Case rates of syphilis have increased over the past decade across the United States. According to data
from the San Bernardino County case rates across the US have roughly doubled over the five-year period
between 2013 and 2018. Over that same period, in San Bernardino County, the case rates have
increased from 3.6 cases per 100,000 residents to 14.6 cases per 100,000. The case rate of San
Bernardino County is not as high as the California average; however, the steep rise of the curve requires
attention. Even more concerning to some is the steep increase in cases of congenital syphilis. According
to the SBC data that rates of congenital syphilis increased from 13.1 per 100,000 in 2015 to 99.9 in 2017
and in 2018. 1
Syphilis refers to an infection caused by a spirochaete bacterium called Treponema pallidum, of which
there are 3 subspecies.2 The bacterium is primarily spread through oral, anal, and vaginal intercourse.
However, it can also be transmitted through contaminated blood and congenitally from the mother to
her unborn child. The bacterium cannot survive outside of the host so inoculation from contact with
objects within the environment, which is a concern for some other types of infections.3 Syphilis is spread
during sexual contact from the syphilitic core or chancre, which is typically a painless ulcer in the skin.
This chancre can be visible on the exterior of the genitalia/mouth or internal and therefore not visible.4
Syphilis can also be spread during the latent stage, where there are no symptoms.
The range of health hazards stemming from a syphilis infection are broad because it can affect many
organ systems, including, but not limit to, the eyes, ears, skin, central nervous system, and the
cardiovascular system. The primary syphilis stage is indicated by a painless ulcer in the skin at the site
where the spirochaete burrowed into the skin. Secondary syphilis occurs later in the infection and
typically causes a diffuse body rash. Syphilis can progress to Tertiary syphilis and Neurosyphilis which
can cause permanent neurological deficits or death. Syphilis can affect the ocular system leading to
permanent blindness and it can even cause aortic aneurysms. Congenital syphilis infections can be fatal
in utero. If the child survives, congenital syphilis causes a wide range of permanent defects.4
Anyone who is sexually active is at risk of contracting syphilis. This risk increases in those who have
multiple sexual partners, have unprotected intercourse, perform sexual acts for money, engage in same
sex practices, incarcerated individuals and those who inject IV drugs. Anyone who is at risk for
contracting syphilis is a stakeholder. Healthcare providers including primary care physicians, nurses,
pediatricians, infectious disease specialists, obstetricians, gynecologists, neurologists, cardiologists, and
geriatricians are all stakeholders. Organizations that support reproductive health such as our public
health systems and Planned Parenthood are also invested in this problem. Lastly, organizations that help
vulnerable populations like homeless shelters, substance use programs and treatment centers should
also have a vested interest.
If oral or sexual intercourse is performed the only reliable way of reducing the spread of infection is with
external or internal condoms. These condoms would be considered, personal protective equipment
(PPE) and would be individual controls. Contraceptive pills, rings, IUDs, or implantable devices do not
protect against the spread of syphilis. Similarly, internal diaphragms or withdrawing prior to ejaculation
do not protect against syphilis. Correct and consistent condom can reduce the risk of transmission;
however, it does not eliminate the risk. Syphilis chancroids can be present in an area of skin that is not
covered by the condom. Condoms can also fail (slip or break) even with correct and consistent use.
Condoms can also have manufacturing defects decreasing effectiveness.5 This form of PPE is overall very
inexpensive, especially when compared to testing and treatment, however it is less effective. The
effectiveness is greatly limited because it is depending on correct and consistent use. Condoms
represent the point of the Hierarchy of Controls.
Preventing the rising incidence rates of syphilis infections require administrative and engineering
policies to identify and eradicate infections in the population. This is challenging because many cases are
asymptomatic. Unlike other infections, syphilis can be transmitted at any point within the disease
process, even by asymptomatic individuals. This aspect highlights the need for increased education
about the risks of syphilis and how to minimize those risks. Increased education about this infection
would be an Administrative Control. This education could be conducted in many ways including
pamphlets/posters in clinic waiting rooms, education in middle/high school health class, college
education, and directly from their physician. Although this education would be beneficial, it would be
costly to implement. The effectiveness of this control is also highly dependent on how receptive the
audience is, which is a limitation.
To reduce incidence of congenital syphilis the CDC, the U.S. Preventive Services Task Force (USPSTF) and
the American College of Obstetrics and Gynecology (ACOG) all agree screening of asymptomatic persons
is recommended at the initial prenatal visits and during the third trimester for those at higher risk.
Testing should be performed in anyone experiencing symptoms or any mother who is exposed. Syphilis
can be treated if infections are discovered, which reduce the risks of congenital syphilis. Treatment can
become challenging during pregnancy if the mother is allergic to penicillin because there are no proven
alternative treatments to penicillin during pregnancy.6,7,8 Treating someone who has a severe allergy to
penicillin would require a hospital supervised desensitization protocol which is costly to the healthcare
system. There are no formal recommendations for screening females who desire to become pregnant.
An administrative change would be to expand screening tests to any female who is trying to conceive.
This would reduce the number of prenatal cases of syphilis. This policy change would increase the
number of tests performed, but this increase would not carry a significant financial burden when
compared to the increased costs of prenatal treatment or treatment of congenital syphilis cases. The
effectiveness of this change in screening hinges on preconception planning, which according to the CDC,
in 2011 approximately 45% of pregnancies were unplanned. 10
A similar administrative control would be to increase asymptomatic screening. Currently the CDC
recommends only screening individuals at higher risk, which include persons with HIV, incarcerated
persons, persons engaging in sex acts for money, transgender persons, and persons engage in same sex
practices. The screening frequency is broad, ranging between yearly to every 3 months. Comparatively,
the CDC and USPSTF recommend screening all sexually active females under age 25 on a yearly basis.7 It
is my recommendation that screening should be expanded to include sexually active females and males,
regardless of the type of sexual acts they engage in. This change would significantly increase the number
of tests performed. In high incidence areas such as San Bernardino, this would also increase the number
of cases identified. If cases are identified and eradicated, reducing spread of disease, and reducing
complications from infection.
Expanding the number of screening tests performed requires the infrastructure to handle that volume of
tests which is a barrier to this policy benefiting the public health system. Currently syphilis and other
STD tests can be performed for free or at low cost from a variety of organizations that include Planned
Parenthood, SBC Public Health, and at any primary care clinic. Some labs such as Labcorp or Quest can
perform these tests without a physician order. Cost of testing is varied, however both Planned
Parenthood and the SBC PH clinics will offer free or discounted tests.
According to San Bernardino County Public Health, it is mandatory for a healthcare provider to report a
syphilis infection within 1 working day of identification. Instructions of how to report are available
online. There are many reasons why this reporting system is beneficial. The Communicable Disease
Section (CDS) works to minimize the spread of the disease by contacting the infected persons. The CDS
can provide information and support to that person so they can receive timely treatment.11 An
engineering control would be to have an automated reporting system. If reportable conditions are
identified the health record could automatically contact the CDS. This would reduce the number of cases
left unreported. This engineering change would be costly and would be technically challenging because
of the various electronic health record systems.
Elimination of syphilis within a population is possible because it is only transmitted between humans
through intimate contact, vertically to fetus, and through infected blood. Vectors such as mosquitoes
cannot spread human-based STDs. Elimination of the syphilis pathogen would require identification and
treatment of all infected persons within a population. The smaller and more isolated the population the
easier it would be to eliminate syphilis. This becomes progressively more challenging with increasing
population size, increasing contacts between members of that population, and travel between discrete
populations. Eradication is challenging because the infection can be asymptomatic for years and in some
cases infected persons are unaware of the infection their entire life. The infection also causes such a
wide range of symptoms that these symptoms may be mistaken for another illness. Syphilis can be
difficult to diagnose and adequately treat because of limitations with certain testing methods. Because
of these reasons, eliminating syphilis in a large population such as San Bernardino County is not a
feasible goal. However, elimination of syphilis in persons who are identified to reduce incidence of new
infections is possible and is a worthwhile goal.
Elimination through adequate treatment requires identification and correct categorization of cases.
Treatment methods differ depending on the category of the syphilis infection. Intramuscular or
intravenous penicillin is the preferred treatment of adult cases at any stage of infection. Patients
experiencing classical symptoms of primary or secondary syphilis, or those with a known exposure of
less than 12 months can be treated with 1 dose of 2.4 million units of penicillin. Persons without obvious
symptoms of primary/secondary syphilis and who have an unclear exposure history should be managed
as late-latent syphilis (>12 months) requiring a 3-dose series of 2.4 million units each. Treatment of
neuro, ocular, or otosyphilis requires 10-14 days of IV penicillin.12
Identification and classification can be challenging, latent syphilis can be present for years without any
obvious symptoms and therefore late latent syphilis cases can mistakenly be treated as early latent.
Inadequate treatment of false early latent syphilis can result in a failure to clear the infection. If this
treatment failure is not identified, this person can continue to spread the infection. One change to the
elimination procedure would be to treat early latent cases the same as late latent cases, with 3 doses of
penicillin spaced 7 days apart. This change would reduce incidence of misclassification and suboptimal
treatment. This would be an effective strategy for clearing a patient’s infection, however this increases
burden on the patient and clinic because they would need to have 3 visits instead of 1. Increasing the
number of visits would increase treatment nonadherence and would increase a clinic’s cost to treat a
case of syphilis. The cost of penicillin is low compared to the cost of 2 extra clinic visits. The costs can be
reduced by having nurse only visits for the 2nd and 3rd doses.
Misinterpretation of lab tests is also a source of false negatives. The classical testing algorithm involves a
non-treponemal test such as the RPR, if the RPR is negative then no further testing is typically
performed, and the patient is deemed “negative.” The RPR screening method is flawed because the RPR
levels will fall over time during a late latent infection and can be falsely “normal.” One strategy that is
being implemented in high incidence areas such as San Bernardino is a reverse algorithm which uses a
treponemal antibody test as the initial screening test. The treponemal antibodies will be positive for life
and if positive they indicate an active infection or a previously treated infection. Another change to the
current elimination strategy would be to expand the use of the reverse screening algorithm. This change
would result in more false positives, but would reduce the number of false negatives. Increasing the
number of false positives would possibly result in overtreatment of some patients. The risk of
overtreatment is low compared to the individual and public health risks of missed cases.
The final most effective elimination control is abstinence, however this strategy has it’s obvious
limitations on a population scale. Another similar strategy is monogamous relationships where both
partners have tested negative and/or have been fully treated. The success of this strategy is dependent
on fidelity, which highlights the main obstacle for success. For the best success in prevention of syphilis
each partner should be tested prior to engaging in intimate activities with a new partner or if an
additional partner enters the relationship. Elimination controls are often the most effect, but also the
most expensive. Abstinence and relational fidelity are, interestingly, very cost effective. These two
controls are inexpensive monetarily, but some may consider them costly because of the behavioral
changes necessary.
There are no viable options for a substitution control, this would not be beneficial to the public.
Substitution involves replacing the hazard with a safer alternative. There is no safer alternative to a
syphilis infection.
Many of these strategies would be perceived well by the stakeholders identified, however the
challenges in implementation and the costs are barriers. Increased and improved education on the risks
of syphilis and how to reduce infections would be well received by our educational systems. Similarly
improved physician education on how to correctly identify and treat the different stages of syphilis
would also be well received because of the complexity of this topic. Expanding the screening for syphilis
would also be well received, but likely slow to implement to evaluate if this expanded screening will
have unseen harms prior to widespread policy change. Encouraging abstinence, which if performed, is
the most effective control, however it is also the least practical of the controls.
The rising incidence rates of syphilis infections including congenital syphilis in San Bernardino County is a
critical health topic. Public health policy changes will need to be implemented if there is going to be any
change to the rapidly increasing incidence rates. The complexity of the infection is the primary driver to
these incidence rates, which will require improved education. Infected persons can be asymptomatic for
decades while they spread the pathogen, or they can present with disease mimics that are misclassified
which necessitates expanded screening. Syphilis is also challenging to correctly stage and treat, which
are necessary for elimination from the host.
References AMA 11th Edition:
1. Sexually transmitted diseases. San Bernardino County Community Indicators. Accessed October 6,
2022. https://indicators.sbcounty.gov/wellness/sexually-transmitted-desease/
2. Low N, Stroud K, Lewis DA, Cassell JA. Mind your binomials: a guide to microbial nomenclature and
spelling in Sexually Transmitted Infections. Sex Transm Infect. 2015;91(3):154-155.
doi:10.1136/sextrans-2014-051937
3. Syphilis - sti treatment guidelines. Published July 21, 2022. Accessed October 6, 2022.
https://www.cdc.gov/std/treatment-guidelines/syphilis.htm
4. Detailed std facts - syphilis. Published October 6, 2022. Accessed October 12, 2022.
https://www.cdc.gov/std/syphilis/stdfact-syphilis-detailed.htm
6. Condom fact sheet in brief | cdc. Published September 14, 2021. Accessed October 12, 2022.
https://www.cdc.gov/condomeffectiveness/brief.html
7. US Preventive Services Task Force, Mangione CM, Barry MJ, et al. Screening for syphilis infection in
nonpregnant adolescents and adults: us preventive services task force reaffirmation recommendation
statement. JAMA. 2022;328(12):1243. doi:10.1001/jama.2022.15322
8. Sti screening recommendations. Published June 6, 2022. Accessed October 19, 2022.
https://www.cdc.gov/std/treatment-guidelines/screening-recommendations.htm
9. Chlamydia, gonorrhea, and syphilis. Accessed October 19, 2022. https://www.acog.org/en/womenshealth/faqs/chlamydia-gonorrhea-and-syphilis
10. Unintended pregnancy | unintended pregnancy | reproductive health | cdc. Published July 20, 2021.
Accessed October 19, 2022.
https://www.cdc.gov/reproductivehealth/contraception/unintendedpregnancy/index.htm
11. About cds | department of public health. Accessed October 19, 2022.
https://wp.sbcounty.gov/dph/programs/cds/about-cds/
12. P&s syphilis - sti treatment guidelines. Published July 21, 2022. Accessed October 25, 2022.
https://www.cdc.gov/std/treatment-guidelines/p-and-s-syphilis.htm