HIV Infection Modifies the Role of Prior Treponema pallidum Infection in the Clinical Presentation of Early Syphilis Among Adult Patients From Sexually Transmitted Infection Clinics in Peru

BACKGROUND

We aimed to compare the clinical presentations (symptomatic vs. asymptomatic) with prior Treponema pallidum infection status (first infection vs. reinfection) among people with early syphilis.

METHODS

We used data from PICASSO, a cohort study in Peru that enrolled people with active syphilis from May 2019 to August 2021. Study participants had early syphilis and a prior syphilis serological test result within the prior 12 months to determine prior T. pallidum infection status. We calculated prevalence ratios (PRs) of symptomatic clinical presentation (primary or secondary syphilis) by prior T. pallidum infection status, stratified by HIV infection status. In addition, we explored the association of prior T. pallidum infection status and lesion presentation, stratified by primary and secondary syphilis cases, using the Fisher exact test.

RESULTS

We include 84 T. pallidum reinfection cases and 61 first infection cases. We found increased frequency of symptomatic clinical presentation among first-infection cases (39% vs. 20%; PR, 1.94; P = 0.014). This association was stronger among persons living without HIV infection (38% vs. 7%; adjusted PR, 6.63; P = 0.001) in comparison to those living with HIV infection (45% vs. 34%; adjusted PR, 1.38; P = 0.458). Among secondary syphilis cases, more participants from the reinfection group reported that their lesions improved 1 week after treatment (100% vs. 29%, P = 0.045) compared with those with a first infection. Among the primary syphilis cases, all participants reported that their lesions improved 1 week after treatment.

CONCLUSIONS

Prior syphilis was associated with a decreased prevalence of symptomatic reinfection, especially among persons not living with HIV infection.

Awareness of U = U among Sexual and Gender Minorities in Brazil, Mexico, and Peru: Differences According to Self-reported HIV Status

The slogan Undetectable equals Untransmittable (U = U) communicates that people living with HIV (PLHIV) who are on antiretroviral therapy (ART) will not transmit HIV to their sexual partners. We describe awareness of U = U among sexual and gender minorities (SGM) living in Brazil, Mexico, and Peru by self-reported HIV status (PLHIV, negative, unknown) during 2021 using an online survey. We estimated two models using Poisson regression for each population group: Model A including socio-demographic factors (country, gender, age, race, education, and income), and then Model B including taking ART (for PLHIV) or risk behavior, ever-taking PrEP, and HIV risk perception (for HIV-negative or of unknown HIV status). A total of 21,590 respondents were included (Brazil: 61%, Mexico: 30%, Peru: 9%). Among HIV-negative (74%) and unknown status (12%), 13% ever used PrEP. Among PLHIV (13%), 93% reported current use of ART. Awareness of U = U was 89% in both Brazil and Mexico, which was higher than in Peru 64%. Awareness of U = U was higher among PLHIV (96%) than HIV-negative (88%) and HIV-unknown (70%). In multivariate models, PLHIV with lower education were less aware of U = U, while those taking ART were more aware. Among HIV-negative, non-cisgender, lower income, and those with lower education had lower awareness of U = U, while individuals ever using PrEP had higher awareness. In conclusion, awareness of U = U varied by HIV status, socio-demographic characteristics, and HIV risk behavior. The concept of U = U should be disseminated through educational strategies and include a focus on SGM to combat HIV stigma.

Does genital herpes symptom history predict herpes simplex virus type 2 antibody positivity?

BACKGROUND

Sexually transmitted infections (STIs) associated with genital ulcer disease due to herpes simplex virus-2 (HSV-2) are a prominent cause of morbidity and mortality. Serologic screening for HSV-2 is recommended only for individuals with genital herpes symptom history. However, no validated symptom screening tool currently exists.

METHODS

Currently asymptomatic adults presenting for routine care at STI clinics in Lima, Peru completed a survey of prior genital herpes symptoms and received HSV-2 serological testing with the Euroimmun Anti-HSV-2 (gG2) ELISA IgG (Lubeck, Germany). A sub-sample of indeterminate results were sent for Western blot confirmatory testing. We assessed associations between past symptoms and anti-HSV-2 positivity and corrected the HSV-2 prevalence by re-classifying indeterminates per Western Blot results.

RESULTS

We enrolled 131 participants between July and October 2022. HSV-2 antibody test results found 21.4% positive, 41.2% indeterminate, and 37.4% negative. Excluding indeterminate results, 36.4% were positive. Of participants with no prior symptoms 31.2% tested positive, compared to 35.7% with one prior symptom, 50.0% with 2, and 50.0% with 3+ prior symptoms. Among the sub-sample of indeterminates, 92.6% were confirmed positive by Western Blot, bringing the total estimated proportion of participants with HSV-2 antibodies to 59.5%. Either based on the original classification of HSV-2 antibody status or after incorporation of confirmatory testing results, there was no significant association between symptom history and HSV-2 antibody positivity.

CONCLUSIONS

With currently available tests, recommendations to screen individuals based on genital herpes symptom history may not be useful. More discriminatory symptom screening tools or HSV-2 antibody tests with better performance are needed.

Evaluation of a minimal array of Treponema pallidum antigens as biomarkers for syphilis diagnosis, infection staging, and response to treatment

IMPORTANCE

This manuscript explores the host humoral response to selected antigens of the syphilis agent during infection to evaluate their potential use as diagnostic tests and markers for treatment.

Molecular Characterization of Genital and Extragenital Lesions With the PlexPCR VHS Assay in Patients Diagnosed With Syphilis

Background

Syphilis diagnosis relies on immunologic markers and clinical protocols. However, syphilitic lesions can be confused with other genital ulcer diseases.

Methods

Using a PlexPCR VHS assay, we analyzed lesion DNA samples from 87 individuals who were clinically diagnosed with early syphilis infection and had at least 1 positive serologic test result. DNA was detected by the PlexPCR VHS multiplex assay and β-globin genes.

Results

Among the participants, 99% (86/87) had a positive rapid treponemal test result. DNA was successfully detected in 91% (79/87) of the lesion samples. PlexPCR VHS identified 5 herpes simplex virus (HSV)/Treponema pallidum coinfections (2 HSV-1 and 3 HSV-2), only T pallidum DNA in 62% (49/79), and only HSV-2 in 12.7% (10/79). While 19% (15/79) were negative for all pathogens, none were varicella zoster virus positive. The PlexPCR VHS had 68.4% agreement with the clinical diagnosis.

Conclusions

Since the PlexPCR VHS detects multiple organisms simultaneously, it can help to confirm actual syphilis and identify other pathogen coinfections or the pathogen causing the ulcer.

Contributing factors for self-reported HIV in male Peruvian inmates: results of the 2016 prison census

Introduction

Worldwide, prisons are high-risk settings for the transmission of infectious diseases such as HIV. There is a need to understand the health conditions of prisoners to improve and implement timely strategies for HIV diagnosis and control. Hence, we aimed to identify factors associated with self-reported HIV (srHIV) among Peruvian inmates.

Methods

This study is a secondary data analysis of the First Peruvian Prison Census conducted in 2016. We estimated the prevalence of srHIV in prisoners who were male at birth and the association of srHIV with other social conditions, criminal records, and prevalent health conditions. Nested models identified a multivariable parsimonious model for factors associated with srHIV and yielding prevalence ratios adjusted by the included parameters.

Results

The census surveyed 71,087 male inmates of whom 0.4% reported srHIV (n = 305), and 82% of whom were receiving antiretroviral treatment (n = 220). In our final multivariable model, srHIV was independently associated with age between 36 and 55 years old vs. >55 years old [parsimonious prevalence ratio (pPR) = 1.98, 95% CI, 0.96-4.08], having a stable partner out of prison (pPR = 1.64, 95% CI, 1.24-2.19), being homosexual (pPR = 4.16, 95% CI, 2.50-6.90), self-report of prevalent tuberculosis co-infection (pPR = 2.55, 95% CI, 1.82-3.58), self-report of prevalent sexually transmitted infections (pPR = 34.49, 95% CI, 24.94-47.70), and self-report of prevalent illicit drug use 30 days before the survey (pPR = 1.91, 95% CI, 1.43-2.56).

Conclusion

Self-reported HIV is associated with multiple social, health and prison risks among Peruvian inmates. Deeply understanding these factors would help to design HIV prevention and control strategies in Peruvian prisons.

Extra-genital Neisseria gonorrhoeae infections with genetic mutations conferring ciprofloxacin resistance among men who have sex with men and transgender women in Lima, Peru

BACKGROUND

The increasing prevalence of drug-resistant Neisseria gonorrhoeae (NG) infections has caused great concern. Ciprofloxacin remains the empiric antimicrobial recommended to treat NG infections in Peru disregarding the susceptibility profile of circulating NG strains. We report the prevalence of individuals infected with NG strains presenting mutations in the gyrA gene that confers ciprofloxacin resistance.

METHODS

We conducted a descriptive study assessing extragenital swab samples collected from a cohort of men who have sex with men and transgender women in Lima, Peru. Anal and pharyngeal NG positive swabs for Aptima Combo 2 assay (Hologic Inc., USA) were used for DNA extraction. We performed TaqMan real time PCR assays to detect a point mutation at codon Ser91 of the gyrase A (gyrA) gene.

RESULTS

From 156 individuals who had at least one positive sample for NG reported by the Aptima assay, 80 individuals had at least one amplified DNA for the gyrA gene. We found that 67 of them (84.0%) were infected with a gyrA-mutated NG strain at the Ser91 codon.

CONCLUSIONS

We report a high prevalence of gyrA mutation conferring ciprofloxacin resistance among individuals with extragenital NG infection. Empirical treatment of NG needs to be urgently updated in Peru in concordance with international guidelines.

Preferences for PrEP modalities among gay, bisexual, and other men who have sex with men from Brazil, Mexico, and Peru: a cross-sectional study

Background

Pre-exposure prophylaxis (PrEP) scale-up is urgent to reduce new HIV cases among gay, bisexual, and other men who have sex with men (MSM) in Latin America. Different PrEP modalities may increase PrEP uptake and adherence, especially among young MSM.

Objectives

To assess preferences for PrEP modalities among MSM from Brazil, Mexico, and Peru.

Design

Cross-sectional web-based study (March-May 2018) targeting MSM through advertisements on Grindr, Hornet, and Facebook. We included MSM aged ⩾ 18 years and who reported HIV-negative status.

Methods

We assessed preferences for PrEP modalities with the following question: 'Considering that all following PrEP modalities were available, which one would you prefer considering a scale from 1 to 3 (1 = most preferred): daily oral PrEP, event-driven PrEP (ED-PrEP), and long-acting injectable PrEP'. We assessed factors associated with each most preferred PrEP modality per country using multivariable logistic regression models.

Results

A total of 19,457 MSM completed the questionnaire (Brazil: 58%; Mexico: 31%; Peru: 11%); median age was 28 years [interquartile range (IQR): 24-34]. Overall, injectable PrEP was the most preferred modality [42%; 95% confidence interval (CI): 41-43], followed by daily PrEP (35%; 95% CI: 34-35), and ED-PrEP (23%; 95% CI: 23-24). In multivariable models, preferring injectable PrEP was associated with PrEP awareness in all three countries, while PrEP eligibility only in Brazil. Preferring daily PrEP was associated with younger age and lower income in Brazil and Mexico, and lower education only in Brazil. The odds of preferring ED-PrEP were lower among MSM aware and eligible for PrEP in Brazil and Mexico.

Conclusions

Long-acting injectable PrEP was the preferred PrEP modality among MSM in Brazil, Mexico, and Peru, especially those aware and eligible for PrEP. Public health interventions to increase PrEP modalities literacy and availability in Latin America are urgent especially among MSM of young age, lower income, and lower education.

Same-day initiation of oral pre-exposure prophylaxis among gay, bisexual, and other cisgender men who have sex with men and transgender women in Brazil, Mexico, and Peru (ImPrEP): a prospective, single-arm, open-label, multicentre implementation study

BACKGROUND

Although gay, bisexual, and other cisgender men who have sex with men (MSM) and transgender women have the highest HIV burden in Latin America, pre-exposure prophylaxis (PrEP) implementation is poor. We aimed to assess the feasibility of same-day oral PrEP delivery in Brazil, Mexico, and Peru.

METHODS

Implementation PrEP (ImPrEP) was a prospective, single-arm, open-label, multicentre PrEP implementation study conducted in Brazil (14 sites), Mexico (four sites), and Peru (ten sites). MSM and transgender women were eligible to participate if they were aged 18 years or older, HIV-negative, and reported one or more prespecified criteria. Enrolled participants received same-day initiation of daily oral PrEP (tenofovir disoproxil fumarate [300 mg] coformulated with emtricitabine [200 mg]). Follow-up visits were scheduled at week 4 and quarterly thereafter. We used logistic regression models to identify factors associated with early loss to follow-up (not returning after enrolment), PrEP adherence (medication possession ratio ≥0·6), and long-term PrEP engagement (attending three or more visits within 52 weeks). This study is registered at the Brazilian Registry of Clinical Trials, U1111-1217-6021.

FINDINGS

From Feb 6, 2018, to June 30, 2021, 9979 participants were screened and 9509 were enrolled (Brazil n=3928, Mexico n=3288, and Peru n=2293). 543 (5·7%) participants were transgender women, 8966 (94·3%) were cisgender men, and 2481 (26·1%) were aged 18-24 years. There were 12 185·25 person-years of follow-up. 795 (8·4%) of 9509 participants had early loss to follow-up, 6477 (68·1%) of 9509 were adherent to PrEP, and 5783 (70·3%) of 8225 had long-term PrEP engagement. Transgender women (adjusted odds ratio 1·60, 95% CI 1·20-2·14), participants aged 18-24 years (1·80, 1·49-2·18), and participants with primary education (2·18, 1·29-3·68) had increased odds of early loss to follow-up. Transgender women (0·56, 0·46-0·70), participants aged 18-24 years (0·52, 0·46-0·58), and those with primary education (0·60, 0·40-0·91) had lower odds of PrEP adherence. Transgender women (0·56, 0·45-0·71), participants aged 18-24 years (0·56, 0·49-0·64), and those with secondary education (0·74, 0·68-0·86) had lower odds of long-term PrEP engagement. HIV incidence was 0·85 per 100 person-years (95% CI 0·70-1·03) and was higher for transgender women, participants from Peru, those aged 18-24 years, Black and mixed-race participants, and participants who were non-adherent to PrEP.

INTERPRETATION

Same-day oral PrEP is feasible for MSM and transgender women in Latin America. Social and structural determinants of HIV vulnerability need to be addressed to fully achieve the benefits of PrEP.

FUNDING

Unitaid, WHO, and Ministries of Health in Brazil, Mexico, and Peru.

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Factors associated with long-term HIV pre-exposure prophylaxis engagement and adherence among transgender women in Brazil, Mexico and Peru: results from the ImPrEP study

Introduction

The HIV epidemic continues to disproportionately impact Latin‐American transgender women (TGW). We assessed factors associated with long‐term pre‐exposure prophylaxis (PrEP) engagement and adherence among TGW enrolled in the Implementation of PrEP (ImPrEP) study, the largest PrEP demonstration study in Latin America.

Methods

HIV‐negative TGW aged ≥18 years reporting 1+eligibility criteria in the 6 months prior to enrolment (e.g. sex partner known to be living with HIV, condomless anal sex [CAS], transactional sex or having a sexually transmitted infection [STI]) who could safely take PrEP were enrolled. Follow‐up visits were conducted at 4 weeks and then quarterly. We conducted logistic regression to identify factors associated with long‐term PrEP engagement (3+ follow‐up visits in 52 weeks) and complete self‐reported adherence (no missed pills in the past 30 days) during follow‐up. For both outcomes, we constructed multivariable models controlling for country, socio‐demographics, sexual behaviour, substance use, STIs and self‐reported adherence at 4 weeks (long‐term engagement outcome only).

Results

From March 2018 to June 2021, ImPrEP screened 519 TGW, enrolled 494 (Brazil: 190, Mexico: 66 and Peru: 238) and followed them for 52 weeks. At baseline, 27.5% of TGW were aged 18–24 years, 67.8% were mixed‐race and 31.6% had >secondary education. Most, 89.9% reported CAS, 61.9% had >10 sex partners and 71.9% reported transactional sex. HIV incidence was 1.82 cases per 100 person‐years (95% confidence interval [CI]: 0.76–4.38). Almost half of TGW (48.6%) had long‐term PrEP engagement, which was positively associated with reporting complete adherence at week 4 (aOR:2.94 [95%CI:1.88–4.63]) and was inversely associated with reporting CAS with unknown‐HIV partner (aOR:0.52 [95%CI:0.34–0.81]), migration (aOR:0.54 [95%CI:0.34–0.84]), and being from Mexico (aOR:0.28 [95%CI:0.14–0.53]). Self‐reported adherence was associated with TGW aged >34 (aOR:1.61 [95%CI:1.10–2.34]) compared to those aged 25–34 and those with >secondary education (aOR:1.55 [95%CI:1.10–2.19]) and was lower among TGW from Peru (aOR:0.29 [95%CI:0.21–0.41]) or reporting PrEP‐related adverse effects (aOR:0.63 [95%CI:0.42–0.92]).

Conclusions

Although TGW were willing to enrol in ImPrEP, long‐term PrEP engagement and complete self‐reported adherence were limited, and HIV incidence remained relatively high. A successful HIV prevention agenda should include trans‐specific interventions supporting oral PrEP and exploring long‐acting PrEP strategies for TGW.

High-throughput nanopore sequencing of Treponema pallidum tandem repeat genes arp and tp0470 reveals clade-specific patterns and recapitulates global whole genome phylogeny

Sequencing of most Treponema pallidum genomes excludes repeat regions in tp0470 and the tp0433 gene, encoding the acidic repeat protein (arp). As a first step to understanding the evolution and function of these genes and the proteins they encode, we developed a protocol to nanopore sequence tp0470 and arp genes from 212 clinical samples collected from ten countries on six continents. Both tp0470 and arp repeat structures recapitulate the whole genome phylogeny, with subclade-specific patterns emerging. The number of tp0470 repeats is on average appears to be higher in Nichols-like clade strains than in SS14-like clade strains. Consistent with previous studies, we found that 14-repeat arp sequences predominate across both major clades, but the combination and order of repeat type varies among subclades, with many arp sequence variants limited to a single subclade. Although strains that were closely related by whole genome sequencing frequently had the same arp repeat length, this was not always the case. Structural modeling of TP0470 suggested that the eight residue repeats form an extended α-helix, predicted to be periplasmic. Modeling of the ARP revealed a C-terminal sporulation-related repeat (SPOR) domain, predicted to bind denuded peptidoglycan, with repeat regions possibly incorporated into a highly charged β-sheet. Outside of the repeats, all TP0470 and ARP amino acid sequences were identical. Together, our data, along with functional considerations, suggests that both TP0470 and ARP proteins may be involved in T. pallidum cell envelope remodeling and homeostasis, with their highly plastic repeat regions playing as-yet-undetermined roles.

Notes on syphilis vaccine development

The quest for a syphilis vaccine to provide protection from infection or disease began not long after the isolation of the first Treponema pallidum subspecies pallidum (T. pallidum) strain in 1912. Yet, a practical and effective vaccine formulation continues to elude scientists. Over the last few years, however, efforts toward developing a syphilis vaccine have increased thanks to an improved understanding of the repertoire of T. pallidum outer membrane proteins (OMPs), which are the most likely syphilis vaccine candidates. More has been also learned about the molecular mechanisms behind pathogen persistence and immune evasion. Published vaccine formulations based on a subset of the pathogen's OMPs have conferred only partial protection upon challenge of immunized laboratory animals, primarily rabbits. Nonetheless, those experiments have improved our approach to the choice of immunization regimens, adjuvants, and vaccine target selection, although significant knowledge gaps remain. Herein, we provide a brief overview on current technologies and approaches employed in syphilis vaccinology, and possible future directions to develop a vaccine that could be pivotal to future syphilis control and elimination initiatives.

Laboratory Evaluation of the DPP Syphilis Screen & Confirm Assay

Because syphilis is a public health concern, new strategies and tools for detecting active syphilis cases should be evaluated for future implementation. We assessed the laboratory performance of the DPP Syphilis Screen & Confirm rapid immunodiagnostic test (Chembio Diagnostics, Medford, NY, USA), using visual reading and the manufacturer's electronic test microreader, for detection of treponemal and nontreponemal antibodies in 383 fully characterized stored serum specimens. We used the Treponema pallidum particle agglutination (TPPA) test and rapid plasma reagin (RPR) test as reference tests for the DPP Syphilis Screen & Confirm assay treponemal and nontreponemal components, respectively. The sensitivity values for treponemal antibody detection by electronic reader and visual interpretation were 83.2% and 85.9%, respectively, with 100% specificity. For nontreponemal antibody detection, the sensitivity values were 65.7% and 69.0% and the specificity values were 88.7% and 89.4% for electronic reader and visual interpretation, respectively. There was excellent correlation between visual interpretation and the microreader for either component (kappa coefficient, 0.953). When restricting the analysis to RPR titers of ≥1:8, the sensitivity was 96.9% for either reading method; numerical microreader values showed good correlation with RPR titers (Spearman rho of 0.77). The DPP Syphilis Screen & Confirm assay showed good performance, compared to reference syphilis tests, using serum. Field evaluation studies should be done to validate its use for detection of active cases and for monitoring of treated syphilis patients. IMPORTANCE Syphilis remains a public health problem; therefore, health systems must incorporate screening tools that allow a rapid and accurate diagnosis to provide adequate treatment. The DPP Syphilis Screen & Confirm Assay simultaneously detects treponemal and nontreponemal antibodies, emerging as an alternative for identifying cases in situations in which there is no infrastructure to perform conventional syphilis testing, but it is necessary to generate evidence regarding the performance of this technology in various scenarios. We found that the test performs well, compared to TPPA and RPR tests, using stored samples from participants at high risk of acquiring syphilis. Additionally, when the Chembio microreader was incorporated, similar results are obtained by the device, compared to those reported by trained laboratory professionals, and correlated with the semiquantitative results of the RPR test. We think that the use of the DPP Syphilis Screen & Confirm Assay with the microreader might help in detecting active syphilis cases and perhaps in monitoring treatment responses in the field.

Awareness, knowledge, and attitudes related to HIV pre-exposure prophylaxis and other prevention strategies among physicians from Brazil and Mexico: cross-sectional web-based survey

Background

In order to end the HIV epidemic by 2030, combination HIV prevention including pre-exposure prophylaxis (PrEP) should be widely available, especially for the most vulnerable populations. In Latin America and the Caribbean (LAC), only 14 out of 46 countries have access to PrEP. In Brazil and Mexico, PrEP has been provided at no cost through the Public Health System since 2017 and 2021, respectively. Thus, HIV physicians’ perspectives about PrEP and other prevention strategies may differ. This study aimed to compare awareness, knowledge, and attitudes related to PrEP and other prevention strategies among HIV physicians from Brazil and Mexico.

Methods

Cross-sectional, web-based survey targeting physicians who prescribe antiretrovirals from both countries. Participants answered questions on socio-demographic, medical experience, awareness, knowledge, and attitudes towards PrEP and other HIV prevention strategies. We stratified all variables per country and compared frequencies using Chi-square, Fisher exact, and Wilcoxon-Mann-Whitney tests, as appropriate.

Results

From January–October 2020, 481 HIV physicians were included: 339(70.5%) from Brazil, 276(57.4%) male, and median age was 43 years (IQR = 36–53). Awareness of PrEP did not differ between Brazil and Mexico (84.6%), while awareness of other prevention strategies, including post-exposure prophylaxis and new PrEP technologies, was higher in Brazil. More Brazilians perceived U=U as completely accurate compared to Mexicans (74.0% vs. 62.0%, P < .001). Willingness to prescribe PrEP was 74.2%, higher among Brazilians (78.2%, P = .01). Overall, participants had concerns about consistent access to PrEP medication and the risk of antiretroviral resistance in case of acute HIV infection or seroconversion. The main barriers reported were assumptions that users could have low PrEP knowledge (62.0%) or limited capacity for adherence (59.0%). Compared to Brazilians, Mexicans reported more concerns and barriers to PrEP prescription (all; P ≤ .05), except for consistent access to PrEP medication and the lack of professionals to prescribe PrEP (both; P ≤ .01).

Conclusions

Although awareness of PrEP was similar in Brazil and Mexico, differences in knowledge and attitudes may reflect the availability and stage of PrEP implementation in these countries. Strengthening and increasing information on PrEP technologies and other HIV prevention strategies among HIV physicians could improve their comfort to prescribe these strategies and facilitate their scale-up in LAC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-07900-y.

Awareness, willingness and barriers to HIV Self-testing (HIVST) among Men who Have Sex with Men (MSM) in Brazil, Mexico, and Peru: A web-based cross-sectional study

HIV self-testing (HIVST) is an essential tool within the combined HIV prevention package and has been available in Latin America since 2015. However, HIVST use among key populations remains low. This study describes awareness, willingness, and barriers to HIVST among MSM in Brazil, Mexico, and Peru. A cross-sectional web-based survey was advertised in two geosocial networking apps (Grindr and Hornet) and Facebook in 2018. We included cisgender men ≥18 years old who self-reported HIV-negative status. We used multivariable Poisson regression models to calculate adjusted prevalence ratios (aPR) to assess the factors associated with willingness to use HIVST for each country. A total of 18,916 completed the survey, 59% from Brazil, 30% from Mexico, and 11% from Peru. Overall, 20% of MSM had never tested for HIV. Awareness and willingness to use HIVST were higher in Brazil than in Peru and Mexico (p < .001). Across the countries, the patterns of association of willingness with HIVST barriers were similar. Most participants think post-test counseling is essential and that dealing with a positive result would be difficult (aPR 1.13 to 1.37, range of aPRs across the three countries). Having the knowledge to deal with a positive HIVST resulted in increased willingness to use HIVST (aPR range: 1.11 to 1.22), while a lack of trust in HIVST compared to HIV testing in clinics was inversely associated (aPR range: 0.80 to 0.90). In general, willingness to use HIVST was associated with higher income (aPR range: 1.49 to 1.97), higher education (aPR range: 1.13 to 1.42), and willingness to use PrEP (aPR range: 1.19 to 1.72). Efforts to increase HIVST knowledge and resolve perceived barriers are warranted, especially among MSM with lower income and education from Brazil, Mexico, and Peru. Personalized virtual counseling could be crucial among this population. In addition, those willing to use HIVST are also willing to use PrEP. It indicates that HIVST delivery could be incorporated into PrEP programs within the Brazilian Public Health System and eventually in Mexico and Peru.

Treponema pallidum genome sequencing from six continents reveals variability in vaccine candidate genes and dominance of Nichols clade strains in Madagascar

In spite of its immutable susceptibility to penicillin, Treponema pallidum (T. pallidum) subsp. pallidum continues to cause millions of cases of syphilis each year worldwide, resulting in significant morbidity and mortality and underscoring the urgency of developing an effective vaccine to curtail the spread of the infection. Several technical challenges, including absence of an in vitro culture system until very recently, have hampered efforts to catalog the diversity of strains collected worldwide. Here, we provide near-complete genomes from 196 T. pallidum strains-including 191 T. pallidum subsp. pallidum-sequenced directly from patient samples collected from 8 countries and 6 continents. Maximum likelihood phylogeny revealed that samples from most sites were predominantly SS14 clade. However, 99% (84/85) of the samples from Madagascar formed two of the five distinct Nichols subclades. Although recombination was uncommon in the evolution of modern circulating strains, we found multiple putative recombination events between T. pallidum subsp. pallidum and subsp. endemicum, shaping the genomes of several subclades. Temporal analysis dated the most recent common ancestor of Nichols and SS14 clades to 1717 (95% HPD: 1543-1869), in agreement with other recent studies. Rates of SNP accumulation varied significantly among subclades, particularly among different Nichols subclades, and was associated in the Nichols A subclade with a C394F substitution in TP0380, a ERCC3-like DNA repair helicase. Our data highlight the role played by variation in genes encoding putative surface-exposed outer membrane proteins in defining separate lineages, and provide a critical resource for the design of broadly protective syphilis vaccines targeting surface antigens.

Low socioeconomic status is associated with self-reported HIV positive status among young MSM in Brazil and Peru

BACKGROUND

Despite efforts to stop HIV epidemic in Latin America, new HIV cases continue to increase in the region especially among young MSM (YMSM). This study aims to assess if sociodemographic characteristics are associated with self-reported HIV positive status among YMSM from three Latin American countries.

METHODS

Cross-sectional web-based survey advertised on dating apps (Grindr and Hornet) and Facebook in Brazil, Mexico and Peru. For this analysis, we included YMSM aged 18-24 years who self-reported their HIV status. We used multivariable logistic regression models for each country separately to verify if sociodemographic characteristics (race, education and income) were associated with HIV self-reported status after adjusting for behavior characteristics (sexual attraction and steady partner).

RESULTS

Among 43,687 MSM who initiated the questionnaire, 27,318 (62.5%) reported their HIV status; 7001 (25.6%) of whom were YMSM. Most YMSM (83.4%) reported an HIV test in the past year, and 15.7% reported an HIV positive status in Peru, 8.4% in Mexico and 7.7% in Brazil. In adjusted models, low-income was associated with higher odds of self-reported HIV positive status in Brazil (aOR = 1.33, 95%CI: 1.01-1.75) and Peru (aOR = 1.56, 95%CI: 1.02-2.40), but not in Mexico. Lower education was associated with higher odds of self-reported HIV positive status only in Brazil (aOR = 1.35, 95%CI: 1.05-1.75).

CONCLUSIONS

In this large, cross-country study, self-reported HIV positive status among YMSM was high. Lower socioeconomic status was associated with higher odds of self-reported HIV positive status in Brazil and Peru. There is an urgent need for HIV prevention interventions targeting YMSM, and efforts to address low-income YMSM are especially needed in Peru and Brazil.

The Application of Cytokine Expression Assays to Differentiate Active From Previously Treated Syphilis

To investigate the role of serum cytokine assays to distinguish between active from treated syphilis among serofast patients, we recruited individuals into a prospective cohort study. Participants underwent routine syphilis screening. We selected specimens from a majority cohort of serofast participants with treated and active syphilis. We analyzed specimens with a 62-cytokine multiplex bead-based enzyme-linked immunosorbent assay. Cytokines, brain-derived neurotrophic factor and tumor necrosis factor β, were most predictive. We built a decision tree that was 82.4% accurate, 100% (95% confidence interval, 82%-100%) sensitive, and 45% (18%-75%) specific. Our decision tree differentiated between serum specimens from serofast participants with treated syphilis versus active syphilis.

Transcriptional and immunological analysis of the putative outer membrane protein and vaccine candidate TprL of Treponema pallidum

Background

An effective syphilis vaccine should elicit antibodies to Treponema pallidum subsp. pallidum (T. p. pallidum) surface antigens to induce pathogen clearance through opsonophagocytosis. Although the combination of bioinformatics, structural, and functional analyses of T. p. pallidum genes to identify putative outer membrane proteins (OMPs) resulted in a list of potential vaccine candidates, still very little is known about whether and how transcription of these genes is regulated during infection. This knowledge gap is a limitation to vaccine design, as immunity generated to an antigen that can be down-regulated or even silenced at the transcriptional level without affecting virulence would not induce clearance of the pathogen, hence allowing disease progression.

Principal findings

We report here that tp1031, the T. p. pallidum gene encoding the putative OMP and vaccine candidate TprL is differentially expressed in several T. p. pallidum strains, suggesting transcriptional regulation. Experimental identification of the tprL transcriptional start site revealed that a homopolymeric G sequence of varying length resides within the tprL promoter and that its length affects promoter activity compatible with phase variation. Conversely, in the closely related pathogen T. p. subsp. pertenue, the agent of yaws, where a naturally-occurring deletion has eliminated the tprL promoter region, elements necessary for protein synthesis, and part of the gene ORF, tprL transcription level are negligible compared to T. p. pallidum strains. Accordingly, the humoral response to TprL is absent in yaws-infected laboratory animals and patients compared to syphilis-infected subjects.

Conclusion

The ability of T. p. pallidum to stochastically vary tprL expression should be considered in any vaccine development effort that includes this antigen. The role of phase variation in contributing to T. p. pallidum antigenic diversity should be further studied.

Syphilis is still an endemic disease in many low- and middle-income countries and has been resurgent in high-income nations for almost two decades now. In endemic areas, syphilis still causes significant morbidity and mortality in patients, particularly when its causative agent, the bacterium Treponema pallidum subsp. pallidum is transmitted to the fetus during pregnancy. Although there are significant ongoing efforts to identify an effective syphilis vaccine to bring into clinical trials within the decade in the U.S., such efforts are partially hindered by the lack of knowledge on transcriptional regulation of many genes encoding vaccine candidates. Here, we start addressing this knowledge gap for the putative outer membrane protein (OMP) and vaccine candidates TprL, encoded by the tp1031 gene. As we previously reported for other putative OMP-encoding genes of the syphilis agent, tprL transcription level appears to be affected by the length of a homopolymeric sequence of guanosines (Gs) located within the gene promoter. This is a mechanism known as phase variation and often involved in altering the surface antigenic profile of a bacterial pathogen to facilitate immune evasion and/or adaptation to the host milieu.

Investigation of syphilis immunology and Treponema pallidum subsp. pallidum biology to improve clinical management and design a broadly protective vaccine: study protocol

BACKGROUND

The syphilis epidemic continues to cause substantial morbidity and mortality worldwide, particularly in low- and middle-income countries, despite several recent disease control initiatives. Though our understanding of the pathogenesis of this disease and the biology of the syphilis agent, Treponema pallidum subsp. pallidum has improved over the last two decades, further research is necessary to improve clinical diagnosis and disease management protocols. Additionally, such research efforts could contribute to the identification of possible targets for the development of an effective vaccine to stem syphilis spread.

METHODS

This study will recruit two cohorts of participants with active syphilis infection, one with de novo infection, one with repeat infection. Whole blood specimens will be collected from each study participant at baseline, 4, 12, 24, 36, and 48 weeks, to track specific markers of their immunological response, as well as to compare humoral reactivity to Treponema pallidum antigens between the two groups. Additionally, we will use serum specimens to look for unique cytokine patterns in participants with early syphilis. Oral and blood samples, as well as samples from any syphilitic lesions present, will also be collected to sequence any Treponema pallidum DNA found.

DISCUSSION

By furthering our understanding of syphilis pathogenesis and human host immune response to Treponema pallidum, we will provide important data that will help in development of new point-of-care tests that could better identify active infection, leading to improved syphilis diagnosis and management. Findings could also contribute to vaccine development efforts.

The development of an online risk calculator for the prediction of future syphilis among a high-risk cohort of men who have sex with men and transgender women in Lima, Peru

Background Syphilis incidence worldwide has rebounded since 2000, particularly among men who have sex with men (MSM). A predictive model for syphilis infection may inform prevention counselling and use of chemoprophylaxis.

METHODS

Data from a longitudinal cohort study of MSM and transgender women meeting high-risk criteria for syphilis who were followed quarterly for 2 years were analysed. Incidence was defined as a four-fold increase in rapid plasma reagin (RPR) titres or new RPR reactivity if two prior titres were non-reactive. Generalised estimating equations were used to calculate rate ratios (RR) and develop a predictive model for 70% of the dataset, which was then validated in the remaining 30%. An online risk calculator for the prediction of future syphilis was also developed.

RESULTS

Among 361 participants, 22.0% were transgender women and 34.6% were HIV-infected at baseline. Syphilis incidence was 19.9 cases per 100-person years (95% confidence interval (CI) 16.3-24.3). HIV infection (RR 2.22; 95% CI 1.54-3.21) and history of syphilis infection (RR 2.23; 95% 1.62-3.64) were significantly associated with incident infection. The final predictive model for syphilis incidence in the next 3 months included HIV infection, history of syphilis, number of male sex partners and sex role for anal sex in the past 3 months, and had an area under the curve of 69%. The online syphilis risk calculator based on those results is available at: www.syphrisk.net.

CONCLUSIONS

Using data from a longitudinal cohort study among a population at high risk for syphilis infection in Peru, we developed a predictive model and online risk calculator for future syphilis infection. The predictive model for future syphilis developed in this study has a moderate predictive accuracy and may serve as the foundation for future studies.

Factors Associated With Willingness to Use Pre-Exposure Prophylaxis in Brazil, Mexico, and Peru: Web-Based Survey Among Men Who Have Sex With Men

Background

HIV disproportionally affects key populations including men who have sex with men (MSM). HIV prevalence among MSM varies from 17% in Brazil and Mexico to 13% in Peru, whereas it is below 0.5% for the general population in each country. Pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir is being implemented in the context of combination HIV prevention. Reports on willingness to use PrEP among MSM have started to emerge over the last few years. Previously reported factors associated with willingness to use PrEP include awareness, higher sexual risk behavior, and previous sexually transmitted infection.

Objective

This study aimed to evaluate the factors associated with willingness to use daily oral PrEP among MSM in 3 Latin American, middle-income countries (Brazil, Mexico, and Peru).

Methods

This Web-based, cross-sectional survey was advertised in 2 gay social network apps (Grindr and Hornet) used by MSM to find sexual partners and on Facebook during 2 months in 2018. Inclusion criteria were being 18 years or older, cisgender men, and HIV-negative by self-report. Eligible individuals answered questions on demographics, behavior, and PrEP (awareness, willingness to use, barriers, and facilitators). Multivariable logistic regression modeling was performed to assess the factors associated with willingness to use daily oral PrEP in each country.

Results

From a total sample of 43,687 individuals, 44.54% of MSM (19,457/43,687) were eligible and completed the Web-based survey—Brazil: 58.42% (11,367/19,457), Mexico: 30.50% (5934/19,457), and Peru: 11.08% (2156/19,457); median age was 28 years (interquartile range: 24-34), and almost half lived in large urban cities. Most participants were recruited on Grindr (69%, 13,349/19,457). Almost 20% (3862/19,352) had never tested for HIV, and condomless receptive anal sex was reported by 40% (7755/19,326) in the previous 6 months. Whereas 67.51% (13,110/19,376) would be eligible for PrEP, only 9.80% (1858/18,959) of participants had high HIV risk perception. PrEP awareness was reported by 64.92% (12,592/19,396); this was lower in Peru (46.60%, 1002/2156). Overall, willingness to use PrEP was reported by 64.23% (12,498/19,457); it was highest in Mexico (70%, 4158/5934) and lowest in Peru (58%, 1241/2156). In multivariate regression models adjusted for age, schooling, and income in each country, willingness to use PrEP was positively associated with PrEP awareness and PrEP facilitators (eg, free PrEP and HIV testing) and negatively associated with behavioral (eg, concerned by daily pill regimen) and belief barriers (eg, sexual partners may expect condomless sex).

Conclusions

In this first cross-country, Web-based survey in Latin America, willingness to use PrEP was found to be high and directly related to PrEP awareness. Interventions to increase awareness and PrEP knowledge about safety and efficacy are crucial to increase PrEP demand. This study provides important information to support the implementation of PrEP in Brazil, Mexico, and Peru.

Cytokine expression in Treponema pallidum infection

BACKGROUND

Current syphilis tests cannot distinguish between active and past syphilis among patients with serofast rapid plasma reagin (RPR) titers. We investigated whether cytokine profiles might provide insight in the differentiation of active and treated syphilis.

METHODS

We collected quarterly serum samples from participants at risk for incident syphilis in a prospective cohort study of men and male-to-female transgender women. We defined incident syphilis as a new RPR titer ≥ 1:8 or a fourfold increase from a prior RPR titer and a positive Treponema pallidum particle agglutination assay. We measured cytokine expression using a 63-multiplex bead-based Luminex assay (eBiosciences/Affymetrix, San Diego, California, USA). We used tertile bins and Chi square tests to identify differences in proportions of cytokines between samples from patients with active and treated syphilis. We constructed a network of cytokine profiles from those findings. We used R software (R version 3.4.1, R, Vienna, Austria) to fit models.

RESULTS

We identified 20 pairs of cytokines (out of 1953 possible pairs) that differed between active and treated syphilis. From those, we identified three cytokine networks of interest: an Eotaxin-Rantes-Leptin network, a Mig-IL1ra-Trail-CD40L network, and an IL12p40-IL12p70 network.

CONCLUSIONS

Differences in cytokine profiles are present among men and male-to-female transgender women with active and treated syphilis. Cytokine assays may be a potentially useful tool for identifying active syphilis among patients with serologic syphilis reactivity.

Dual rapid test for HIV and syphilis: A laboratory evaluation of the diagnostic accuracy of the Standard Q HIV/Syphilis Combo Test

We evaluated the Standard Q HIV/Syphilis Combo Test (SD Biosensor, South Korea), a dual rapid test using stored sera (N = 400) in a laboratory setting in Lima, Peru. The sensitivity and specificity for HIV antibody detection was 100.0% (95% CI: 98.2-100.0%) and 99.5% (95% CI: 97.2-100.0%), respectively. For treponemal antibody detection the sensitivity and specificity was 97.5% (95%CI:94.3-99.2%) and 100.0% (95%CI:98.2-100.0%), respectively.

Venue-Based HIV-Testing: An Effective Screening Strategy for High-Risk Populations in Lima, Peru

Venue-based testing may improve screening efforts for HIV and syphilis, thereby reducing transmission. We offered onsite rapid dual HIV and syphilis testing at venues popular among MSM and/or transgender women in Lima, Peru. We used Poisson regression to calculate adjusted prevalence ratios (aPRs) for factors associated with each infection. Most (90.4%) of the 303 participants would test more frequently if testing was available at alternative venues. New cases of HIV (69) and syphilis infection (84) were identified. HIV was associated with recent sex work (aPR 1.11; 95% CI 1.02-1.22), sex with a partner of unknown serostatus (aPR 1.18; 95% CI 1.09-1.27), exclusively receptive anal sex role (aPR 1.16; 95% CI 1.03-1.30) or versatile sex role (aPR 1.17; 95% CI 1.06-1.30) compared to insertive. Syphilis was associated with reporting role versatility (aPR = 2.69; 95% CI 1.52-5.74). Sex work venues had higher syphilis prevalence 47% versus 28% in other venues, p value = 0.012. Venue-based testing may improve case finding.

Impact of pre-diagnosis awareness of HIV-related stigma and dispositional coping on linkage to HIV care among newly diagnosed HIV+ Peruvian patients

A substantial body of literature has characterized how psychosocial factors, including HIV-related stigma and coping, are associated with HIV testing and HIV care utilization post-diagnosis. Less is known about if certain psychosocial characteristics pre-diagnosis may also predict linkage to care among individuals who receive an HIV-positive diagnosis. We examined if pre-diagnosis awareness/perception about HIV-related stigma and dispositional coping styles predicted linkage to HIV care within three months post-diagnosis with a secondary analysis of 604 patients from a randomized controlled trial (Sabes Study). Awareness/perception about HIV-related stigma, dispositional maladaptive and adaptive coping were measured before patients underwent an HIV test. Linkage to care was measured as receipt of care within three months of receiving the diagnosis. After adjusting for covariates, individuals who reported greater dispositional maladaptive coping pre-diagnosis had lower odds of linking to care, OR = 0.82, 95%CI [0.67, 1.00], p = .05. There was also a non-significant inverse association between dispositional adaptive coping pre-diagnosis and linkage to care. These preliminary data suggest the need for further longitudinal research and highlight the potential utility of pre-diagnosis psychosocial assessment and tailored counseling when providing positive HIV diagnosis results.

HIV and syphilis testing preferences among men who have sex with men and among transgender women in Lima, Peru

BACKGROUND

Men who have sex with men (MSM) and transgender women in Peru are at high risk for acquiring syphilis and HIV infection. The World Health Organization highly recommends screening for HIV and syphilis to reduce morbidity and mortality associated with untreated infections. We aimed to identify factors associated with dual testing preferences for HIV and syphilis infection among MSM and transgender women in Lima, Peru.

METHODS

We used conjoint analysis, an innovative method for systematically estimating consumer preferences. We created eight hypothetical test profiles varying across six dichotomous attributes: cost (free vs. $4), potential for false positive syphilis result (no false positive vs. some risk of false positive), time-to-result (20 minutes vs. 1 week), blood draw method (finger prick vs. venipuncture), test type (rapid vs. laboratory), and number of draws (1 vs. 2). We fit a conjoint analysis model for each participant using a simple main effects ANOVA. Attribute importance values were calculated using percentages from relative ranges in the attribute's utility values. Results were summarized across participants and averages were reported.

RESULTS

We recruited 415 MSM/transgender women over 18 years of age from two STD clinics in Lima, Peru. No potential for syphilis false positive result (no false positive vs. some potential for false positive) had the largest average impact on willingness to use the test and on average accounted for 23.8% of test type preference, followed by cost (free vs. ~USD$4; 21.6%), time to results (20 minutes vs. 1 week; 17.4%), number of blood draws (1 draw vs. 2 draws; 13.8%), method of blood draw (fingerprick vs. venipuncture; 13.7%), and test type (rapid POC vs. laboratory; 9.7%).

CONCLUSION

MSM/transgender women in Peru prioritized accuracy, cost, timeliness and number of blood draws for HIV and syphilis testing. Implementing a low cost, accurate, rapid and dual testing strategy for HIV and syphilis could improve screening uptake and accessibility of testing to accelerate time to treatment.

Field evaluation of a smartphone-based electronic reader of rapid dual HIV and syphilis point-of-care immunoassays

OBJECTIVE

Electronic (E) devices read and quantify lateral flow-based rapid tests, providing a novel approach to assay interpretation. We evaluated the performance of one E-reader for two dual HIV and syphilis immunoassays.

METHODS

We enrolled men who have sex with men and transgender women >18 years of age seeking medical services at an STD clinic in Lima, Peru, between October 2016 and April 2017. Venous blood was tested using two dual HIV and syphilis antibody immunoassays (SD BIOLINE HIV/Syphilis Duo, Republic of Korea, and First Response HIV 1+2/Syphilis Combo, India). Reference testing included a fourth-generation ELISA for HIV antibodies and use of the Treponema pallidum particle agglutination assay for syphilis antibodies. Trained clinic staff visually inspected the immunoassay results, after which the immunoassays were read by the HRDR-200 E-reader (Cellmic, USA), an optomechanical smartphone attachment. We calculated the concordance of the E-reader with visual inspection, as well as the sensitivity of both rapid immunoassays, in detecting HIV and T. pallidum antibodies.

RESULTS

On reference testing of 283 participant specimens, 34% had HIV antibodies and 46% had T. pallidum antibodies. Using First Response, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T . pallidum and 97% (95% CI 95% to 99%) for HIV antibodies. Using SD BIOLINE, the concordance of the E-reader with visual inspection was 97% (95% CI 94% to 99%) for T. pallidum and 99% (95% CI 98% to 99%) for HIV antibodies. For both immunoassays, the sensitivity for HIV antibodies was 98% (95% CI 93% to 100%) and the sensitivity for T. pallidum antibodies was 81% (95% CI 73% to 87%).

CONCLUSIONS

E-reader results correlated well with visual inspection. The sensitivities of both rapid assays were comparable with past reports. Further evaluation of the E-reader is warranted to investigate its utility in data collection, monitoring and documentation of immunoassay results.

The Relationship Between Risk Perception and Frequency of HIV Testing Among Men Who Have Sex with Men and Transgender Women, Lima, Peru

HIV infections in Peru are concentrated among men who have sex with men (MSM) and transgender women (TW). HIV testing rates among them remain low, delaying entrance into care. We assessed the prevalence of frequent HIV testing (at least every 6 months) and associated factors among 310 MSM and TW who attend sexual health clinics in Lima, Peru, and who reported that they were HIV seronegative or unaware of their status. Only 39% of participants tested frequently, and 22% had never tested; 29% reported that they were at low or no risk for acquiring HIV. Reporting low or no risk for acquiring HIV was associated with frequent testing (adjusted prevalence ratio [aPR] = 1.53, 95% CI 1.13-2.08); those reporting unprotected anal sex were less likely to test frequently (aPR = 0.66, 95% CI 0.50-0.87). HIV prevalence was 12% and did not vary by risk perception categories. This at-risk population tests infrequently and may not understand the risk of having unprotected sex.

Perceptions Prediagnosis and Social Experiences Postdiagnosis Among a Sample of High-Risk Peruvian Men Who Have Sex With Men

This pilot study examines associations of perceived stigma pre-diagnosis with experienced stigma and social support post-diagnosis with qualitative data; and quantifies the interplay between pre- and post-diagnosis social factors on depressive symptoms among a sample of newly diagnosed Peruvian men who have sex with men (n = 67 total). Qualitative findings highlight the differences between perceptions of stigma pre-disclosure and actual social experiences post-disclosure for most participants. Perceived stigma pre-diagnosis was significantly related to post-diagnosis social support, B = -0.35, p = 0.03, and marginally associated with experienced stigma, B = 0.29, p = 0.07. Pre-diagnosis perceived stigma was associated with greater depressive symptoms, but only among individuals who reported higher amounts of social support, B = 0.55, p = 0.01. Findings suggest the importance of addressing social perceptions in order to optimize the beneficial effects of social support resources among newly diagnosed individuals.

Patient-nominated supporters as facilitators for engagement in HIV care in a referral hospital in Peru: A retrospective cohort study

Patient-nominated supporters can potentially improve the continuum of HIV care. We retrospectively determined factors associated with having a patient-nominated supporter among people living with HIV (PLWH), and its association with retention in care and viral suppression. We analysed registries of adults evaluated by social workers (n = 1345) at a referral hospital in Peru between 2011–2014. Nondisclosure of HIV status was associated with lacking supporters (aPR: 5.41, 95% CI: 3.83–7.64). Retention in care was 76.4% and 34.2% after one and two years of enrolment, respectively. PLWH with supporters were more likely to be retained in care after two years (aRR = 1.36, 95% CI: 1.02–1.81), but not after one year (aRR = 1.10, 95% CI: 0.98–1.23) compared to PLWH without supporters. Having supporters who were parents or friends was associated with an increased probability of being retained in care after one and two years of enrolment. Viral suppression after one year of enrolment was 58.7%. Having a supporter was not associated with viral suppression (aRR = 1.18, 95% CI: 0.99–1.41), but PLWH with supporters were more likely to have viral load measurements (p = 0.005). Patient-nominated supporters appear beneficial for engagement in HIV care; these benefits may be related to the nature of their relationship with PLWH.

High incidence of extra-genital gonorrheal and chlamydial infections among high-risk men who have sex with men and transgender women in Peru

Extra-genital Neisseria gonorrhoeae and Chlamydia trachomatis infections are associated with antimicrobial resistance and HIV acquisition. We analyzed data from a cohort of men who have sex with men (MSM) and transgender women followed quarterly for two years in Peru. Incident cases were defined as positive N. gonorrhoeae or C. trachomatis nucleic acid tests during follow-up. Repeat positive tests were defined as reinfection among those with documented treatment. We used generalized estimating equations to calculate adjusted incidence rate ratios (aIRRs). Of 404 participants, 22% were transgender. Incidence rates of rectal N. gonorrhoeae and C. trachomatis infection were 28.1 and 37.3 cases per 100 person-years, respectively. Incidence rates of pharyngeal N. gonorrhoeae and C. trachomatis infection were 21.3 and 9.6 cases per 100 person-years, respectively. Incident HIV infection was associated with incident rectal (aIRR = 2.43; 95% CI 1.66-3.55) N. gonorrhoeae infection. Identifying as transgender versus cisgender MSM was associated with incident pharyngeal N. gonorrhoeae (aIRR = 1.85; 95% CI 1.12-3.07) infection. The incidence of extra-genital N. gonorrhoeae and C. trachomatis infections was high in our population. The association with incident HIV infection warrants evaluating the impact of rectal N. gonorrhoeae screening and treatment on HIV transmission.

Do Subjective Alcohol Screening Tools Correlate with Biomarkers Among High-Risk Transgender Women and Men Who Have Sex with Men in Lima, Peru?

Alcohol abuse can influence sexual risk behavior; however, its measurement is not straightforward. This study compared self-reported alcohol use, via the AUDIT and CAGE, with levels of phosphatidylethanol (Peth), a phospholipid biomarker that forms with chronic, heavy drinking, among high-risk MSM and TW in Lima, Peru. Chi square, Fisher's exact, Wilcoxon ranksum tests compared the instruments. Receiver operating curves determined sensitivity and specificity of the self-reported measures. Among 69 MSM and 17 TW, PEth was positive for 86% (95% CI 77-93%) of participants, while 67% reported binge-drinking in the last 2 weeks. The AUDIT classified 25% as hazardous drinkers while CAGE identified 6% as problem drinkers. Self-reported binge drinking was more sensitive than the AUDIT for PEth positivity (71% vs. 27%, p = 0.022). Among high-risk MSM and TW in Lima, validated, self-report measures of alcohol abuse underestimated biological measures. Further research correlating bio-markers and self-reported alcohol abuse measures is needed.

Transient aortitis documented by positron emission tomography in a case series of men and transgender women infected with syphilis

OBJECTIVES

Syphilis infection persists globally contributing to preventable and treatable morbidity and mortality. How extensive early syphilis disseminates is unknown. To better understand the relationship between early syphilis infection and inflammation over time, our study enrolled six individuals recently infected with syphilis for sequential positron emission tomography (PET) scans.

METHODS

We evaluated a case series of six individuals with high syphilis titres (two secondary, two early latent and two latent, unknown duration, but with high titre) who received sequential PET scans to assess inflammation over time and its response to treatment.

RESULTS

At time of PET scan, four of the six individuals were co-infected with HIV. One of the four was not on antiretroviral therapy and three of the four were not virally suppressed (viral load of >400 copies/mL). Baseline rapid plasma reagin (RPR) titres ranged from 1:64 to 1:256 (four of the six participants had prior non-reactive RPR results). Five of the six participants had mild to intense hypermetabolic PET scan activity consistent with cervical (n=5), axillary (n=4), inguinal (n=5) and retroperitoneal (n=1) adenopathy. Mild hypermetabolic activity in the thoracic aortic wall, suggesting aortitis, was present among the same five participants and resolved within 30 days for four of the five participants and 60 days for the other participant. However, widespread lymphadenopathy remained present in PET scans up to 3 months following treatment in two participants. We did not find any abnormal PET scan activity of the central nervous system.

CONCLUSION

We found abnormal aortic wall PET scan activity suggesting aortitis to be common in a case series of patients with early syphilis. In research settings, PET scans may be a sensitive tool to monitor inflammation associated with syphilis.

Plagiarism, Cheating and Research Integrity: Case Studies from a Masters Program in Peru

Plagiarism is a serious, yet widespread type of research misconduct, and is often neglected in developing countries. Despite its far-reaching implications, plagiarism is poorly acknowledged and discussed in the academic setting, and insufficient evidence exists in Latin America and developing countries to inform the development of preventive strategies. In this context, we present a longitudinal case study of seven instances of plagiarism and cheating arising in four consecutive classes (2011-2014) of an Epidemiology Masters program in Lima, Peru, and describes the implementation and outcomes of a multifaceted, "zero-tolerance" policy aimed at introducing research integrity. Two cases involved cheating in graded assignments, and five cases correspond to plagiarism in the thesis protocol. Cases revealed poor awareness of high tolerance to plagiarism, poor academic performance, and widespread writing deficiencies, compensated with patchwriting and copy-pasting. Depending on the events' severity, penalties included course failure (6/7) and separation from the program (3/7). Students at fault did not engage in further plagiarism. Between 2011 and 2013, the Masters program sequentially introduced a preventive policy consisting of: (i) intensified research integrity and scientific writing education, (ii) a stepwise, cumulative writing process; (iii) honor codes; (iv) active search for plagiarism in all academic products; and (v) a "zero-tolerance" policy in response to documented cases. No cases were detected in 2014. In conclusion, plagiarism seems to be widespread in resource-limited settings and a greater response with educational and zero-tolerance components is needed to prevent it.

Men Who Have Sex With Men in Peru: Acceptability of Medication-Assisted Therapy for Treating Alcohol Use Disorders

In Peru, the HIV epidemic is concentrated in men who have sex with men (MSM) and transgender women (TGW). Multiple studies correlate alcohol use disorders (AUDs) with risky sexual behaviors among Peruvian MSM. Qualitative research was used to inform a clinical trial on the acceptability of medication-assisted therapies to assist management of AUDs and improve antiretroviral therapy (ART) adherence among MSM/TGW in Peru. Three focus groups involving HIV-infected or HIV-uninfected MSM/TGW ( n = 26) with AUDs (AUDIT ≥ 8) were transcribed, translated from Spanish into English, and analyzed using thematic content analysis. Despite having an AUD, participants considered themselves "social" drinkers, minimized their drinking behaviors, and differed about whether or not alcohol problems could be treated. Participants expressed skepticism about medication for treating AUDs. Three concepts emerged as necessary components of a treatment program for alcohol problems: cost, family support, and the potential to drink less alcohol without attaining total abstinence. This study reveals important areas of education to increase potential acceptability of a medication for treating AUDs among MSM/TGW. Given the social conditions and knowledge base of the participants, medication-assisted therapies using naltrexone may be a beneficial strategy for MSM with AUDs.

A Qualitative Assessment of Alcohol Consumption and Sexual Risk Behaviors Among Men Who Have Sex With Men and Transgender Women in Peru

BACKGROUND

Peruvian men who have sex with men (MSM) and transgender women (TGW) experience the double burden of a highly concentrated HIV epidemic with a high prevalence of alcohol use disorders (AUDs). Recent research has associated both with risky sexual behaviors, including unprotected sex, having multiple sexual partners, engaging in sex work, having recent sexually transmitted infections, and having HIV-infected partners. AUDs have also been associated in MSM/TGW with being unaware of HIV+ status.

OBJECTIVES

This study aims to further examine issues associated with alcohol consumption, HIV infection, and risk behaviors in a qualitative analysis of focus groups conducted with MSM/TGW in Peru.

METHODS

A total of 26 MSM/TGW participants with AUDs participated in three semi-structured focus groups in Lima, Peru. Content analysis was facilitated by software, and specific themes were elucidated.

RESULTS

Participants described their drinking patterns, including the types of alcoholic drinks they consumed. They depicted drinking frequently and over multiple-day sessions. Problematic drinking behaviors were described, as well as the perceived characteristics of alcohol dependence. Interestingly, HIV-infected participants who were prescribed antiretroviral therapy did not believe that their drinking affected their medication adherence. These insights can aid in the design of future interventions aiming to reduce problematic drinking as well as HIV-related risk behaviors and, subsequently, HIV incidence.

CONCLUSIONS

Peruvian MSM/TGW exhibit problematic drinking, which may be associated with risky sexual behaviors and HIV transmission. Interest in reducing alcohol consumption was high, suggesting the need for targeted behavioral and pharmacological interventions.

The PICASSO Cohort: baseline characteristics of a cohort of men who have sex with men and male-to-female transgender women at high risk for syphilis infection in Lima, Peru

BACKGROUND

Men who have sex with men (MSM) and male-to-female transgender women (transwomen) are disproportionately at risk of syphilis infection in Peru.

METHODS

From 2013 to 2014, MSM and transwomen seeking human immunodeficiency virus (HIV) or sexually transmitted infection (STI) testing and/or treatment were recruited into a 2-year observational cohort study to determine predictors of recently acquired syphilis infection (defined as a rapid plasma reagin [RPR] titer ≥1:16 and a reactive treponemal antibody test) in Lima, Peru. At baseline, interviewers collected sociodemographic, behavioral, and medical characteristics from participants. All cohort participants were tested for syphilis, HIV, Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) infection. Using cross-sectional analyses, bivariate and multivariate models were used to determine factors associated with recently acquired syphilis infection and calculate adjusted prevalence ratios.

RESULTS

We recruited 401 participants, 312 MSM and 89 transwomen, with median ages of 29.0 and 32.5 years old (interquartile ranges: 23.3, 37.4 and 27.2, 39.5, respectively). The prevalence of recently acquired syphilis infection at baseline was 16.8% for MSM and 6.7% for transwomen. Among MSM and transwomen, 30.1 and 33.7% were infected with HIV, 18.6 and 24.7% were infected with CT, and 14.2 and 19.1% were infected with NG, respectively. Co-infection rates among MSM with recently acquired syphilis infection included: 44.2% with HIV, 40.4% with CT (32.7% with anal CT and 7.7% with pharyngeal CT), and 19.2% with NG (11.5% with anal NG and 7.7% with pharyngeal NG). Co-infection rates among transwomen with recently acquired syphilis infection included: 66.7% with HIV, 0% with CT, and 16.7% with anal NG. In multivariate analysis among the entire cohort, recently acquired syphilis infection was independently associated with younger age (adjusted prevalence ratio [aPR] = 0.96, 95% confidence interval [CI] = 0.93-0.99), receptive role during anal sex (aPR = 2.56, 95% CI = 1.05-6.25), prior HIV diagnosis (aPR = 1.70, 95% CI = 1.11-2.61), anal CT or NG infection (aPR = 1.69, 95% CI = 1.09-2.60), and prior syphilis diagnosis (aPR = 3.53, 95% CI = 2.20-5.68).

CONCLUSIONS

We recruited a cohort of MSM and transwomen who had a high prevalence of recently acquired syphilis infection in Lima, Peru. Recently acquired syphilis infection was associated with socio-demographic characteristics, sexual risk, and sexually transmitted co-infections.

HIV Status Communication with Sex Partners and Associated Factors Among High-Risk MSM and Transgender Women in Lima, Peru

Men who have sex with men (MSM) and transgender women (TW) are key populations in the HIV epidemic. HIV status communication between sex partners can inform decisions regarding sexual behavior. MSM and TW were asked about HIV status communication with sex partners at baseline, 9- and 18-months. GEE models assessed associations with HIV status communication at baseline using prevalence ratios (PRs) and longitudinally using odds ratios (ORs). At baseline, those who had previously had an HIV test, disclosed their HIV status to 42 % of their sex partners. HIV status communication was associated with knowing their sex partner's HIV status at baseline (aPR 5.20) and longitudinally (aOR 1.86). HIV positivity at baseline was negatively associated with HIV status communication during follow-up (aOR 0.55). All reported aPRs and aORs have p < 0.05. Interventions promoting HIV status communication and more frequent HIV testing should be explored as current efforts are insufficient.

Factors associated with previously undiagnosed human immunodeficiency virus infection in a population of men who have sex with men and male-to-female transgender women in Lima, Peru

The aim of the study was to identify factors associated with undiagnosed human immunodeficiency virus (HIV) infection among men who have sex with men (MSM) and male-to-female transgender women in Lima, Peru.We analyzed characteristics of 378 MSM and transgender women recruited from 2 sexually transmitted infection (STI) clinics in Lima, Peru. Descriptive analyses compared: (A) HIV-uninfected, (B) previously undiagnosed HIV-infected, and (C) previously diagnosed HIV-infected participants. Multivariable logistic regression models identified: (1) correlates of previously undiagnosed HIV-infection among participants thought to be HIV-uninfected (B vs A); and (2) correlates of previously undiagnosed HIV-infection among HIV-infected participants (B vs C). Subanalysis identified correlates of frequent HIV testing among participants thought to be HIV-uninfected.Among participants, 31.0% were HIV-infected; of those, 35.0% were previously undiagnosed. Among participants thought to be HIV-uninfected (model 1), recent condomless receptive anal intercourse and last HIV test being over 1-year ago (compared to within the last 6-months) were associated with increased odds of being previously undiagnosed HIV-infected (adjusted odds ratio [aOR] = 2.43, 95% confidence interval [95%CI] = 1.10-5.36; aOR = 2.87, 95%CI = 1.10-7.53, respectively). Among HIV-infected participants (model 2), recent condomless receptive anal intercourse was again associated with previously undiagnosed HIV-infection (aOR = 2.54, 95%CI = 1.04-6.23). Achieving post-secondary education and prior syphilis infection were associated with lower odds of having previously undiagnosed HIV-infection (aOR = 0.35, 95%CI = 0.15-0.81; aOR = 0.32, 95%CI = 0.14-0.75, respectively).Reporting semiannual testing was associated with higher educational attainment, identifying as a transgender woman, or reporting a history of syphilis (aOR = 1.94, 95%CI = 1.11-3.37; aOR = 2.40, 95%CI = 1.23-4.70; aOR = 2.76, 95%CI = 1.62-4.71, respectively). Lower odds of semiannual testing were associated with recent condomless insertive anal intercourse or reporting a moderate or high self-perceived risk of acquiring HIV (aOR = 0.56, 95%CI = 0.33-0.96; aOR = 0.32, 95%CI = 0.18-0.59 and aOR = 0.43, 95%CI = 0.21-0.86, respectively).In our study, undiagnosed HIV-infection was associated with recent condomless receptive anal intercourse, infrequent HIV testing, lower education, and absence of prior syphilis diagnosis. Infrequent HIV testing was associated with lower education, not identifying as transgender, recent condomless insertive anal intercourse, absence of prior syphilis diagnosis, and higher self-perceived risk of HIV. Further efforts to decrease HIV transmission and increase HIV-serostatus awareness should be directed towards effectively promoting condom use and frequent HIV testing, integrated with STI management.

Risk Factors Associated with Incident Syphilis in a Cohort of High-Risk Men in Peru

BACKGROUND

Syphilis is concentrated among high-risk groups, but the epidemiology of syphilis reinfection is poorly understood. We characterized factors associated with syphilis incidence, including reinfection, in a high-risk cohort in Peru.

METHODS

Participants in the NIMH CPOL trial were assessed at baseline and 2 annual visits with HIV/STI testing and behavioral surveys. Participants diagnosed with syphilis also attended 4- and 9-month visits. All participants underwent syphilis testing with RPR screening and TPPA confirmation. Antibiotic treatment was provided according to CDC guidelines. Reinfection was defined as a 4-fold titer increase or recurrence of seroreactivity after successful treatment with subsequent negative RPR titers. The longitudinal analysis used a Possion generalized estimating equations model with backward selection of variables in the final model (criteria P <0.02).

RESULTS

Of 2,709 participants, 191 (7.05%) were RPR-reactive (median 1:8, range 1:1-1:1024) with TPPA confirmation. There were 119 total cases of incident syphilis, which included both reinfection and first-time incident cases. In the bivariate analysis, the oldest 2 quartiles of age (incidence ratio (IR) 3.84; P <0.001 and IR 8.15; P <0.001) and being MSM/TW (IR 6.48; P <0.001) were associated with higher risk of incident syphilis infection. Of the sexual risk behaviors, older age of sexual debut (IR 12.53; P <0.001), not being in a stable partnership (IR 1.56, P = 0.035), higher number of sex partners (IR 3.01; P <0.001), unprotected sex in the past 3 months (IR 0.56; P = 0.003), HIV infection at baseline (IR 3.98; P <0.001) and incident HIV infection during the study period (IR 6.26; P = 0.003) were all associated with incident syphilis. In the multivariable analysis, older age group (adjusted incidence ratio (aIR) 6.18; P <0.001), men reporting having sex with a man (aIR 4.63; P <0.001), and incident HIV infection (aIR 4.48; P = 0.008) were significantly associated.

CONCLUSIONS

We report a high rate of syphilis reinfection among high-risk men who have evidence of previous syphilis infection. Our findings highlight the close relationship between HIV incidence with both incident syphilis and syphilis reinfection. Further studies on syphilis reinfection are needed to understand patterns of syphilis reinfection and new strategies beyond periodic testing of high-risk individuals based on HIV status are needed.

HIV self-testing in Peru: questionable availability, high acceptability but potential low linkage to care among men who have sex with men and transgender women

HIV status awareness is key to prevention, linkage-to-care and treatment. Our study evaluated the accessibility and potential willingness of HIV self-testing among men who have sex with men (MSM) and transgender women in Peru. We surveyed four pharmacy chains in Peru to ascertain the commercial availability of the oral HIV self-test. The pharmacies surveyed confirmed that HIV self-test kits were available; however, those available were not intended for individual use, but for clinician use. We interviewed 147 MSM and 45 transgender women; nearly all (82%) reported willingness to perform the oral HIV self-test. However, only 55% of participants would definitely seek a confirmatory test in a clinic after an HIV-positive test result. Further, price may be a barrier, as HIV self-test kits were available for 18 USD, and MSM and transgender women were only willing to pay an average of 5 USD. HIV self-testing may facilitate increased access to HIV testing among some MSM/transgender women in Peru. However, price may prevent use, and poor uptake of confirmatory testing may limit linkage to HIV treatment and care.

High prevalence of extra-genital chlamydial or gonococcal infections among men who have sex with men and transgender women in Lima, Peru

Chlamydia trachomatis and Neisseria gonorrhoeae are among the most common sexually transmitted bacterial infections in the world. Data are limited, however, on the burden of extra-genital chlamydial and gonococcal infections among men who have sex with men and transgender women in Lima, Peru. Data were gathered from self-collected anal or pharyngeal swabs from participants in Lima, Peru, and analyzed via cross-sectional methods. Prevalence ratios for the association between extra-genital infection with socio-demographic and sexual behaviors were determined. Overall, 127 (32.8%) participants had anal or pharyngeal infections. On multivariate modeling, anal infection was positively associated with practicing both receptive and insertive anal sex, when compared to insertive alone (PR = 2.49; 95% CI = 1.32-4.71), and negatively associated with any antibiotic use in the prior three months (PR = 0.60; 95% CI = 0.39-0.91). Pharyngeal infection was negatively associated with age greater than 30 years compared to 18-30 years (PR = 0.54; 95% CI = 0.30-0.96), and positively associated with gender identity of transgender women (PR = 2.12; 95% CI = 1.20-3.73). This study demonstrates considerable burden of extra-genital chlamydial and gonococcal infections among men who have sex with men and transgender women in Lima, Peru.

Peru's HIV care continuum among men who have sex with men and transgender women: opportunities to optimize treatment and prevention

The HIV epidemic in Peru is concentrated in men who have sex with men (MSM) and transgender women (TW), who have an estimated prevalence > 10%, while the overall population prevalence remains < 1%. Because MSM and TW account for >60% of new infections, it is crucial to understand the full HIV continuum of care for these key populations. We performed a review of the peer-reviewed scientific and grey literature to determine the proportion of HIV-infected MSM and TW in Peru who are diagnosed, linked to and retained in care, are taking antiretroviral therapy (ART), and who have attained virologic suppression. Of the estimated 613,080 MSM and TW in Peru in 2015, approximately 63,981 are HIV-infected. Only 24.0% of HIV-infected MSM and TW are aware of their diagnosis, 15.6% are retained in care, 13.6% are on ART, and 12.0% have achieved adequate virologic control. The largest drop-off in the HIV care continuum occurs at the first step: diagnosis of HIV. Improving HIV serostatus awareness among MSM and TW is crucial to controlling Peru's HIV epidemic. In the era of 'treatment as prevention', understanding the full HIV care continuum may help guide efforts to curb transmission and reduce HIV-related morbidity and mortality.

Impact of alcohol use on sexual behavior among men who have sex with men and transgender women in Lima, Peru

BACKGROUND

Alcohol use disorders (AUDs) may enhance the likelihood of risky sexual behaviors and the acquisition of sexually transmitted infections (STIs). Associations between AUDs with condomless anal intercourse (CAI) and STI/HIV prevalence were assessed among men who have sex with men (MSM) and transgender women (TW) in Lima, Peru.

METHODS

MSM and TW were eligible to participate based on a set of inclusion criteria which characterized them as high-risk. Participants completed a bio-behavioral survey. An AUDIT score ≥8 determined AUD presence. Recent STI diagnosis included rectal gonorrhea/chlamydia, syphilis, and/or new HIV infection within 6 months. Prevalence ratios (PR) were calculated using Poisson regression.

RESULTS

Among 312 MSM and 89 TW, 45% (181/401) had an AUD. Among those with an AUD, 164 (91%) were hazardous/harmful drinkers, and 17 (9%) had alcohol dependence. Higher CAI was reported by participants with an AUD vs. without, (82% vs. 72% albeit not significant). Reporting anal sex in two or more risky venues was associated with screening AUD positive vs. not (24% vs. 15%, p=0.001). There was no difference in recent STI/HIV prevalence by AUD status (32% overall). In multivariable analysis, screening AUD positive was not associated with CAI or recent STI/HIV infection.

CONCLUSIONS

In our sample AUDs were not associated with CAI or new HIV infection/recent STI. However higher prevalence of CAI, alcohol use at last sex, and anal sex in risky venues among those with AUDs suggests that interventions to reduce the harms of alcohol should be aimed toward specific contexts.

High prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infections in anal and pharyngeal sites among a community-based sample of men who have sex with men and transgender women in Lima, Peru

OBJECTIVES

This study aimed to characterise the epidemiology of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections among men who have sex with men (MSM) and transgender women (TW) in Lima, Peru.

SETTING

Cross-sectional study in Lima, Peru.

PARTICIPANTS

We recruited a group of 510 MSM and 208 TW for a subsequent community-based randomised controlled trial. The presence of CT and NG were evaluated using Aptima Combo2 in pharyngeal and anal swabs. We also explored correlates of these infections.

PRIMARY AND SECONDARY OUTCOME MEASURES

Study end points included overall prevalence of C. trachomatis and N. gonorrhoeae in anal and pharyngeal sites.

RESULTS

Overall prevalence of CT was 19% (95% CI 16.1% to 22.1%) and 4.8% (95% CI 3.3% to 6.6%) in anal and pharyngeal sites, respectively, while prevalence of NG was 9.6% (95% CI 7.5% to 12.0%) and 6.5% (95% CI 4.8% to 8.5%) in anal and pharyngeal sites, respectively.

CONCLUSIONS

The prevalence of each infection declined significantly among participants older than 34 years (p<0.05). Efforts towards prevention and treatment of extraurogenital chlamydial and gonococcal infections in high-risk populations like MSM and TW in Lima, Peru, are warranted.

TRIAL REGISTRATION NUMBER

NCT00670163; Results.