Possible explanations for the increased incidence in chlamydia, gonorrhea, and syphilis include improved technology, which may contribute to the number of cases reported. Before 2002, diagnostic testing for chlamydia and gonorrhea was performed via culture. Bacterial culture presented significant difficulty with maintaining viability of organisms during transport, as well as difficulty with test standardization, high costs, and relative insensitivity of the test. This lack of efficacy prompted the development of nonculture tests, including enzyme immunoassays, direct fluorescent antibody tests, and nucleic acid hybridization tests. However, each of these tests failed to detect a significant number of infections. The development of nucleic acid amplification tests resulted in a new criterion standard for chlamydia and gonorrhea testing, as it is 20% to 35% more sensitive than the preceding nonculture tests.⁴ 

Another contributing factor may be the low prevalence of condom use.⁵ Every 5 years, the CDC performs a national survey asking men and women aged 15 to 44 years whether they used a condom during their most recent sexual intercourse in the past 12 months. A 2017 report comparing data from the 2006-2010 survey with data from the 2011-2015 survey found that the percentage of women who used a condom decreased from 25.3% to 23.8% over time, and the percentage of men remained stable (33.1% vs 33.7%).⁵ Condom use rates of 23.8% and 33.7% are alarmingly low given their established role in preventing the spread of STIs. 

With the increase in the 3 aforementioned STIs, there is a paradoxical decrease in funds available for STI screening. State and local STI programs continue to have budget cuts, with 52% of programs being cut and 21 clinics closing in 2012.² Fortunately, funding for STI prevention has increased. The fiscal year 2019 budget acknowledges the recent increase in chlamydia, gonorrhea, and syphilis and includes $152 million to fund the surveillance, prevention, and control of STIs. This is a $1 million increase from the amount allocated in the fiscal year 2018 budget.⁶ 

Another potential explanation for the increased rates is poor sexual history taking and STI screening by health care professionals. The failure to detect STIs early could result in further propagation and spread of infections, as well as more long-term complications of these infections. A 2005 survey⁷ of US medical schools and fourth-year medical students revealed that only 55.4% of schools surveyed had a sexual health curriculum. When asked about their comfort level in taking a sexual history, the students were most likely to be comfortable with patients aged 15 to 24 years (91%) and 25 to 50 years (93%) than with patients aged 10 to 14 years (57%), 51 to 75 years (67%) or older than 75 years (50%).⁷ The students were also given case scenarios and asked whether they would screen each patient for chlamydia. Most students correctly chose to screen a 31-year-old pregnant woman (94%) and a sexually active 20-year-old woman (74%).⁷ Forty-seven percent said that they would screen a 20-year-old man who had oral sex with another man.⁷ This information indicates room for growth in sexual health education in medical school, including sexual history taking and STI screening. 

Although chlamydia, gonorrhea, and syphilis can all be managed with antibiotics, dire consequences can result when these STIs are left undiagnosed and untreated. Infertility, ectopic pregnancy, stillbirth in infants, potentially fatal neurologic and cardiovascular complications, and increased risk for HIV transmission are potential medical complications that can result from untreated infections. Additionally, the stigmatization of subgroups of people in the United States who are disproportionately infected is of concern, including the MSM population, African Americans, and American Indians/Alaska Natives.² 

Antimicrobial resistance of N gonorrhoeae is a growing concern in the medical community. Between 2013 and 2016, the rate of azithromycin resistance increased from 0.6% to 3.6%.² Within 10 years, cephalosporin-resistant N gonorrhoeae could cause an estimated 75,000 additional cases of pelvic inflammatory disease, 15,000 cases of epididymitis, and 222 cases of HIV, which would cost $235 million in direct medical costs.⁸ 

Financially, the rise in STIs is of great concern. In 2016, the total lifetime direct medical cost of treating 8 of the most common STIs contracted in a single year was $15.6 billion. This figure included $516.7 million for chlamydia, $162.1 million for gonorrhea, and $39.3 million for syphilis.⁹ Due to inflation and the increase in cases in the past 10 years, these numbers will likely continue to rise. 

In 2015, the CDC published their STD screening and treatment guidelines.¹ In general, these guidelines have the following screening recommendations. 

All nonpregnant sexually active female patients younger than 25 years should be screened for chlamydia and gonorrhea. Women older than 25 years and at increased risk for infection may also be screened. Patients with a diagnosis of chlamydia or gonorrhea should be rescreened 3 months after treatment is completed. There are currently no guidelines for screening nonpregnant females for syphilis. 

All pregnant patients younger than 25 years (or >25 years and at increased risk) should be screened for chlamydia and gonorrhea at the first prenatal visit, with repeated chlamydia screening in the third trimester. Pregnant patients with a chlamydia diagnosis should be rescreened 3 to 4 weeks after treatment and again 3 months later. Pregnant patients with a gonorrhea diagnosis should be rescreened 3 months after treatment. All pregnant patients should be screened for syphilis at the first prenatal visit, with repeated screening early in the third trimester and at delivery if at high risk. 

Male patients should be screened for chlamydia if they are located in high prevalence clinical settings or are part of a population with a high burden of infection, regardless of age. Men who have sex with men should be screened for chlamydia, gonorrhea, and syphilis at least annually (every 3 to 6 months if at increased risk), regardless of condom use. 

Sexually active males and females who are HIV positive should be screened for chlamydia, gonorrhea, and syphilis at their first HIV evaluation and at least annually thereafter. 

The Table outlines the CDC's diagnosis and treatment guidelines.¹ Partners should be encouraged to seek evaluation and to discuss screening for other STIs with a health care professional. The American College of Obstetricians and Gynecologists advocates for expedited partner therapy as a method of preventing gonorrhea and chlamydia reinfection when a patient's partners are unable or unwilling to seek medical care. Expedited partner therapy should only occur after a health care professional has assessed the risk of intimate partner violence associated with partner notification.¹⁰ Expedited partner therapy is currently prohibited in 2 states (Kentucky and South Carolina) and limited in 7 states (Alabama, Delaware, Kansas, Oklahoma, New Jersey, South Dakota, and Virginia) and Puerto Rico.¹¹ 

Physicians and medical students have a duty to educate themselves and their patients about STIs. Familiarization with the prevention, screening, diagnosis, and treatment guidelines for STIs is essential. But it is also important to recognize the variety of STI presentations and the multitude of both acute and chronic complications that occur with unrecognized or untreated cases. 

The National Coalition for Sexual Health recommends that a sexual history be taken for all teenagers and adults at least annually.¹² Topics to consider addressing include the 5 Ps: partners, practices, past STI, protection, and pregnancy prevention. When taking a sexual history, physicians should use neutral terms (eg, partner) and avoid making assumptions about a patient's sexual behaviors, sexual orientation, or gender identity.¹² 

Sources of additional STI training and education include the National Network of STD Clinical Prevention Training Centers¹³ and the CDC.¹⁴ Cardea Services has a sexual history–taking toolkit, which includes a comfort scale self-assessment, sample history forms, and a pocket guide.¹⁵ 

Advocating for funding for affordable STI screening and treatment programs at the state or national level is important, particularly for patients in underserved areas. Additionally, advocating for expansion of expedited partner therapy would be of benefit to potential infected partners and would help reduce the spread of STIs. 

The rates of chlamydia, gonorrhea, and syphilis infections are alarmingly high. These STIs can cause grave medical consequences for affected persons, especially when the STIs are undiagnosed and untreated. It is imperative that health care professionals perform thorough sexual histories, be familiar with STI presentations, enact routine screening for STIs in sexually active patients, and provide patient education. By remaining proficient in the current diagnosis and treatment guidelines and committing to continuing education, they can play a role in reversing this alarming trend in the United States.