses among MSM attending a
national sentinel network of 46 sexual health clinics in Australia between 2007 and 2014.
There were 359,313 clinic visits included in the analysis, with 32% of clinic visits for HIVpositive
MSM. The proportion of MSM serologically tested for syphilis annually increased in
HIV-negative (48% to 91%, ptrend<0.0001) and HIV-positive MSM (42% to 77%,
ptrend<0.0001). The mean number of tests per man per year increased from 1.3 to 1.6 in HIVnegative
MSM (ptrend<0.0001) and from 1.6 to 2.3 in HIV-positive men (ptrend<0.0001). 2,799
and 1,032 early syphilis cases were detected in HIV-negative and HIV-positive MSM,
respectively. Among HIV-negative MSM the proportion of syphilis infections that were early
latent increased from 27% to 44% (ptrend<0.0001), while the proportion that were secondary
decreased from 24% to 19% (ptrend=0.030). Among HIV-positive MSM the proportion of
syphilis infections that were early latent increased from 23% to 45% (ptrend<0.0001), while
the proportion that were secondary decreased from 45% to 26% (ptrend=0.0003). Among HIVpositive
MSM there was a correlation between decreasing proportion of secondary syphilis
and increasing testing coverage (r=-0.87;p=0.005) or frequency (r=-0.93;p=0.001).
Major increases in screening for syphilis were associated with increased detection of
asymptomatic infectious syphilis and relative falls in secondary syphilis for both HIVpositive
and HIV-negative MSM nationally, suggesting interruption of syphilis progression
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