Thomas A. Peterman

Reducing the risk of sexual HIV transmission: quantifying the per-act risk for HIV on the basis of choice of partner, sex act, and condom use.

Background Sexual acquisition of HIV is influenced by choice of partner, sex act, and condom use. However, current risk-reduction strategies focus mainly on condom use. Goal To estimate the contribution of choice of partner, sex act, and condom use on the per-act relative and absolute risks for HIV infection. Study Design Per-act relative risk for HIV infection was calculated with use of estimates of HIV prevalence, risk of condom failure, HIV test accuracy, and per-act risk of HIV transmission for different sex acts. Absolute risks were calculated on the basis of these relative risk estimates. Results Choosing a partner who tested negative instead of an untested partner reduced the relative risk of HIV infection 47-fold; using condoms, 20-fold; and choosing insertive fellatio rather than insertive anal sex, 13-fold. Choosing one risk-reduction behavior substantially reduces absolute risk of HIV infection for heterosexuals but not for men who have sex with men. Conclusion Clarifying the magnitude of risk associated with different choices may help people make effective and sustainable changes in behavior.

Does measured behavior reflect STD risk ? : An analysis of Data from a randomized controlled Behavioral intervention study

Background: Many studies measure sex behavior to determine the efficacy of sexually transmitted disease (STD)/HIV prevention interventions. Goal: To determine how well measured behavior reflects STD incidence. Study Design: Data from a trial (Project RESPECT) were analyzed to compare behavior and incidence of STD (gonorrhea, chlamydia, syphilis, HIV) during two 6‐month intervals. Results: A total of 2879 persons had 5062 six‐monthly STD exams and interviews; 8.9% had a new STD in 6 months. Incidence was associated with demographic factors but only slightly associated with number of partners and number of unprotected sex acts with occasional partners. Many behaviors had paradoxical associations with STD incidence. After combining behavior variables to compare persons with highest and lowest risk behaviors, the STD incidence ratio was only 1.7. Conclusion: Behavioral interventions have prevented STD. We found people tend to have safe sex with risky partners and risky sex with safe partners. Therefore, it is difficult to extrapolate the disease prevention efficacy of an intervention from a measured effect on behavior alone.

High Incidence of New Sexually Transmitted Infections in the Year following a Sexually Transmitted Infection: A Case for Rescreening

Context The Centers for Disease Control and Prevention recommends that women treated for Chlamydia trachomatis infection return in 3 months for evaluation of reinfection. Contribution When data from the RESPECT-2 trial were used, these investigators found that among patients treated for sexually transmitted infections, 25.8% of women and 14.7% of men acquired 1 or more new infections with Chlamydia trachomatis, Neisseria gonorrhoeae, or Trichomonas vaginalis during 1 year of follow-up. Approximately 66% of reinfections were asymptomatic. Implications Successful treatment of incident cases of sexually transmitted infections is unlikely to eliminate a reservoir of infection in the community. Physicians need to perform ongoing surveillance on men and women and encourage lifestyle changes in patients with reinfection. The Editors In 1985, the Centers for Disease Control and Prevention (CDC) treatment guidelines recommended that persons infected with Neisseria gonorrhoeae should return for a test of cure to be sure that the antibiotics had cured the infection (1). With new medications, treatment failure became rare, and by 1989, the guidelines suggested testing 1 to 2 months after treatment to detect treatment failure and reinfection (2). By 1993, the guidelines stated only that a test of cure was not recommended for N. gonorrhoeae (3). Test of cure has been unnecessary for Chlamydia trachomatis after treatment with first-line drugs, but infections detected among women several months after treatment have suggested that rescreening might be effective for detecting reinfection (3). Recent studies have found that 11% to 15% of women treated for C. trachomatis were infected when retested 3 to 4 months after treatment, possibly due to treatment failure, reinfection from an untreated partner, or infection from a new partner (46). New infections are often asymptomatic. One study with scheduled follow-up visits found that 62% of new C. trachomatis infections in men and in women were asymptomatic or unrecognized and would therefore probably be missed without rescreening (7). Untreated C. trachomatis infections can persist for years (8) and put infected women at risk for complications of asymptomatic pelvic inflammatory disease (9). In addition, transmission from asymptomatic persons may be responsible for most new infections in a community (10). The CDC has recommended that health care providers consider advising women with diagnoses of C. trachomatis infection to have another C. trachomatis test in 3 monthsnot as a test of cure but as a test for reinfection (11). We wondered whether men might also benefit from retesting, whether retesting should be expanded to include persons with N. gonorrhoeae or Trichomonas vaginalis infections (12), and whether there were other factors that clinicians could use to recommend retesting. We analyzed data from a large prevention counseling trial (13) that included baseline and 4 scheduled follow-up visits of patients in 3 sexually transmitted disease (STD) clinics to determine the incidence of new sexually transmitted infections during the year after a visit to the clinics. Methods A multicenter randomized, controlled trial of HIV prevention counseling with a rapid HIV test or a standard HIV test (RESPECT-2) was conducted in 3 public STD clinics in Denver, Colorado; Long Beach, California; and Newark, New Jersey. Primary analyses and detailed methods are described elsewhere (13). Briefly, eligible clients were those who came to the clinics for a full diagnostic examination for sexually transmitted infections, were HIV-negative at enrollment, reported having vaginal or anal sex in the preceding 3 months, and were 15 to 39 years of age. At the initial visit, participants were counseled, examined, and tested for sexually transmitted infections and HIV infection. Outcomes were measured at 13-week intervals, scheduled 3, 6, 9, and 12 months from the date of enrollment. Before each follow-up visit, study staff mailed a reminder letter to each participant and made a reminder telephone call. When participants did not keep appointments, staff mailed additional reminder letters and made additional telephone calls to reschedule the visit as needed. Participants who were due for a study follow-up visit were screened for sexually transmitted infections and were interviewed if they visited the clinic any time from 1 week before the due date up to 12 weeks after the due date. Participants were given

Relative Efficacy of Prevention Counseling With Rapid and Standard HIV Testing: A Randomized, Controlled Trial (RESPECT-2)

25 for completing each follow-up visit. This amount was later increased to

Transfusion-associated acquired immunodeficiency syndrome. Evidence for persistent infection in blood donors.

50 in an attempt to improve retention rates. Participants were tested for C. trachomatis, N. gonorrhoeae, and T. vaginalis infections at enrollment, at each quarterly follow-up visit, and at other visits not related to the study that occurred during the 12-month follow-up period (interim visits). An incident sexually transmitted infection was defined as a positive laboratory result either preceded by a negative result for the same infection or detected more than 14 days after provision of antibiotics effective against that infection. Testing was done in the local laboratories used by each clinic. Tests for C. trachomatis and N. gonorrhoeae infections were done on urine specimens by using nucleic acid amplification tests. The sensitivity and specificity values from the package inserts for these tests are cited here; the exact values are difficult to establish because there is no gold standard for identifying infected patients (14). The Long Beach and Newark clinics used ligase chain reaction (LCx Uriprobe, Abbott Diagnostics Division, Abbott Park, Illinois); the sensitivity and specificity for C. trachomatis were 93.1% and 97.1%, respectively, and the sensitivity and specificity for N. gonorrhoeae were 97.5% and 98.3%, respectively (15, 16). The Denver clinic used polymerase chain reaction initially (Cobas Amplicor, Roche Diagnostic Systems, Inc., Branchburg, New Jersey); the sensitivity and specificity for C. trachomatis were 93.4% and 96.7%, respectively, and the sensitivity and specificity for N. gonorrhoeae were 97.1% and 98.1%, respectively (17, 18). Eighteen months later, however, this clinic changed to using strand displacement amplification (BDProbeTec ET, BD Diagnostic Systems, Sparks, Maryland); the sensitivity and specificity for C. trachomatis were 90.7% and 96.6%, respectively, and the sensitivity and specificity for N. gonorrhoeae were 96.0% and 98.8%, respectively) (19). Trichomonas vaginalis was cultured by using the InPouch TV test (BioMed Diagnostics Inc., San Jose, California) or modified Diamond medium as the culture medium. The sensitivity has been estimated at 82.4% for the InPouch TV test and 87.8% for Diamond medium; specificity for both culture methods is nearly 100% (20). Cultures were done by using vaginal swab specimens from women. At follow-up visits, vaginal swabs were collected by the participant (Denver and Long Beach) or by a clinician (Newark), depending on local clinic policy. Behavioral data were collected by using Audio Computer-Assisted Self-Interview technology at enrollment and at each scheduled study follow-up visit. For most questions, a uniform 3-month recall period was used, regardless of the time since the most recent study visit. Because previous work has shown that most new infections are asymptomatic, we limited our analysis to participants who returned for testing and therefore could be classified as infected or not infected. Return visits with testing and interviews were scheduled every 3 months, and most participants returned within 2 weeks of their scheduled time. However, some participants also returned before their scheduled visit because of concern about a possible infection. Those who returned early were tested for sexually transmitted infections and were told to return for their scheduled visit for the interview and repeated testing. All test results from interim visits between 2 interviews were associated with behaviors reported during the next scheduled interview after the interim tests. Study interviews were conducted the first time the participant returned during the scheduled follow-up time (visit 1, 84 to 174 days; visit 2, 175 to 265 days; visit 3, 266 to 356 days; and visit 4, 357 to 448 days). Test data from participants who missed interviews were grouped in the analysis with their next interview. We excluded data from visits that occurred after participants missed 2 consecutive follow-up interviews. Men who reported having sex with men in the baseline interview were also excluded because of the small sample size. Person-years at risk were calculated by using the time between interviews. Participants could contribute up to 4 intervals of observation. Those who had multiple infections with the same organism in the same interval were only counted as having 1 infection, but if an infection recurred in a different interval it was counted again. We looked for 2 types of risk factors for infection. First, we looked for characteristics that clinicians could identify during a clinic visit that might predict infection at a subsequent visit. These factors included demographic characteristics, past risk behaviors, and infections detected during that visit. Second, we looked at events that might occur during follow-up that would alert patients to a need to return for testing for sexually transmitted infections. These factors included acquiring a new partner or having sex with more than 1 partner. Multivariate analysis of factors associated with sexually transmitted infection included serial measures for each participant. We performed unconditional logistic regression using generalized estimating equations, which accounted for within-participant correlations of repeated measures (21). Because this method assumes that missing data are missing completely at random, we assessed the relationship between missing visits and response variables for all 2419 participants included in our stu

Changes in sexually transmitted disease rates after HIV testing and posttest counseling, Miami, 1988 to 1989.

Background: Two risk-reduction counseling sessions can prevent sexually transmitted diseases (STDs); however, return rates for test results are low. Study: A randomized, controlled trial compared rapid HIV testing and counseling in 1 visit with standard HIV testing and counseling in 2 visits. Main outcomes were STDs (gonorrhea, chlamydia, trichomoniasis, syphilis, HIV) within 12 months. Participants were 15- to 39-year-old STD clinic patients in Denver, Long Beach, and Newark. STD screening and questionnaires were administered every 3 months. Results: Counseling was completed by 1632 of 1648 (99.0%) of the rapid-test group and 1144 of 1649 (69.4%) of the standard-test group. By 12 months, STD was acquired by 19.1% of the rapid group and 17.1% of the standard group (relative risk [RR], 1.11; confidence interval [CI], 0.96–1.29). STD incidence was higher in the rapid-test group than in the standard-test group among men (RR, 1.34; CI, 1.06–1.70), men who had sex with men (RR, 1.86; 95% CI, 0.92–3.76), and persons with no STDs at enrollment (RR, 1.21; 95% CI, 0.99–1.48). Behavior was similar in both groups. Conclusions: Counseling with either test had similar effects on STD incidence. For some persons, counseling with standard testing may be more effective than counseling with rapid testing.

The Changing Epidemiology of Syphilis

To investigate whether infection with human T-cell lymphotropic virus/lymphadenopathy-associated virus (HTLV-III/LAV) may be persistent in asymptomatic persons and to correlate infection with seropositivity the authors performed virologic and serologic studies in 25 of 30 persons who were identified as being at high risk for the acquired immunodeficiency syndrome (AIDS) and who had donated blood to patients who later contracted transfusion-associated AIDS. High-risk donors were those who belonged to a high-risk population had AIDS or a closely related condition or had a low ratio of helper to suppressor T lymphocytes. The authors performed similar studies in 6 of the 24 patients with AIDS who had received donations from this group. HTLV-III/LAV was isolated from 22 of the 25 donors between 12 and 52 months (mean 28) after they had donated blood and from all 6 recipients between 14 and 37 months (mean 26) after they had received blood. Of the 22 virus-positive donors 2 have contracted AIDS 5 have generalized lymphadenopathy and 15 (68%) remain asymptomatic. Antibodies to HTLV-III/LAV were detectable by the enzyme-linked immunosorbent assay in serum samples obtained from each person at the time the virus was isolated. It is concluded that infection with HTLV-III/LAV may be persistent and asymptomatic for years. This demonstrates that viremic patients may be asymptomatic supports the use of serologic screening of donated blood to supplement current procedures for the prevention of transfusion-associated AIDS. (authors)

Sexually transmitted disease (STD) and HIV risk in heterosexual adults attending a public STD clinic: Evaluation of a randomized controlled behavioral risk-reduction intervention trial.

OBJECTIVES The effects of posttest counseling on acquisition of sexually transmitted diseases in patients at a large urban sexually transmitted disease clinic were studied. METHODS Comparisons were made of the percentage of patients who had a positive gonorrhea culture (or any sexually transmitted disease) in the 6 months before and after human immunodeficiency virus (HIV) counseling and testing. RESULTS For 331 patients counseled about a positive HIV test, the percentage with gonorrhea was 6.3 before and 4.5 after posttest counseling (29% decrease). For 666 patients counseled about a negative test, the percentage with gonorrhea was 2.4 before and 5.0 after posttest counseling (106% increase). With any sexually transmitted disease as the outcome, patients who tested positive for HIV had a 12% decrease and patients who tested negative had a 103% increase after counseling. CONCLUSIONS HIV counseling and testing was associated with a moderate decrease in sexually transmitted diseases among patients who tested positive for the virus, but risk increased for patients who tested negative. This suggests a need to improve posttest counseling in this clinic and to assess the effects of counseling and testing in other clinics.

Incidence of herpes simplex virus type 2 infection in 5 sexually transmitted disease (STD) clinics and the effect of HIV/STD risk-reduction counseling

AFTER DECLINING EVERY YEAR since 1990, and less than 2 years after the launching of the National Plan to Eliminate Syphilis in the United States, rates of primary and secondary syphilis increased slightly in 2001.1 New epidemics involving men who have sex with men (MSM) have since been detected in most major US cities. If we could identify the persons who are most likely to acquire the next syphilis infections and why, we might be able to reach them early and prevent acquisition or reach them soon after they are infected and treat them before they transmit to others. This requires identifying characteristics of persons acquiring infection, how they are meeting partners, and how they are transmitting infection. When this information is known, we can warn the population at risk so they can take precautions to avoid infection or perhaps recognize an infection when they get it. We can also more effectively target screening campaigns and alert health care workers to look for infections among persons at risk. We also want to know how large the current syphilis epidemic will become because it will help with resource allocation decisions. Interventions early in an epidemic may halt transmission that could otherwise eventually become highly magnified. However, effective interventions can be expensive, even early in an epidemic. It is easier to justify extensive interventions for an epidemic that would otherwise grow to millions of cases (e.g., acquired immunodeficiency syndrome [AIDS]) than it is for an epidemic that would ultimately involve a small number of cases (e.g., hantavirus pulmonary syndrome). Finally, we want to know what this epidemic is telling us about other sexually transmitted infections, particularly human immunodeficiency virus (HIV). There has been concern that advances in antiretroviral therapy were leading to disinhibition of the sexual behaviors that were changed due to the AIDS epidemic.2,3 A relaxation of safe-sex practices could lead to resurgence of HIV and AIDS; however, increases in HIV transmission can be very difficult to identify because of the long and variable incubation period. Thus, other indicators have been used to try to identify effectiveness of HIV prevention programs.4 Some studies have suggested there have been increases in unprotected anal sex.3,5,6 Other studies suggest gonorrhea rates have increased among MSM.6,7 Is the current syphilis epidemic another indication that HIV transmission is increasing? We will address these questions by reviewing surveillance data reported to CDC and published epidemiologic research from the United States and elsewhere.

Sociodemographic factors and the variation in syphilis rates among US counties, 1984 through 1993: an ecological analysis.

Objective:To evaluate the efficacy of a cognitive/behavioral skills-building intervention to prevent sexually transmitted diseases (STD) in high-risk heterosexual adults. Design:A randomized controlled trial with assessments at baseline, and at 3 and 5 months. Setting:San Francisco STD Clinic. Patients:A total of 399 patients were randomly assigned to a four-session, individual, multi-component, cognitive/behavioral intervention (n = 199), or a brief standardized counseling session offered to all patients (n = 200). Intervention:Based on the AIDS Risk-Reduction Model, the aims of the intervention were to increase prevention knowledge, reduce high-risk psychosocial factors, and build decision-making and communication skills to modify sexual behaviors. Main outcome measures:The primary outcome of interest was STD. The secondary outcome was number of risky sexual activities. Results:There were no differences between the intervention (13%) and control (11%) groups in their acquisition of STD. Among men, condom use increased more at 3 months in the intervention group than the control group (56.8 versus 42.3%; P< 0.05). In addition, the mean number of sexual partners without condom use was lower in the intervention group than in the control group at 5 months (0.6 versus 0.9; P< 0.01). Conclusions:The results suggest that a cognitive/behavioral, skills-building intervention consisting of individual, multiple sessions and follow-up assessments can be implemented and evaluated with high-risk heterosexually active adults attending public STD clinics. Our intervention did not have a significant impact on STD, although it had some impact on behavior in men, but not in women.