Sex, drugs and transmitted infections

Individuals with substance use and substance use disorders (SUDs) are at increased risk for sexually transmitted infection (STI) comorbidities. Most STIs are asymptomatic, especially during early stages. Therefore, engaging these individuals in treatment is challenging and a public health concern. Individuals with SUD also represent special populations requiring testing for STIs such as HIV, hepatitis, and syphilis due to increased risk from unsafe sexual behaviors, drug injection-related behaviors, and socioeconomic and health disparities.^1,2 Urine drug testing and risk assessment tools support SUD and STI diagnoses permitting implementation of appropriate treatment plans, including overdose prevention, harm reduction strategies, antiviral prophylaxis and antimicrobial therapies.

What is a syndemic? The interaction of SUDs, STIs, and health inequities

The co-occurrence of SUDs and STIs is considered a syndemic. Syndemics occur when two or more diseases or health conditions interact within a population because of social and structural factors, increasing adverse effects on health and exacerbating health inequities. Social determinants of health, such as racism, homophobia, and poverty, interact with syndemic conditions. Integrating infectious disease services at substance treatment programs is necessary to enhance prevention, screening, and treatment by addressing gaps in patient care and supporting recovery.³

Reducing the stigma of addiction is essential. SUD is a treatable, chronic disease that can affect anyone. SUDs range in severity from mild to severe and may be recognized through self-awareness or by friends and family. Unfortunately, many individuals with SUD do not acknowledge their disease before negative consequences occur, such as job loss, homelessness, accidents, incarceration, disease, or death.

Drug use and mental illness often co-exist. Mental disorders such as anxiety, depression, or schizophrenia may present before addiction or evolve from addiction.⁴ Those with mental disorders may use drugs to alleviate psychiatric symptoms, while those with SUD may use drugs to improve mood, enhance pleasure, reduce stress, or engage socially. These behaviors increase risk of exposure to infectious diseases. Those with SUD and STIs may transmit disease through sexual contact, sharing needles, or unsafe living conditions.

Expanding access to SUD care is essential

Nearly 1 in 5 people ages 12 and older (17.1%) had an SUD, according to the 2023 National Survey on Drug Use and Health (NSDUH). Yet only 23.6% received any substance use treatment.⁵ Common drugs for those with SUD are opioids, marijuana, and alcohol. Polypharmacy—using two or more drugs together—is common. Health access disparities, SUD stigma, inconsistencies in care, perceived lack of need, and cost contribute to low treatment utilization.

Identifying individuals with SUD or self-recognition of SUD in need of assistance is key.⁶ The American Society of Addiction Medicine (ASAM) developed guidance on the effective use of drug testing in identification, diagnosis, treatment, and promotion of recovery for patients with, or at risk for, addiction.⁷ Clinical studies demonstrate urine drug tests are important assessment tools when treating and monitoring SUDs.^8-14 The U.S. Department of Health and Human Services’ Substance Abuse and Mental Health Services Administration (SAMHSA) and other agencies also support SUD/STI programs and integrated care models in states, cities, and community-based organizations.

The path to finding access to and the financial burden of SUD care can be overwhelming. The CDC Overdose Prevention web page provides guidance to treatment and recovery options. Evidence-based guidelines and training assist providers with evaluating clinical needs and level of care. For example, opioid use disorder (OUD) has FDA-approved medications including methadone, naltrexone, and buprenorphine. Each requires different levels of monitoring. Methadone should be dispensed by a SAMHSA-certified opioid treatment program and is effective for OUD but has potential for cardiac arrhythmias and increased mortality, so treatment must be monitored. Buprenorphine and naltrexone have decreased risk of cardiac and mortality outcomes and are effective for OUD and preventing overdose. These drugs are dispensed at different intervals based on dosing and half-lives and should be monitored for compliance.

SUD among incarcerated individuals is also important since the rate of SUD in this population far outpaces the general public. Only a small percentage of inmates with SUDs receive treatment. Laboratories that support testing for incarcerated individuals may consider collaborative efforts with correctional facilities or probation programs for SUD and STI screening and access to evidence-based treatment for individuals in the criminal justice system.¹⁵

Expanding access to STI care in the SUD population

STIs reported in the United States from 2011 to 2021 rose 42%. STI case counts began increasing in late 2020, perhaps due to increased healthcare utilization. In recent years, rates of STIs such as gonorrhea, chlamydia, HIV, and hepatitis A and C stabilized or slightly declined in some populations, yet the incident rate remains high.¹⁶ Effective STI control programs at state, local, and territorial health departments are essential to drive incidence and prevalence rates down across geographic regions and health disparity populations. These programs target STIs and SUD through surveillance, investigation, screening, prevention, outreach, diagnosis, case management, and education.

The CDC’s STI Prevention Priorities for 2022-2026 identified priority populations as adolescents and young adults, men who have sex with men (MSM), and pregnant women.¹⁷ Almost half of reported STI cases were adolescents and young adults between 15–24 years.¹⁸ Gay, bisexual, and MSM are disproportionately impacted by STIs, including gonorrhea and syphilis; co-infection with HIV is common.¹⁶ STI screening during reproductive years and pregnancy is essential for reducing acute and chronic disease for mother and baby. Many cases of STIs are not diagnosed or treated due to asymptomatic disease and lack of access to routine health care. Identifying at-risk populations and removing obstacles to care is a priority.

Syphilis

From 2019–2022, the rate of syphilis increased 57.2% across all stages: primary, secondary, tertiary, and congenital. During this time, the rate of SUD increased substantially among individuals with syphilis.¹⁹ The rate of new infections for all stages of syphilis slowed between 2022 and 2023, possibly due to increased awareness, reporting, updated screening and treatment guidelines, and implementation of automated reverse testing algorithms.^20,21

Historically, syphilis rapid plasma regain (RPR) has been used for screening and monitoring; RPR is a non-treponemal method. Automated treponemal serologic tests (e.g., EIA or CIA) are increasingly adopted, termed the reverse algorithm. CDC supports either algorithm and recommends positive screening results are confirmed by an alternative method.²⁰ Automated treponemal testing offers increased sensitivity for early syphilis, fast throughput, and lower costs. However, these tests should not be used for those with previous infection, as anti-treponemal antibodies may persist.

Primary and secondary syphilis and SUD

The rate of primary and secondary syphilis drastically increased since 2014. Implementation of guidance for testing and treatment may contribute to a slower incidence in the United States. The U.S. Preventive Services Task Force (USPSTF) recommends syphilis testing at least annually or more frequently (e.g., every 3–6 months) if high risk.²² The rate of primary and secondary syphilis decreased between 2022-2023 among both men (-11.9%) and women (-6.9%). Cases are more prevalent in males, especially among individuals 20–34 years. The largest percentage of primary and secondary syphilis were among MSM (32.7% overall; 44.2% among men). 41% of MSM with primary and secondary syphilis were also HIV positive.

Congenital syphilis

Syphilis during pregnancy can cause miscarriage, stillbirth, infant death, and lifelong medical issues. U.S. congenital syphilis cases increased tenfold over the past decade.²³ Barriers to timely congenital syphilis testing and treatment during pregnancy include lack of insurance, delays in seeking healthcare, geographic location, socioeconomic status, and SUD. In one study, women with syphilis who had congenital syphilis pregnancy outcomes had double the incidence of substance use than women with syphilis who did not pass it on congenitally.²¹ Increases in congenital syphilis cases were drastic between 2013 and 2022, but cases appear to be slowing in some areas since 2023, partly due to screening recommendations.²⁰

The most common missed prevention opportunity was lack of documented syphilis testing prior to or during pregnancy (42.5%), followed by no treatment or undocumented treatment (22.5%). Asymptomatic syphilis is possible. Having syphilis does not protect from reinfection; reducing risk is essential. These “missed opportunities” correspond to critical healthcare for syphilis in pregnancy, including timely screening and adequate treatment. Barriers are multifactorial and require focused, multi-stakeholder policy interventions. The National Syphilis and Congenital Syphilis Syndemic (NSCSS) Federal Task Force was established in 2023 to reduce rates of syphilis and health disparities.²¹ Linking syphilis patients with substance use disorders to behavioral health services and providing syphilis screening for persons receiving substance use disorder services are needed to address these co-occurring conditions.

HIV

Addressing substance use and SUDs is essential to reducing new HIV infections in the United States. by 90% by 2030 and ending the HIV epidemic. Those with HIV often face barriers, including stigma, discrimination, and the burden of managing a chronic condition. These challenges are compounded by co-occurring SUDs, which can adversely affect health outcomes and treatment engagement. Substance use behaviors such as injection drug use increase the risk of acquiring or transmitting HIV, impacting adherence to antiretroviral therapy, and perpetuating HIV transmissions. A whole-person approach is needed to expand HIV testing and reduce incidence and prevalence of HIV. A syndemic and status-neutral approach offers linkage to prevention services if negative or immediate connection to care if positive. Communities must screen, diagnose, treat, prevent, and respond near where people reside.

Hepatitis

Importance of regular STI screenings – HBV

Regular HBV screenings are crucial for individuals with SUD due to increased risk. Early detection leads to timely treatment, reducing severe complications and spread. In 2022, the CDC updated hepatitis B vaccination recommendations to promote universal vaccination in all adults ages 19–59 and adults over 60 with risk factors. In 2023, the CDC updated screening and testing recommendations to promote universal screening for all persons 18 and older at least once in their lifetime. CDC recommends screening all adults aged 18 and older for hepatitis B at least once using a triple panel test. Pregnant women should be screened during each pregnancy, and infants born to HBsAg-positive people should be tested.

For those unable to resolve HBV infection, two forms of chronicity can occur: non-replicative (better prognosis) and highly replicative. Seroconversion to HBe antibody indicates a move to the less risky state. Chronic HBV patients should be monitored for liver damage.

Importance of regular STI screenings – HCV

Hepatitis C virus (HCV) is a common viral hepatitis in the United States. More than half of HCV cases with risk information are associated with injection drug use. Many people with HCV do not know they have the virus. Early detection is essential for timely treatment and reducing complications and spread. HCV infection will spontaneously clear in about 25% of individuals, but many require drug therapy. Direct-acting antiviral therapies are expensive, and some payers require abstinence prior to treatment. However, current or prior substance use is not a contraindication to HCV treatment. Studies show individuals with SUD have excellent adherence and sustained virologic response.²⁴

There is no vaccination for HCV. Universal HCV screenings are CDC recommended for all adults 18 and older, all pregnant women during each pregnancy, and testing all infants and children born to pregnant women with hepatitis C. The CDC also recommends testing people in high-risk groups, including those with SUD, more frequently. Anti-HCV antibodies may not provide immunity against reinfection. Individuals with SUDs are at high risk for HCV due to high transmission rates in those who inject drugs.

Regular screenings provide opportunities for healthcare professionals to educate on safe sex practices and substance use treatment options, fostering a holistic approach to health and well-being.

Conclusions

The syndemic nature of SUDs and STIs is prevalent in the United States. The mental and physical health impact is substantial, potentially causing harm to self and others. Anyone is susceptible to SUD and is at increased risk of acquiring STIs. Syndemic and status-neutral approaches emphasize comprehensive care to engage and retain people in healthcare services in a dignified manner. Approaches that bridge prevention and treatment, minimize health inequities, help mitigate stigma, and provide whole-person care are necessary to support recovery. Clinical laboratories are essential for accurately identifying STIs and reporting urine drug test results to aid treatment and recovery.

References

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