Summer travel comes with heightened health risks. According to multiple studies, sexually transmitted disease rates spike during warmer months due to increased social activities and risky behaviors. 

LabCafe analyzed the riskiest travel destinations across the US to compare socioeconomic indicators and STD rates per capita, ranking each destination.

Which US travel destination has the highest risk of STDs?

STI-Risk Score: What It Measures

To better capture the multifaceted risks travelers face, we introduce a  STI-Risk Score for U.S. counties, scaled from 0 to 100. This metric merges two pillars:

• STI Infection burden: county rates for chlamydia, gonorrhea, syphilis, and new HIV diagnoses.
• Socio-economic vulnerability: poverty, low education, lack of insurance, and vacant-housing share.

The national mean is approximately 9.9; scores above this threshold signal environments where travelers are more likely to encounter higher-than-average STI exposure or significant barriers to care.

The twenty highest-volume U.S. tourism metros (by 2023 international arrivals) show wide variation in average county risk:

Miami and Fort Lauderdale have the two highest risk scores from top tourist destinations. The top 7 metropolitan areas with the most tourists all have higher risk scores than the national mean. 

Risk Score at the County Level

Source: Analysis by LabCafe, CDC NCHHSTP Atlas

Top 5 Highest Risk Counties:

• Oglala Lakota, SD (Risk score = 65)
• Buffalo, SD (60)
• Todd, SD (54)
• Dewey, SD (52)
• Sioux County, ND (41)

These are all remote Tribal counties with high STI burdens and deep socio-economic barriers.

Bottom-5 Lowest Risk Counties:

• Ozaukee, WI (Risk score = 2.5)
• Los Alamos, NM (2.5)
• Morgan, UT (2.6)
• Hunterdon, NJ (2.7)
• Carver, MN (2.7)

These are predominantly well-off suburban or small rural counties with excellent insurance coverage and some of the lowest STI case rates in the nation.

Counties with the Highest and Lowest STI-Burden

Top-5 STI-Burden:

• Oglala Lakota, SD (67)
• Buffalo, SD (66)
• Dewey, SD (62)
• Todd, SD (60)
• Sioux, ND (42)

States with the Most STD Risk Counties

• Mississippi (18 counties)
• Georgia (12)
• South Dakota (10)
• Texas (7)
• Alaska (7)  
• South Carolina (7)
• North Carolina (5)
• Louisiana (5)
• Montana (4)
• Alabama (4)
• Virginia (4)

Score Results for Every County

The risk score reveals two clear risk clusters: busy coastal metros like Miami, Fort Lauderdale, and Los Angeles, where large visitor volumes meet elevated STI rates, and remote Tribal counties on the Northern Plains, where extreme infection levels align with deep socio-economic barriers. Travelers therefore need targeted STI-prevention guidance in both tourism hot-spots and underserved rural areas.

Methodology

Data sources

• U.S. figures came from the CDC’s 2023 STI  surveillance tables. Each line gives one pathogen-specific rate (chlamydia, gonorrhea, primary & secondary syphilis, or new HIV diagnoses) for a state or territory.
• County-level microdata:CDC NCHHSTP Atlas.
• Tourism demand International-arrival counts by U S city: International Trade Administration “U.S. States & Cities Visited by Overseas Travelers” .
• HealthTrackRx. (2024). STI Tests: Understanding Seasonality and Patterns.

County composite risk score 

• Gather four pathogen rates per county (chlamydia, gonorrhea, primary + secondary syphilis, new HIV) and four ACS percentages (poverty, no-HS diploma, uninsured, vacant housing).
• Min-max scale each variable to 0–100 so the lowest county becomes 0 and the highest becomes 100.
• Infection burden = average of the four scaled pathogen measures.
   Socio-economic strain = average of the four scaled structural measures.
• Combine with a 2-to-1 weight:
   Risk=0.67×Burden+0.33×StrainRisk=0.67×Burden+0.33×Strain
• National mean ≈ 9.9; scores above that signal elevated exposure or barriers to care.

Metro aggregation

• Use 2023 OMB delineations to group counties into MSAs or metropolitan divisions.
• Take the simple mean of member-county risk scores to assign a metro score.
• Append 2023 overseas-visitor totals to spotlight high-traffic destinations.