Screening and treatment of sexually transmitted infections (STIs) can cost states tens of millions of dollars in Medicaid budgets, but public health activities to prevent STIs can help reduce these costs, according to a new study.1

Contraceptive Technology Update asked researcher Melinda A. Merrell, PhD, MPH, research assistant professor in the Rural & Minority Health Research Center at the University of South Carolina, to discuss her study’s findings and implications. This interview has been edited lightly for length and clarity:

CTU: What do your findings suggest about the cost of diagnosing and treating STIs? How might it compare to the cost of investing in public health prevention efforts?

Merrell: Our findings suggest that diagnosis and treatment of the most commonly reported STIs does financially impact individual state Medicaid programs. While we were unable to provide a direct cost comparison between expenditures for Medicaid programs vs. public health prevention activities, we know that primary prevention and improved access to STI services can reduce the burden of these diseases, thus reducing costs overall.

CTU: Which STIs were included in the analysis? How common are those infections in the states you studied, and in the United States?

Merrell: Chlamydia, gonorrhea, and syphilis were chosen for this study due to their overall prevalence in the United States as well as increasing trends in cases since 2014. As of 2018, the national prevalence of chlamydia was 1.8 million cases (a 14% increase since 2014); gonorrhea, 583,405 cases (63% increase); and primary and secondary syphilis, 35,063 cases (71% increase). By state in 2018, Maryland had 35,482 chlamydia cases, 10,305 gonorrhea cases, and 2,536 syphilis cases. South Carolina had 33,910 chlamydia cases, 13,801 gonorrhea cases, and 1,152 syphilis cases.2-4

CTU: Why did you choose to compare South Carolina with Maryland? What difference in Medicaid expenditures for STI care did you find between these two states?

Merrell: We wanted to examine differences in Medicaid expenditures between two states. Currently, one of the biggest differences we can observe in Medicaid programs is whether access to coverage was expanded to people with incomes up to 138% of the federal poverty line as a result of the Patient Protection and Affordable Care Act (ACA). Maryland and South Carolina had similar rates of Medicaid participation and STI prevalence but differed on Medicaid expansion, which made them ideal for this comparison. Maryland expanded Medicaid eligibility under the ACA in 2014; South Carolina has not yet exercised this option.

We found that STI screening and treatment in Maryland was performed in higher numbers and at a higher total expenditure to the Medicaid program as compared to South Carolina. This was in spite of the observation that most services provided for STI care in South Carolina occurred in a high-cost setting (the emergency department).

Maryland Medicaid spent $41.5 million in state fiscal year (SFY) 2016 and $45.4 million in SFY 2017, while South Carolina Medicaid expenditures were $22 million in SFY 2016 and $22.6 million in SFY 2017. The highest cost setting for Maryland Medicaid was the outpatient hospital setting ($26.4 million in SFY 2016 and $27.4 million in SFY 2016).1

These findings suggested that differences in Medicaid eligibility between the two states as well as the design of the healthcare delivery system in Maryland, among other factors, may have increased access to STI services for Maryland Medicaid participants.


  1. Merrell MA, Betley C, Crouch E, et al. Screening and treatment of sexually transmitted infections among Medicaid populations — a two-state analysis. Sex Transm Dis 2021. doi: 10.1097/OLQ.0000000000001365. [Online ahead of print].
  2. Centers for Disease Control and Prevention. 2018 STD surveillance report highlights alarming threat: Newborn deaths from syphilis. Page last reviewed Jan. 25, 2021.
  3. Janney E. STD rates reach another record high in MarylandPatch. Oct. 10, 2019.
  4. Centers for Disease Control and Prevention. Sexually transmitted disease surveillance 2018. Page last reviewed Aug. 20, 2019.