Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) both cause common sexually transmitted diseases (STDs), with major public health consequences due to their frequent asymptomatic nature, the prevalence among adolescents, and their reproductive morbidity. Therefore, interrupting their route of transmission by identifying and treating patients with CT or GC is an essential intervention in the prevention of these STDs. Fortunately, present treatment protocols for CT and GC are based on 1-dose oral antibiotic therapy, resulting in successful compliance. Identification of infection is hampered by the limited compliance to undergo STD testing among adolescents and commercial sex workers (CSWs). Low compliance is caused by the partly nonspecific symptomatic and largely asymptomatic occurrence (CT approximately 70% and GC approximately 50% in women), the intimate gynecologic examination women have to undergo (traditional endocervical swab), the dispersion of most infections among young people in general, and the fact that most female adolescents do not feel at risk. Efforts to enhance willingness to test among at-risk youth are needed. New approaches within the laboratory diagnosis of CT and GC, like the highly sensitive and specific nucleic acid amplification tests (NAATs) using a self-taken vaginal swab (SVS) or first-catch urine (FCU), lead to easier specimen collection. These alternative noninvasive procedures initiate opportunities for public health enhanced active testing policies (active case finding) in order to encourage STD testing among adolescents at risk and CSWs.
Prior studies showed that self-obtained vaginal swab specimens were equivalent in sensitivity and reliability compared to traditional endocervical swab specimens and more sensitive and reliable than self-obtained urogenital specimen for the detection of CT and GC.1–8 The purpose of this study was to evaluate the acceptability and feasibility of SVS and FCU samples for the detection of CT and GC in young women attending a public health STD clinic.
Materials and Methods
Women that visited our public health clinic for STDs between August 2003 and August 2004 participated in the study. All participants signed an informed consent. The study population consisted of 16- to 35-year-old women. Refusal rate for SVS was low (1.5%; 6/419), with most frequent reason “current menstruation” (3/6); nobody refused FCU. Women who did not perform both tests were excluded; thus, a total of 413 young women were included. The average age was 23 (SD, 4.4). Ninety-six percent of the participants (397/413) had a Dutch background, 3 women were of Turkish/Moroccan origin, 2 were of Surinam/Antillean origin, and 11 persons were of European origin. Five percent (19/413) of them were CSWs. Most common reasons for their clinic visit (more answers possible) were prior risk behavior (56%), new sexual relation (21%), possible STD symptoms (vaginal discharge, vague symptoms, or not STD related at all) (20%), risk behavior partner (17%), and fear for possible acquired STD (9%).
All patients participated anonymously after signing the informed consent. Patients were given an individual code based on initials, sex, and date of birth. Patients were requested to leave a telephone number. An appointment at the clinic was made to inform the patient about the test results. In case of no response, STD nurses would call the patient. Before visiting the clinic, each participant was instructed by telephone not to urinate 2 hours before the FCU collection. Patients received instructions about how to take an SVS and FCU from educated STD nurses. The nurses used a checklist, a diagram, and demonstration material. Each patient was shown how to admit the vaginal swab—approximately 4- to 5-cm insertion and 30 seconds' vaginal rotation and rubbing time—and how to collect the swab into a capped tube. We also gave the patients a plastic container and asked them to collect 25 to 30 ml of first-void urine. SVS for NAAT was collected first, followed by the FCU specimen for NAAT. To verify our sampling procedure, a laboratory technician examined a sample of 100 swabs directly after receiving the swab, using a Gram-stained slide under the microscope (magnification 40×) to identify presence and amount of epithelial cells. When all 100 samples were checked and confirmed as “much” (5–10 cells per field) to “very much” (more than 10 cells per field) vaginal epithelial cells, this quality procedure was ended.
All patients received a questionnaire concerning demographic data (sex, age, ethnic background), reason(s) for STD examination, sexual preference, previous STD examinations, prior STDs, being a CSW, reasons for choosing the public health clinic, acceptability of both methods, patients' preferable examination method, and evaluation of the STD consultation.
Patients who tested positive for CT were treated with 1 dose of 1000 mg azithromycin, and those who tested positive for GC, with 1 dose of 500 mg ciprofloxacin as quinolone resistance in our region is low. In case GC symptoms did not disappear within a few days, an additional vaginal sample was taken for GC culture to evaluate antibiotic resistance. If possible, sexual relations of the last 6 months were treated as well.
SVS and FCU samples were tested for the presence of CT and GC by a NAAT with internal inhibition control (strand displacement amplification assay [SDA], Becton Dickinson ProbeTec ET system, MD). For SVS testing, the standard swab protocol was used as provided by the manufacturer because testing SVS is similar to testing swabs taken by a physician. A positive result for CT (more than 10,000 DNA copies) was labeled as positive test. All low-positive samples with between 2000 and 9999 copies of CT DNA would also be retested to confirm presence of CT (in our data, this did not occur).9 All positive samples for GC were retested to minimize false positivity.9 When the second test was negative, the sample was registered as no GC infection (in our data this occurred in 4 samples). All inhibited samples (amplification control) were retested (in our data this occurred only once). If they could not be confirmed afterward, a new sample would be asked from the participant for retesting (in our data, this did not occur). If the test result was positive in one of the samples, a woman was considered to be infected.
We compared test results from SVS and FCU specimens, focusing on the analysis of percent agreement between results of both methods. All participants were also tested for syphilis, hepatitis B, and human immunodeficiency virus, but none tested positive.
Analysis was performed with the SPSS package version 12.0.1 (SPSS, Inc., Chicago, IL). Prevalences were calculated with 95% confidence intervals. Differences in characteristics between participants were analyzed using chi-square or Fisher exact test. Associations between unadjusted prevalence and several characteristics were assessed by univariate and multivariate logistic regression analyses.
STD Prevalence and Test Performance
Of all participants, 11.9% (49/413) were diagnosed with CT and/or GC. In our study population, CT infection was the most prevalent STD, 10.9% (45/413) compared to GC-infection, 1.5% (6/413). Two patients were diagnosed with both infections. In the lowest age groups, CT prevalence was highest: between 16 to 20 years 12% (16/131) and 21 to 25 years 13% (23/181). Also, all GC infections occurred in these age groups. Between 26 to35 years, CT prevalence was 6% (6/101). Participants who had a prior STD (CT, GC, or syphilis) had higher prevalence of CT, 19% (8/43), versus those who never had an STD diagnosed before, 10% (35/361). More confirmed positive test results were found when using SVS compared to using FCU (see Table 1). The percent agreement of both tests is 98.9% (408/413) for CT and 99.3% (410/413) for GC (see Table 1).
Public Health STD Clinic
Seven out of 10 women (68%) who came to the public health STD clinic were never tested for STD before and probably would not have been tested without this kind of public health care being available. However, about 11% of these women (30/282) tested positive for CT and/or GC. More than 12% (51/413) mentioned “not having to undergo intimate traditional gynecologic examination” as one of the reasons to go to the public health STD clinic. Other important reasons were anonymity/privacy (68%), easy access (61%), pleasant treatment (26%), expertise staff/quality diagnosis (23%), good information (21%), recommended by friends (19%), and short waiting time (14%).
Results of the evaluation questionnaire on SVS and FCU are largely positive. All patients felt confident about their capability to perform the SVS and FCU (see Table 2). The instruction given to the patients was clear according to 97% for SVS and 93% for FCU. Self-collection of vaginal swabs was almost uniformly reported as easy to perform (95%). The same is true for FCU: 92% reported it was easy to perform. The vast majority was positive about self-collection of urine samples and vaginal swabs. Although almost 2 out of 3 women reported that they liked the fact the FCU was not gynecologic examination, only 9 women (2%) found the SVS unpleasant. Even less reported the FCU as unpleasant, namely 5 (1%). Most of the women would choose to take SVS (90% agree; 9% neutral) or FCU (94% agree; 5% neutral) again if necessary. Just 2% and 1%, respectively, would rather not take SVS or FCU again. Self-collection of urine samples and vaginal swabs are preferred (77%) above a gynecologic examination (0.2%); 23% did not voice a preference (see Table 3). None of the women who had an invasive STD examination at least once before (13%; 54/413) preferred the swab to be taken by an STD nurse or physician. This is a significant outcome because this group is able to compare experienced invasive testing performed by a nurse or physician to the SVS.
Prompt recognition and appropriate treatment of STDs play a key role in controlling their transmission. Because many STDs have common symptoms or remain asymptomatic, they often stay undiagnosed and untreated. Accurate, cost-effective, reliable, accessible, and feasible diagnostic assays are needed to decrease their prevalence. Reluctance of at-risk populations to attend appropriate care and fear of invasive gynecologic examination hamper effective STD control. Self-collected noninvasive specimens like SVS and FCU can play a role in optimizing control of STD. Other advantages of these tests are high sensitivity and the fact that no viable organisms are required, less critical transport and storage conditions are needed. This is especially true for GC culture, which normally requires a special transport medium and quick inoculation because bacterial counts are reduced by 80% after 6 hours and by 99% after 24 hours.10 Our study showed the feasibility of these tests and dealt with critical drawbacks from other studies like strict protocol for sampling SVS and FCU, a NAAT with inhibition control, check on SVS sampling procedure with microscopy, and double testing for positive results. Our nonresponse was low (1.5%), suggesting low bias affects the results. One of the main limitations of our study is that it was not compared to the acceptability of experienced gynecologic examination.
Both diagnostic techniques should be used to have maximal sensitivity because SVS and FCU showed about 1% discrepancy in our population with 11% CT and almost 2% GC. Our study showed more confirmed CT and GC for SVS specimens than for FCU (see Table 1). These results are similar to the results of other studies, 6–8 such as a multicenter study with specimens from 2517 15- to 25-year-old asymptomatic women attending different clinics demonstrates.7 In that study, NAAT sensitivity with SVS (93%) was as high as or higher than NAAT sensitivity with gynecologic swabs taken by physician (91%) or FCU (81%) or culture of cervical swabs (83.5%). Another study compared a modified sanitary napkin with traditional gynecologic swab and FCU from 510 women at medical or community settings with Roche PCR.11 In that study, testing results on paired samples were identical for slightly fewer participants as in our study (96.6%), with a comparable CT prevalence (11.3%), with best results for the FCU (sensitivity 100%, ppv 100%; npv 98%). Prior studies showed that SVSs have equivalent sensitivity and reliability as traditional endocervical swab specimens. 1–5 Therefore, we can convincingly conclude that SVS and, to a lesser extent, FCU too are appropriate specimens for diagnosing chlamydial and gonococcal genital tract infection by NAATs. To save costs, they could be sampled as 2 separate sites and tested as 1 diagnostic sample.
Acceptability and Feasibility
Easy acceptable tests not requiring a speculum can provide a strong base for young women complying with STD testing. Therefore, the testing method can play a role in the decision-making process of young women. Using SVS and/or FCU might take away some of the reasons not to get tested. In our study, 68% of the female participants never previously had an STD examination, of whom 11% tested STD positive. More than 12% of the included patients mentioned “not having to undergo intimate gynecologic examination” as one of the main reasons to go to the public health STD clinic. Self-collection through SVS and FCU was easy to perform and preferable (77%) above a traditional gynecologic examination (0.2%). None of the women who had a gynecologic STD examination before preferred the swab to be taken by an STD nurse or physician. Using SVS (with or without FCU) can be an important enhancing tool in public health care to encourage young women to get tested for STDs. However, although most of the participants knew about our testing policy, we do not know how many would have come anyway when traditional gynecologic examination was offered. The traditional policy in our public health STD clinic is to not perform a gynecologic examination. Nevertheless, we can convincingly conclude that using SVS and FCU has a high feasibility and acceptability, enabling the detection of CT and GC that would otherwise remain undiagnosed and untreated.
Other studies underscore our conclusions, although different study populations and evaluation methods were used.7,12–17 One study determining the feasibility and acceptability of SVS among 228 female high school students (15–19 years) with CT prevalence of 8% and GC prevalence of 2% gave similar results as our study.11 Nearly 13% of women in that study who had never previously had a gynecologic examination tested positive for an STD. This is a similar finding compared to 11% in our study. They found that 51% of infected students would not have pursued testing by traditional gynecologic examination if self-collection were not offered. Nearly all (97%) stated that they would undergo testing at frequent intervals if self-testing were available.12 SVS and FCU for STD testing can be easily implemented in STD clinics but also in nonclinical settings. This has allowed detection of CT and GC in difficult-to-reach populations. An American study ascertained the acceptability of SVS versus traditional endocervical swab in 512 black adolescent girls in a nonclinical program, with CT prevalence of 17.8% and GC, 5.3%.13 All eligible participants chose SVS. Another American study determined the utility of FCU in 46 female adolescent detainees with a CT prevalence of 28% and GC, 13%.15 FCU was a useful tool in identifying and guiding treatment of unsuspected GC and CT infections in this nonclinical setting.
FCU was only slightly preferred above SVS in our study. A study among 1382 US military women with a CT prevalence of 12% tested with LCR showed high acceptability for both tests, although FCU was significantly preferred (79%) above SVS (69%) in the future.17 In this study, most women (60%) reported that FCU was the easier method. Preference for SVS was associated with being white and having had sexual risk behavior in the past 3 months.17 In our study among mainly Dutch women, the difference in preference was not strong, which may imply that selection of self-collected sampling should be made according to cultural background of the population. If only 1 sampling method is chosen, SVS should be the first choice because, based on our data, it has the highest sensitivity and a high acceptability. SVS being at least as good as physician-obtained endocervical swabs, this method can be used in different clinical and nonclinical settings. Both SVS and FCU are acceptable in this population. However, for transport purposes (via post or other), SVS is preferred because it is less likely to leak. In addition, swab processing is less labor intensive than an FCU specimen. Also, self-obtained samples are essential when using home-sampling kits for STD screening.18 Because these kits are sent by mail, SVS is preferred.
CT and GC are prevalent among young women, yet willingness to undergo traditional gynecologic STD testing is limited. Efforts to enhance compliance with testing among at-risk women are needed. SVS and FCU are appropriate specimens for highly sensitive STD diagnosis. SVS and FCU are well accepted and feasible among this risk group. These easy sampling methods should therefore be used in clinical and nonclinical settings, being a new opportunity in STD control to increase STD testing coverage among young women.
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