Summertime means more sunshine, more socializing, and, according to medical researchers, more sexually transmitted infections (STIs). A new study by telehealth company Invigor Medical analyzed data from the Centers for Disease Control and Prevention (CDC) to determine how infection rates have evolved across the United States, and which states and cities have the highest rates of reported STIs.Examining the four most commonly tested STIs chlamydia, gonorrhea, syphilis, and HIV, the study tracked how rates have changed over time, and where the infections are most concentrated in the U.S. According to the study, the overall number of reported STIs has increased in the U.S. since 2013, when 1.8 million cases were reported. In 2023, that number rose to 2.5 million cases, with chlamydia being the most common STI, with more than 1.6 million new cases reported that year.Despite the rising number of reported STIs, the study actually notes that the STI epidemic is slowing down. "While Syphilis infections remain at record highs, reported cases of Chlamydia, Gonorrhea, and HIV have declined from their peak levels in previous years, signaling a promising shift in the trajectory of the nations STD burden," the study's analysis reads. See on Instagram This overall slowdown could be due, in part, to the growing adoption of prevention methods like PrEP and sex education resources. However, states that have fewer prevention efforts report higher numbers of new infections. The study notes that many of the states with higher infection rates are concentrated in the South. "These states tend to face persistent challenges in STD prevention, including gaps in healthcare access, limited sexual health education, and structural barriers to screening and treatment," the study reads. "Outside of the Southern U.S., South Dakota and New York also report relatively high rates despite different demographic and policy contexts."The study found that South Dakota reported several concentrated outbreaks in Native American communities, which are often impacted by systemic inequity in health care and limited access to services and education. By contrast, the study notes that in New York, there's a higher concentration of at-risk populations (including but not limited to gay and bisexual men, and trans folks), and more robust surveillance and tracking methods, which can lead to higher numbers of cases being reported.States with the lowest infection rates were concentrated in New England, the study reports. "Vermont (241.0), New Hampshire (251.1), and Maine (276.6) sit at the bottom of the list, with rates less than one-fourth of those in the highest-burden states," Invigor Medical writes. "New England states tend to be older and have less ethnic diversity, both of which are associated with lower STD risk. Additionally, the region has higher median household incomes and lower uninsured rates, making it easier for residents to access testing and treatment and thus reducing the rate of spread."