Incidence of HIV infection among gay men in a London HIV testing clinic, 1997-1998

Temporal trends of transmitted HIV drug resistance in a multinational seroconversion cohort

BACKGROUND

The rate of transmitted drug resistance (TDR) may increase with wider use of antiretroviral therapy and can contribute to therapeutic failure. We analysed time trends in TDR among HIV seroconverters.

METHODS

Using CASCADE data of individuals with well estimated dates of HIV seroconversion, we examined HIV nucleotide sequences collected prior to antiretroviral therapy use from 1996-2012. All samples were taken within 12 months of testing HIV positive. Using logistic regression, we examined the association between TDR and year of seroconversion, adjusting for confounders.

RESULTS

Of 4717 individuals seroconverting between 1996 and 2012, median (IQR) age at seroconversion was 33 (27, 39) years. The majority (3839; 92%) were male, mainly exposed through MSM (3767; 80%), and infected with subtype B (3464; 73%). Overall, 515 (11%) individuals had at least one drug resistance-related mutation; 280 individuals with nucleoside reverse transcriptase, 185 with nonnucleoside reverse transcriptase, and 144 with protease inhibitor mutations. Estimated TDR prevalence was 19.4% (8.2, 36.0) in 1996, significantly decreasing to 8.5% (5.9, 11.9) in 2012 [odds ratio (OR; 95% confidence interval (CI)) = 0.92 (0.90, 0.95) per year increase]. Individuals exposed through sex between men and women were significantly less likely to have been infected with a drug-resistant strain [OR (95% CI) = 0.59 (0.41, 0.87) compared with MSM], and there was marginal evidence that sampling during acute infection was associated with higher odds of resistance [OR (95% CI) = 1.20 (0.97, 1.7), P = 0.093] compared with later sampling.

CONCLUSION

TDR has decreased over calendar time although a significant proportion of new infections still carry resistance-related mutations.

Trends in HIV testing, prevalence among first-time testers, and incidence in most-at-risk populations in Spain: the EPI-VIH Study, 2000 to 2009

During 2000 to 2009, data on people undergoing HIV testing and on those newly diagnosed with HIV were collected in a network of 20 Spanish clinics specialising in sexually transmitted infections and/or HIV testing and counselling. The number of tests performed, overall and disaggregated by different variables, was obtained. HIV prevalence among first-time testers and HIV incidence among repeat testers were calculated. To evaluate trends, joinpoint regression models were fitted. In total, 236,939 HIV tests were performed for 165,745 individuals. Overall HIV prevalence among persons seeking HIV testing was 2.5% (95% CI: 2.4 to 2.6). Prevalence was highest in male sex workers who had sex with other men (19.0% (95% CI: 16.7 to 21.4)) and was lowest in female sex workers (0.8% (95% CI: 0.7 to 0.9)). Significant trends in prevalence were observed in men who have sex with men (MSM) (increasing) and heterosexual individuals (decreasing). The incidence analysis included 30,679 persons, 64,104 person-years (py) of follow-up and 642 seroconversions. The overall incidence rate (IR) was 1.0/100 py (95% CI: 0.9/100 to 1.1/100). Incidence was significantly higher in men and transgender females than in women (1.8/100 py (95% CI: 1.6 to 1.9), 1.2/100 py (95% CI: 0.5 to 2.8) and 0.1/100 py (95% CI: 0.09 to 0.2) respectively) and increased with age until 35–39 years. IRs in MSM and people who inject drugs were significantly greater than in heterosexual individuals (2.5/100 py (95% CI: 2.3 to 2.7), 1.6/100 py (95% CI: 1.1 to 2.2) and 0.1/100 py (95% CI: 0.09 to 0.2) respectively), and an upward trend was observed in MSM. Our results call for HIV prevention to be reinforced in MSM and transgender women in Spain.

CD4 decline in seroconverter and seroprevalent individuals in the precombination of antiretroviral therapy era

BACKGROUND

Studies based on seroconverters have increased our understanding of HIV disease. It is not clear, however, whether their disease progression differs from that of the general HIV population, given their reasons for presenting for testing.

METHODS

Using linear mixed models we compared CD4 decline rates for a seroconverter (CASCADE) and seroprevalent group (Concorde trial) with time origin being dates of seroconversion and randomization, respectively. Follow-up was censored at the earlier of last alive date and 1 January 1996. Analyses were adjusted for risk group, age and sex. To explore the role of symptomatic seroconversion we further categorized seroconverters into two groups: with and without an HIV test interval below 30 days as proxy.

RESULTS

The 7226 seroconverter and 1746 seroprevalent eligible individuals were mainly men (78 and 85%, respectively) infected through sex between men (52 and 63%) with mean [95% confidence interval (CI)] baseline CD4 cell count of 610 (602, 619) and 492 (479, 505) cells/μl, respectively. There was no evidence that rate of CD4 decline differs between the two groups even after adjusting for potential confounders (P = 0.67). Estimated loss in the year after reaching an arbitrary threshold of 400 cells/μl was 67 (95% CI 65, 69) and 67 (64, 69) cells/μl in the seroconverter and seroprevalent group, respectively. Whereas seroconverters with test interval below 30 days (n = 310) experienced faster decline, there was no difference in rates between other seroconverters and seroprevalent individuals (P = 0.87).

CONCLUSIONS

These data suggest that estimates of HIV progression derived from seroconverters are likely to hold more generally for the HIV-infected population.

Outcomes and lessons from a pilot RCT of a community-based HIV prevention multi-session group intervention for gay men

This paper presents the first outcome evaluation of multi-session groupwork for HIV prevention among gay men in the UK. This community-based RCT recruited 50 men, of whom 42% were HIV-positive or untested, and 32% reported status unknown or serodiscordant UAI in the previous 12 months. No knowledge, skills, attitudinal or behavioural differences were detected between intervention and control at baseline. At eight weeks, those attending the group reported significant gains over their control in making sexual choices, physical safety, HIV and STI transmission knowledge, and sexual negotiation skills. At 20 weeks, significant differences remained for HIV and STI transmission knowledge and comfort with sexual choices. Although no behavioural differences were detected, the aims of the National Prevention Strategy were met. This pilot RCT is appraised in the light of modest sample size and attrition, and recommendations for establishing behavioural outcomes are presented. This study has demonstrated that high-risk community samples can be recruited to multi-session interventions, and has provided feasibility data for future rigorous evaluation designs.

Running in place: implications of HIV incidence estimates among urban men who have sex with men in the United States and other industrialized countries

Attempts to document changing HIV incidence rates among MSM are compromised by issues of generalizability and statistical power. To address these issues, this paper reports annualized mean HIV incidence rates from the entire published incidence literature on MSM from Europe, North America and Australia for the period 1995-2005. Publications that met the entry criteria were coded for region of the world, sampling method and year of study. From these reports, we calculated a mean incidence rate with confidence intervals for these variables. Although no differences in mean incidence rates were found for MSM from 1995 to 2005, HIV incidence rates are lower in Australia than either North America or Europe. We calculated a mean incidence rate of 2.39% for MSM in the United States, which if sustained within a cohort of MSM, would yield HIV prevalence rate of approximately 40% at age 40. These extrapolations overlap published HIV prevalence rates for MSM younger than age 40 in the United States. HIV incidence rates in the 2-3% range will adversely affect the health of gay male communities for decades to come. This analysis suggests that greater attention should be devoted to the question of how best to design prevention interventions that will lower HIV incidence rates among gay men.

Prevalence of HIV infection and predictors of high-transmission sexual risk behaviors among men who have sex with men

OBJECTIVES

We sought to determine the prevalence of HIV and novel cofactors of high-transmission-risk behavior in a probability sample of men who have sex with men (MSM).

METHODS

We performed a cross-sectional telephone survey of 1976 adult MSM in San Francisco.

RESULTS

We found an HIV prevalence of 25.2%. Predictors of unprotected insertive anal intercourse with a serodiscordant (not having the same HIV/AIDS serostatus) partner among HIV-infected men included use of Viagra and a greater number of partners in the past 12 months. Unprotected receptive anal intercourse with a serodiscordant partner among men not known to be HIV infected was independently associated with having lived in San Francisco for less than 1 year, use of crystal methamphetamine and amyl nitrites, a greater number of partners, and agreement with the statement, "You are less careful about being safe with sex or drugs than you were several years ago because there are better treatments for HIV now."

CONCLUSIONS

Strategies to prevent HIV for urban MSM should focus on new predictors of HIV transmission.

Comparison of three methods to measure HIV incidence among persons seeking voluntary, anonymous counseling and testing

OBJECTIVES

The authors compared 3 practical methods to estimate human HIV incidence rates using existing data from persons seeking anonymous testing in San Francisco between 1996-2002. Each method was assessed for strengths and limitations.

METHODS

Three different approaches were used to determine HIV incidence: one based on self-reported dates of prior tests, one based on linking records of prior tests using an anonymous unique testing code, and one based on the Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS).

RESULTS

The 3 methods found comparable rates of seroconversion overall (1.0, 1.2, and 1.3 per 100 person-years) and among men who have sex with men (1.4, 1.6, and 2.0 per 100 person-years). Incidence for all 3 methods saw a peak during 1999 followed by a decline. Greatest variability of incidence was observed among lower-risk populations, in whom few infections were expected.

CONCLUSIONS

The 3 methods had complementary strengths and limitations, which may prevent proper interpretation of HIV incidence if any one method is analyzed alone. HIV incidence rates among persons seeking HIV testing should be interpreted cautiously using corroborative data on risk behavior and sexually transmitted diseases and other contextual information.

Studies relying on passive retrospective cohorts developed from health services data provide biased estimates of incidence of sexually transmitted infections

OBJECTIVE

Passive retrospective cohorts composed of persons who have tested 2 or more times for a sexually transmitted infection (STI) of interest during clinical visits have been used to estimate STI incidence. We hypothesized that the analytic period of a passive cohort might affect the estimate of STI incidence, with shorter periods yielding higher estimates of incidences of infection.

STUDY

We analyzed data collected from women, 12 to 24 years of age, tested for chlamydia 2 or more times at 6 sites in San Francisco between January 1997 and December 2000. Incidence was calculated for 10 different analytic periods.

RESULTS

The calculated incidence of chlamydial infection during 1997 was 16.8 (95% confidence interval [CI], 10.9-24.0) per 1000 person-months of follow up. The calculated incidence dropped markedly as the analytic period lengthened, with the incidence estimated to be 9.7 (95% CI, 8.6-10.9) using a study period of 4 years (1997-2000). Estimates of incidence were similar when using the same analytic period, regardless of calendar year, and there was a similar decline in estimated incidence using longer analytic periods.

CONCLUSIONS

Estimates of STI incidence based on passive cohort data may have limited epidemiologic value because incidence measures may be highly dependent on the analytic period.

Estimation of HIV incidence among repeat anonymous testers in Catalonia, Spain

A retrospective cohort study of 2124 repeat HIV testers attending at anonymous testing sites (ATS) of Catalonia between 1995 and 2001 registered 3273 person-years (PY) of follow-up and 76 seroconversions (incidence density of 2.32 per 100 PY; 95% CI: 1.83, 2.90). The highest HIV infection incidence was observed among heterosexual injection drug users (IDU) (9.25 per 100 PY; 95% CI: 6.77, 12.25) and the lowest was among heterosexual non-IDU (0.69 per 100 PY; 95% CI: 0.35, 1.24). In multivariate Cox regression, factors independently associated with seroconversion were men having sex with men, IDU, and having sex with a known HIV-infected person. In spite of some limitations, such results suggest that prevention interventions targeting specific groups attending at ATS in Catalonia should be prioritized.

Risk behaviors and HIV incidence among repeat testers at publicly funded HIV testing sites in San Francisco

OBJECTIVE

More than 25% of HIV tests are for individuals who have previously been tested. To characterize repeat testers, we 1) estimated the seroincidence of HIV infection, stratified by risk behavior, and examined the association between 2) testing rates and risk level and 3) repeat testing and tester characteristics.

METHODS

Records from HIV counseling and testing (C&T) sites were reviewed. Seroincidence was estimated by linking results of current test with date of last reported HIV negative test. A risk hierarchy of behaviors was created. Repeat testing rates were calculated for each risk level strata. Multivariate models explored the association of repeat testing with tester characteristics.

RESULTS

The HIV seroincidence among repeaters was 1.3 per 100 person-years (range 0.7-7.0 per 100 person-years). The high-risk level subject had a repeater rate of 92%, with 5.3 tests/person and was more likely (odds ratio = 4.96, 95% confidence interval 3.8-6.5) to have tested two or more times, compared with those in the low risk group.

CONCLUSION

The highest users of repeat testing are those who are practicing the highest risk behaviors and have the highest incidence of HIV. This suggests that prevention messages should be modified to more explicitly address the behaviors that are putting individuals at high risk for HIV.

Changing sexual behavior among gay male repeat testers for HIV: a randomized, controlled trial of a single-session intervention

CONTEXT

High-risk sexual behavior is increasingly prevalent among men who have sex with men (MSM) and among men with a history of repeat testing for HIV.

OBJECTIVES

The study assessed whether one counseling intervention session focusing on self-justifications (thoughts, attitudes, or beliefs that allow the participant to engage in high-risk sexual behaviors) at most recent unprotected anal intercourse (UAI) is effective in reducing future high-risk behaviors among HIV-negative men.

DESIGN, SETTING, AND PARTICIPANTS

A randomized, controlled, counseling intervention trial was conducted at an anonymous testing site in San Francisco, California, between May 1997 and January 2000. Participants were 248 MSM with a history of at least one previous negative HIV test result and self-reported UAI (receptive or insertive) in the previous 12 months with partners of unknown or discordant HIV status. Two intervention groups received standard HIV test counseling plus a cognitive-behavioral intervention, and two control groups received only standard HIV test counseling. Follow-up evaluation was at 6 and 12 months.

MAIN OUTCOME MEASURE

Number of episodes of UAI with nonprimary partners (of unknown or discordant HIV status) in the 90 days preceding the interview was measured via self-report during face-to-face interview.

RESULTS

A novel counseling intervention focusing on self-justifications significantly decreased the proportion of participants reporting UAI with nonprimary partners of unknown or discordant HIV status at 6 and 12 months (from 66% to 21% at 6 months and to 26% at 12 months, p =.002; p <.001) as compared with a control group when added to standard client-centered HIV counseling and testing.

CONCLUSIONS

A specific, single-session counseling intervention focusing on a reevaluation of a person's self-justifications operant during a recent occasion of high-risk behavior may prove useful in decreasing individual risk behavior and thus limiting community-level HIV transmission.