​Key Mess​ages  

​Table 1: Crosswalk comparing prior and updated CDPH syphilis scre​ening recommendations 

​Backgr​ound  

In 2020, the California Department of Public Health (CDPH) Sexually Transmitted Diseases (STD) Control Branch released Expanded Syphilis Screening Recommendations for the Prevention of Congenital Syphilis (CS) (PDF)[1​​​​]​​​​ to enable more timely identification of new syphilis infections in people who are or could become pregnant. Despite these efforts, syphilis rates in adults​​/adolescents and CS rose by 131 and 125 percent, respectively, from 2020 through 2022. CDPH S​TD Control Branch is thus releasing updated serologic screening guidelines to mitigate the ongoing syphilis and CS epidemics.  

The purpose of this letter is to inform clinicians in California of updated syphilis serologic screening recommendations for pregnant and non-pregnant persons. Recommendations now apply statewide, regardless of local syphilis ​or CS case rates, and include people of all genders and sexual orientations.

Recom​mendations  

1. All sexually active persons 15-44 years old, regardless of gender identity or sexual orientation, should now be screened for syphilis at least once in their lifetime. Following the initial screen, CDPH recommends that syphilis screening be offered annually to all sexually active people 15-44 years old. More​ frequent screening should be considered for sexually ​active adults and adolescents of any age at increased risk[i​​] of syphilis infection.  

2. Syphilis testing should be included whenever a person of any age is tested for HIV or other sexually transmitted infections, including mpox.

3. All pregnant persons, regardless of risk behaviors, should be scre​ened for syphilis three times:  ​

1. Once at confirmation of pregnancy or at the first prenatal encounter (ideally in the first trimester), 

2. Early in the third trimester (at approximately 28 weeks gestation or as soon as possible thereafter), and 

3. Again at delivery[ii​​​​​]. 

4. ​All persons 15-44 years old who enter a correctional facility should ideally be screened for syphilis​ at intake. If not completed at intake, syphilis screening should be done as close to intake as possible or included as part of the initial medical examination/health appraisal. 

5. Emergenc​y departments and hospital-affiliated urgent care clinics should screen all pregnant persons for syphilis prior to discharge if syphilis test results are not available for the current pregnancy.   ​

Rationale

Recommendations #1 and #2: CDPH first recommends all sexually active persons 15-44 years old – regardless of sex listed at birth, gender identity, or sexual orientation – receive at least one lifetime screen for syphilis and be offered screening annually thereafter. This change aligns with a recent U.S. Centers for Disease Control and Prevention (CDC) recommendation to offer syphilis screening to all sexually active persons aged 15-44 years old in counties with a primary and secondary syphilis rate among women 15-44 years old that is greater than 4.6/100,000 population (CDC ​MMWR[2​​​​][3​​​​​]) – a threshold derived from Healthy People 20​30 (HP 2030) objectives[4​​​​​​]. Although CDC does not delineate a screening frequency, given California’s high rates of syphilis and the fact that most individuals remain sexually active throughout their lifetime, CDPH believes offering annual screening will identify syphilis infections and control the epidemic.  

In California, the cumulative incidence of primary and secondary syphilis among women 15-44 years old (at 20.7/100,000 in 2022) far exceeds the HP 2030 threshold.  This HP 2030 threshold is also exceeded in 48 of the state’s 61 local health jurisdictions (with these 48 jurisdictions collectively encompassing 97.7% of California’s male and female populations 15-44 years old in 2022), further supporting statewide implementation of at least one-time syphilis screening among all sexually active people 15-44 years old.  

The expansion of syphilis screening to a minimum of one lifetime screen for sexually active people will also remove any requirement for patients to disclose or for clinicians to assess potentially stigmatizing sexual health risk factors and behaviors to determine eligibility for initial syphilis screening. Syphilis testing should also be included whenever a person of any age is tested for HIV or any other sexually transmitted infection (including mpox), given overlapping risk factors for these infections.  

Of note, the recommendation for a minimum of one lifetime screening for syphilis is inclusive of males aged 15-44, regardless of the genders of their sex partners. Current CDC guidelines recommend screening asymptomatic men who have sex with women (MSW) for syphilis only if certain risk factors are present, including age less than 29 years old. However, in California from 2021-2023 the incidence of total syphilis among MSW was higher among men 30-34 and 35-39 years old (99.6 and 90.4/100,000 respectively) than it was among people younger than 29 years old (25–29-year-olds: 83.2/100,000; 20–24-year-olds: 45.5/100,000; 15-19 year olds: 12.2/100,000). During this same time, MSW 25-39 years old also had an incidence of syphilis that surpassed the cumulative incidence among the total population of men who have sex with men of any age (MSM) (73.8/100,000) – a population that, regardless of age, is currently recommended to receive more frequent screening (at least annually) per current California and CDC screening guidelines. In 2022, the rate of total syphilis among women 15-44 years old was 110.6/100,000 people, higher than the rates of total syphilis among MSW or MSM. Hence, performing at least one lifetime syphilis screening for MSW 15-44 years old, and offering annual screening thereafter, are data-driven approaches to the prevention and control of syphilis. CDPH also anticipates that screening MSW for syphilis has the potential to reduce syphilis transmission to people who are or could become pregnant. 

This guidance regarding at least one lifetime syphilis screening for people aged 15-44 years old extends to non-binary populations, transgender women (TGW), transgender men (TGM), and other gender identities. While estimates of the rate of syphilis in these populations are difficult to determine because of limited population estimates, in 2022,  the most recent year for which data were available, the rates of total early syphilis in transgender men and women were 29.2 and 423.2 cases per 100,000 people, with the rate of total early syphilis among TGW being 5.26 times the rate of cisgender men and the rate in TGM 1.5 times that of cisgender women. CDC recommends for trans/gender diverse individuals to consider screening at least annually based on reported sexual behaviors and exposure.  

Following the initial screen, CDPH recommends that syphilis screening be offered annually to all sexually active people 15-44 years old. Offering annual screening is not a require​ment to test but allows for a recurring discussion around syphilis screening between health care providers and patients, thereby facilitating access to screening when desired. Patients who are at lower risk of syphilis exposures may be more likely to opt out of annual screening, thereby increasing the positive predictive value of the screening tests when performed. This approach is likely to: (1) diagnose syphilis infections that would not have otherwise been identified, and (2) allow providers to identify syphilis more effectively when 15–44-year-olds present for care, since people in this age range are less likely to access care than their older counterparts. 

Recommendation #3: For all pregnant persons, regardless of risk behaviors, CDPH now recommends screening for syphilis three times – once at confirmation of pregnancy or at the first prenatal encounter (ideally during the 1st trimester), early in the third trimester (at approximately 28 weeks gestation or as soon as possible thereafter), and again at delivery. This change to universal three-time screening in pregnancy is consistent with new recommendations recently put forth in April 2024 by the America​​n College of Obstetricians and Gynecologists (ACOG)[5​​] and is a practice already implemented in multiple other states (including but not limited to Alabama, Arizona, Georgia, New Jersey, North Carolina, and Texas), some of which had lower rates of CS in 2022 than California.   

In 2022, over 98% of pregnancies in California were in local health jurisdictions that would have been screened for syphilis at delivery based on the previous 2020 syphilis screening guidelines. The purpose of changing to universal at-delivery screening is to simplify implementation since providers may not always know the syphilis rates in the counties where their patients (or their partners) live, thus making testing routine rather than risk-based. The goals of these updated pregnancy screening include: (1) detecting CS cases that may otherwise be missed, (2) providing prompt treatment, and (3) averting potential CS sequelae. Similar to CDC reco​​mmendations[6​​​​], CDPH continues to recommend that third trimester syphilis screening be done early in the third trimester – at approximately 28 weeks gestation or as soon as possible thereafter. Since syphilis treatment among pregnant persons must begin at least 30 days prior to delivery to prevent CS, screening as early as possible in the third trimester increases the likelihood of timely diagnosis and treatment to effectively prevent CS.

[i​]Individuals at increased risk for syphilis include men who have sex with men, persons with HIV or on HIV pre-exposure prophylaxis, pregnant people with late or limited prenatal care, and people experiencing homelessness or unstable housing, methamphetamine use, incarceration (within past year), or with a new/recent STI diagnosis. 

[ii​​] California Health and Safety Code 120685(a) requires “every licensed health care professional engaged in providing prenatal care or attending a birthing patient at the time of delivery” to provide syphilis screening as outlined in the most recent CDPH guidelines.​​