Syphilis, the sexually transmitted infection (STI) that was once near elimination in the US, is now increasing at an exponential rate in the country once again.
According to the US Centers for Disease Control and Prevention (CDC) STI surveillance report, the prevalent cases of the disease increased by 80% from 2018 to 2022, with particular concern regarding congenital syphilis, which increased at an even higher rate of 183.4% over the five years.
The wide availability of diagnostics and treatments for syphilis in the US makes this resurgence even more concerning, as hypothetically no cases of syphilis should be left undetected.
However, with the shift in funding over the past decade, the focus on sexual health screenings has been deprioritised across the US.
With this in mind, leading data and analytics company GlobalData epidemiologists anticipate that the diagnosed incident cases of syphilis will continue to increase year-on-year if there is not an increased effort to ensure vulnerable groups are being routinely tested.
Syphilis is transmitted from person-to-person via direct contact with a syphilitic sore, known as a chancre.
Within 21 days of initial infection, the patient typically presents with a painless chancre in, on, and around the penis, vagina, anus, rectum, lips, or mouth, which can be unnoticeable in many cases.
If identified and treated, the syphilis infection will disappear within three to six weeks; however, if untreated it will develop into stage two syphilis, which involves a rash and fever, and can be easily mistaken for many other diseases.
Again, if left untreated during the second stage, the patient will progress into the latent stage of the disease, where there are no visible signs or symptoms - the patient can remain in this stage for several years.
After 10-30 years, tertiary syphilis develops, which can affect all organ systems and result in death.
Pregnant people should receive syphilis testing at their first prenatal appointment, as if infected, the mother can transmit the disease to their unborn child.
Particularly vulnerable mothers such as those living in an area with high syphilis incidence, those having sex with multiple partners, drug users, and those who are incarcerated or homeless, should also be tested again in the third trimester.
If an infected pregnant woman is not diagnosed, and subsequent penicillin therapy is not administered to prevent transmission to the baby, it is likely that the child infected with congenital syphilis will be stillborn, or will develop serious health problems within their early weeks.
In 1999, the US was on track to eradicate syphilis, experiencing the lowest case numbers it had in many years.
This was likely attributed to the fear associated with human immunodeficiency virus (HIV), which was untreatable at the time.
But with the introduction of preexposure prophylaxis (PrEP), which prevents HIV infection, sexual behaviours have changed over time, and there is less of a public health focus on syphilis prevention, which has been underfunded and deprioritised since.
This is reflected in the increase in the number of syphilis infections reported by the CDC, which reported 113,739 cases of syphilis in 2018, which increased to 203,500 cases in 2022; 3,755 of the cases reported in 2022 were congenital syphilis, meaning that these mothers had not been tested during pregnancy.
Khalil Ganem, a professor of medicine at Johns Hopkins Bloomberg School of Public Health, says that every congenital case of syphilis is a "black mark on public health," as all cases should have been detected and treated before they could develop.
This highlights the importance of re-establishing regular screening regimes and ensuring that all pregnant women have access to healthcare throughout their pregnancy.
It is also important that a disease-specific approach is applied, as the asymptomatic nature of the disease, and the stigma associated, create issues that are not as problematic when approaching other STIs such as gonorrhoea and chlamydia.
According to GlobalData epidemiologists, in 2029 there will be 43,700 diagnosed incident cases of HIV in the US, and there will be 451,700 people using PrEP, who are especially vulnerable to syphilis.
GlobalData epidemiologists anticipate that if routine screening is made a priority among vulnerable groups such as pregnant people, men who have sex with men, people with HIV, and those using PrEP, cases will begin to decline and the US can regain control over the syphilis epidemic.
