Executive Summary
Data from a recent study that looked at more than 10,000 people who attended a Baltimore public health clinic indicate the occurrence of gonorrhea or chlamydia in extragenital areas such as the throat or rectum is significant in women, particularly younger women.
- Current public health guidelines call for routine screening for extragenital gonorrhea and chlamydia in men who have sex with men and people with HIV, given the high burden of these sexually transmitted infections in these at-risk populations.
- However, there are no current recommendations to routinely screen women at extragenital sites.
Data from a recent study that looked at more than 10,000 people who attended a Baltimore public health clinic indicate the occurrence of gonorrhea or chlamydia in extragenital areas such as the throat or rectum is significant in women, particularly younger women.1
Researchers from Johns Hopkins University School of Medicine in Baltimore looked at health records from 10,389 people (4,402 women, 5,218 heterosexual men, and 769 men who have sex with men [MSM]) who visited the Baltimore City Health Department Eastern Health District or the Druid STD Clinic between June 2011 and May 2013. All of the people included in the study had reported recent exposure to oral and/or anal sexual intercourse.
Current public health guidelines call for routine screening for extragenital gonorrhea and chlamydia in MSM and people with HIV, given the high burden of these sexually transmitted infections (STIs) in these at-risk populations. However, there are no current recommendations to routinely screen women at extragenital sites.
When infections from gonorrhea and chlamydia occur in extragenital areas, they are typically asymptomatic, said Joshua Trebach, a third-year student at the Johns Hopkins University School of Medicine in a press statement accompanying the research publication. “These types of infections pose a large and hidden public health threat, because they can be transmitted to unwitting sexual partners and form an active infection,” he noted.
Screening cost-effective?
If the women examined in the Johns Hopkins University study had received only genital STI tests, nearly 14% of chlamydia infections and more than 30% of gonorrhea infections would have been missed. Researchers found the total prevalence of extragenital gonorrhea or chlamydia among the more than 4,000 women screened was 2.4% and 3.7%, respectively. By comparison, the extragenital rates for MSM were 18.9% for gonorrhea and 11.8% for chlamydia.
While the prevalence of extragenital gonorrhea and chlamydia is highest in MSM, a significant number of gonorrhea and chlamydia infections in young women would be missed with genital-only testing, researchers note. Cost-effectiveness analyses are needed to help inform national guidelines on extragenital screening in young women, they state.
To understand the cost effectiveness of screening women for extragenital infections, first there needs to be an understanding of how such infections impact reproductive health in women, says one of the research paper co-authors, Khalil Ghanem, MD, PhD, associate professor of medicine at the University. By not detecting and treating these infections, what is the impact on the likelihood of transmission to male partners and the probability that these male partners will transmit the infection to their female partners in the genital tract, leading to poor reproductive outcomes?
“This seems like it would be a rare occurrence, but on a population level, it might not be so rare,” notes Ghanem.
3 questions
The issue goes to the questions of the role of extragenital infections in driving the prevalence of Neisseria gonorrhoeae and Chlamydia trachomatis in a population, how these infections impact HIV transmission/acquisition in women and their sexual partners, and how these infections contribute to the emergence of resistance, says Ghanem. These questions are particularly important for gonorrhea, as it is believed that pharyngeal infections are the source of many, if not most, resistant mutations.2
“None of these questions have easy answers,” observes Ghanem. “Ideally, the next step is to try and develop models to help gauge the potential impact of extragenital infections on reproductive outcomes, HIV acquisition/transmission, and emergence of resistance.”
Such action might be easier said than done because researchers will have to input variables in a model.” Because many of these variables are not known, and cannot be easily extrapolated from a clinical setting, such research presents “a very big challenge,” notes Ghanem.
Screening is important
In MSM, most of the screening benefit comes from HIV acquisition/transmission reduction that comes with extragenital screening, Ghanem comments. This reduction is why extragenital screening is recommended in this population, he notes.
Gonorrhea and chlamydia are much more prevalent in the MSM population than in the heterosexual population. Data from a review of 42 U.S. clinics show extragenital gonorrhea and chlamydia was common among MSM attending STI clinics.3 As such, the impact is much greater and can be quantified, says Ghanem.
“Most of the impact in women would have to come from how these infections impact reproductive health,” Ghanem states. “That’s a big unknown.”
- Trebach JD, Chaulk CP, Page KR, et al. Neisseria gonorrhoeae and Chlamydia trachomatis among women reporting extragenital exposures. Sex Transm Dis 2015; 42(5):233-239.
- Weinstock H, Workowski KA. Pharyngeal gonorrhea: An important reservoir of infection? Clin Infect Dis 2009; 49(12):1798-1800.
- Patton ME, Kidd S, Llata E, et al. Extragenital gonorrhea and chlamydia testing and infection among men who have sex with men — STD Surveillance Network, United States, 2010-2012. Clin Infect Dis 2014; 58(11):1564-1570.
