Trends in Deaths Due to Syphilis, United States, 1968-2015

Before penicillin, the syphilis case-fatality rate was 10% within 40 years. Late complications, such as cardiovascular syphilis, were still common in the 1950s but now seem quite rare even though some infections likely go undetected. We studied trends in syphilis mortality as an indicator of trends in severe complications of syphilis.

We assessed underlying cause of death from US death certificates for 1968 to 2015. We examined death trends by type of syphilis (cardiovascular, neuro, congenital, other). We compared trends in deaths with trends in primary and secondary syphilis from national STD surveillance data.

During 1968 to 2015, there were 6498 deaths attributed to syphilis, 4149 males and 2349 females. Annual syphilis deaths decreased from 586 in 1968 to 94 in 1984, then leveled off to between 24 and 46 since 1998. Between 1968 and 2015, the decrease in annual cardiovascular syphilis deaths (from 338 to 3) exceeded the decrease in annual neurosyphilis deaths (from 191 to 33). Congenital syphilis deaths (which do not include stillbirths) generally decreased from 28 to 2 per year. An increase in primary and secondary syphilis among women in the late 1980s was accompanied by a 4-fold increase in congenital syphilis deaths (from 9 in 1986 to 35 in 1990), but there was no subsequent increase in syphilis deaths among women.

Adults now rarely die from syphilis. Increases in infections in the late 1980s did not lead to an increase in adult syphilis deaths. Congenital syphilis deaths still increase when syphilis increases among women.