Higher risk behaviour and rates of sexually transmitted diseases in Mwanza compared to Uganda may help explain HIV prevention trial outcomes

High burden of untreated syphilis, drug resistant Neisseria gonorrhoeae, and other sexually transmitted infections in men with urethral discharge syndrome in Kampala, Uganda

OBJECTIVES

Prompt diagnosis and treatment of sexually transmitted infections (STIs) are essential to combat the STI epidemic in resource-limited settings. We characterized the burden of 5 curable STIs chlamydia, gonorrhea, trichomoniasis, Mycoplasma genitalium, syphilis, and HIV infection in Ugandan men with urethritis.

METHODS

Participants were recruited from a gonococcal surveillance program in Kampala, Uganda. Questionnaires, penile swabs were collected and tested by nucleic acid amplification. Gonococcal isolates were tested for antimicrobial sensitivity. Sequential point-of-care tests on blood samples were used to screen for syphilis and HIV. Bivariable and multivariable multinomial logistic regression models were used to estimate odds ratios for preselected factors likely to be associated with STIs. Adherence to STI treatment guidelines were analyzed.

RESULTS

From October 2019 to November 2020, positivity (95% CI) for gonorrhea, chlamydia, trichomoniasis, and Mycoplasma genitalium, were 66.4% (60.1%, 72.2%), 21.7% (16.8%, 27.4%), 2.0% (0.7%, 4.9%), and 12.4% (8.7%, 17.3%) respectively. All Neisseria gonorrhoeae isolates were resistant to ciprofloxacin, penicillin, and tetracycline, but susceptible to extended spectrum cephalosporins and azithromycin. HIV and syphilis prevalence was 20.0% (50/250) and 10.0% (25/250), and the proportion unaware of their infection was 4.0% and 80.0% respectively. Most participants were treated per national guidelines. Multivariable analysis demonstrated significant associations between curable STI coinfections and younger age, transactional sex, but not HIV status, nor condom or alcohol use.

CONCLUSIONS

STI coinfections including HIV their associated risk factors, and gonococcal AMR were common in this population. The majority with syphilis were unaware of their infection and were untreated. Transactional sex was associated with STI coinfections, and > 80% of participants received appropriate treatment.

Prevalence of sexually transmitted infections in female clinic attendees in Honiara, Solomon Islands

OBJECTIVES

This study sought to determine the prevalence of common bacterial sexually transmitted infections, including Chlamydia trachomatis and Neisseria gonorrhoeae, in women attending clinics in the Solomon Islands.

METHODS

We conducted a sexual health survey among women attending three nurse-led community outpatient clinics in August 2014, to establish the prevalence of bacterial sexually transmitted infections in female clinic attenders in Honiara, Solomon Islands. Vaginal swab samples were tested for infection with C. trachomatis and N. gonorrhoeae using a commercial strand displacement amplification assay. Serum samples were tested for syphilis.

RESULTS

We enrolled 296 women, aged 16-49, attending three clinics. Knowledge of safe sexual practices was high but reported condom usage was low. The prevalence of infection with C. trachomatis was 20%. The prevalence of infection with N. gonorrhoeae and syphilis were 5.1% and 4.1%, respectively.

CONCLUSIONS

Bacterial sexually transmitted infections are a major health problem in the Solomon Islands. Interventions are urgently needed.

Incidence and trends in Burkitt lymphoma in northern Tanzania from 2000 to 2009

INTRODUCTION

Burkitt lymphoma (BL) is endemic in parts of Tanzania, but there is scant country or region level data about burden and trends of BL in Tanzania over the past three decades. Here, we update baseline epidemiology of BL in northern Tanzania using recent data.

PROCEDURE

Data for childhood BL diagnosed at six hospitals in Mara and Mwanza regions in northern Tanzania during 2000-2009 were compiled. Age, sex, and regional patterns were analyzed. Crude incidence rates of BL were calculated by sex, anatomic site, geographical region, and calendar year.

RESULTS

Among 944 cases, 549 (58%) were male (male/female case ratio 1.4:1). Among those with known anatomic site (92%), facial only tumors represented a large proportion of tumors in boys than girls (50% vs. 36%, P < 0.002). Tumors occurred at a younger mean age in boys than girls (6.8 years vs. 7.6 years, P < 0.01). Crude BL incidence was 4.2 per 100,000, but varied by region (3.0 in Mwanza vs. 6.8 in Mara, P = 0.01), by district (1.4-22), by gender (5.0 in boys vs. 4.0 in girls), and by age group (2.0 in 0-4, 7.8 in 5-9, and 3.1 in 10-15 years). BL incidence peaked in 2001 and decreased gradually thereafter.

CONCLUSIONS

Our results indicate that male sex, young age, and geographical characteristics are risk factors for BL in Tanzania. BL incidence declined with calendar year, but the significance of this finding is uncertain. Well-designed epidemiological studies of BL in Tanzania may shed light on environmental characteristics underlying these patterns.

The impact of mobility on HIV control: a modelling study

Mobility is associated with HIV due to more risky sexual behaviour of mobile groups such as travellers and migrants. Limited participation of such groups may reduce the effectiveness of HIV interventions disproportionally. The established STDSIM model, which simulates transmission and control of HIV and STD, was extended to simulate mobility patterns based on data from Tanzania. We explored the impact of non-participation of mobile groups (travellers and recent migrants) on the effectiveness of two interventions: condom promotion and health education aiming at partner reduction. If mobile groups do not participate, the effectiveness of both interventions could be reduced by 40%. The impact of targeting travellers with a combined HIV campaign is close to that of a general population intervention. In conclusion, it is important to account for possible non-participation of migrants and travellers. If non-participation is substantial, impact of interventions can be greatly improved by actively approaching these people.

Cluster randomized trials for HIV prevention

PURPOSE OF REVIEW

This paper reviews cluster randomized trials for HIV prevention, focusing on the unique aspects of such trials and describes key cluster randomized trials for HIV prevention from the past decade. Relevant methodological issues are also reviewed.

RECENT FINDINGS

Three cluster randomized trials evaluating sexually transmitted infection control as an HIV prevention tool have given mixed results. Recent modeling studies suggest that the differences are due to differences in the underlying populations rather than design differences. Two trials have shown reduced HIV incidence in intervention target groups without showing a community-wide effect. Areas of active methodological research include ensuring baseline comparability between arms in cluster randomized trials with relatively few clusters, and measuring incidence when the intervention may require time to be fully effective. Innovative approaches to measuring incidence based on so-called 'detuned assays' may be relevant to this problem.

SUMMARY

Cluster randomized trials are qualitatively different from individually randomized trials. As the intervention population may differ from the assessment population, cluster randomized trials of infectious diseases can estimate both direct and indirect intervention effects. Most cluster randomized trial interventions involve behavioral or social components, so the generalizability of results to other settings is often difficult. Modeling studies can aid in the interpretation of results.

Separation of spouses due to travel and living apart raises HIV risk in Tanzanian couples

BACKGROUND

Persons with absent partners may be more vulnerable to risky sexual behavior and therefore HIV. Partner absence can be due to traveling (e.g., family visits or funerals) or to living apart (e.g., work-related or in polygamous marriages). We investigated to what extent partner absence leads to more risky sexual behavior in Tanzanian couples.

METHODS

We compared 95 men and 85 women living apart with 283 men and 331 women living together. Only persons who were still married were included, either living apart or cohabiting at the time of the interview. Subjects were classified into 4 groups: coresidents being either nonmobile or mobile, and people living apart either frequently or infrequently seeing each other.

RESULTS

Most people living apart were polygamously married. Men living apart did not report more extramarital sex than coresident men. However, among coresident men, extramarital sex was reported by 35% of those being mobile compared with 15% of those nonmobile. Among women, those living apart reported extramarital sex more often than coresidents (14% vs. 7%), and this was mainly due to women living apart who infrequently saw their husbands.

CONCLUSIONS

Risky sexual behavior occurs more often in mobile coresident men, and in women living apart infrequently seeing their spouses. These groups are relatively easy to identify and need extra attention in HIV prevention campaigns.

Measuring the public-health impact of candidate HIV vaccines as part of the licensing process

The full impact of vaccines against infectious diseases is manifest at both the individual and the community levels. We argue that evaluating the community-level impact of HIV vaccine candidates should be an integral part of the licensing process. We describe a framework for the public-health evaluation of an HIV vaccine, which is based on the interactive use of mathematical models and community randomised clinical trials (C-RCTs) following completion of individual-based clinical trials (I-RCTs). Mathematical models of HIV vaccine can be used to take public-health considerations into account during the licensing process and can also help to select promising vaccine candidates for testing in C-RCTs. We also describe community and individual-based measures useful for defining public-health criteria necessary to guide the licensing process. To move forward, it is crucial to reach a consensus on what should constitute adequate public-health criteria. At the very least, a suitable vaccine would provide some individual benefit to vaccinees and not be detrimental to the population at large. In future I-RCTs and C-RCTs, quantifying each protective vaccine characteristic (eg, reductions in susceptibility or viral load) is important if regulators are to evaluate adequately the potential community-level impact of the vaccine across different settings, populations, and conditions of use.

Identification of novel risks for nonulcerative sexually transmitted infections among young men in Kisumu, Kenya

OBJECTIVES

STI prevention interventions often aim to reduce HIV incidence. Understanding STI risks may lead to more effective HIV prevention.

GOAL

To identify STI risks among men aged 18-24 in Kisumu, Kenya.

STUDY DESIGN

We analyzed baseline data from a randomized trial of male circumcision. Participants were interviewed for sociodemographic and behavioral risks. Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) were diagnosed by polymerase chain reaction assay and Trichomonas vaginalis (TV) by culture. The outcome for logistic regression analysis was infection with NG, CT, or TV.

RESULTS

Among 2743 men, 214 (7.8%; 95% CI: 6.8%-8.8%) were infected with any STI. In multivariable analysis, statistically significant risks for infection were: living one's whole life in Kisumu (OR = 1.50; 95% CI: 1.12-2.01), preferring "dry" sex (OR = 1.47; 95% CI: 1.05-2.07), HSV-2 seropositivity (OR = 1.37; 95% CI: 1.01-1.86), and inability to ejaculate during sex (OR = 2.04; 95% CI: 1.15-3.62). Risk decreased with increasing age and education, and cleaning one's penis less than 1 hour after sex (OR = 0.51; 95% CI: 0.33-0.80).

CONCLUSION

Understanding how postcoital cleaning, "dry" sex, and sexual dysfunction relate to STI acquisition may improve STI and HIV prevention.

Human immunodeficiency virus (HIV) in developing countries

The human immunodeficiency virus (HIV) is causing the most destructive epidemic of recent times, having been responsible for the deaths of more than 25 million people since it was first recognised in 1981. This global epidemic remains out of control, with reported figures for 2005 of 40 million people infected with HIV. During 2005 there were 4.9 million new infections, showing that transmission is not being prevented, and there were 3.1 million deaths from the acquired immunodeficiency syndrome (AIDS), reflecting the lack of a definitive cure and the limited access to suppressive antiretroviral treatment in the developing countries that are most severely affected. The current state of the epidemic and the response to date are here reviewed. Present and future opportunities for prevention, treatment and surveillance are discussed, with particular reference to progress towards an HIV vaccine, the expansion of the provision of highly active antiretroviral therapy, and the need to focus control programmes on HIV as an infectious disease, rather than as a development issue.

Differences in HIV risk behaviors by gender in a sample of Tanzanian injection drug users

This study investigated differences in drug use and sexual behaviors among from 237 male and 123 female heroin users in Dar es Salaam, Tanzania. Multivariate models of risk of needle sharing were estimated using multivariate logistic regression. Men were significantly older, more likely to inject only white heroin, share needles, and give or lend used needles to other injectors. Women were more likely to be living on the streets, have injected brown heroin, have had sex, have had a higher number of sex partners, and have used a condom with the most recent sex partner. Being male and earning less than US $46 in the past month were significant predictors of increased risk of needle sharing. Despite differences in sociodemographic, drug use, and sexual behaviors by gender, both male and female injectors in Dar es Salaam exhibit elevated risk of HIV infection associated with drug use.

Who uses condoms with whom? Evidence from national probability sample surveys

OBJECTIVES

To explore the changing pattern of condom use from 1990 to 2000; to identify sociodemographic and behavioural factors associated with condom use; and reasons for condom use in 2000.

METHODS

Large probability sample surveys administered among those resident in Britain aged 16-44 (n = 13 765 in 1990, n = 11 161 in 2000). Face to face interviews with self completion components collected sociodemographic, behavioural, and attitudinal data.

RESULTS

Condom use in the past year among sexually active 16-24 year old men increased from 61.0% in 1990 to 82.1% in 2000 (p<0.0001), and from 42.0% to 63.2% (p<0.0001) among women of the same age, with smaller increases among older age groups. Among individuals reporting at least two partners in the previous 4 week period, approximately two thirds reported inconsistent or no condom use (63.1% (95% CI 55.9% to 69.8%) of the men and 68.5% (95% CI 57.6% to 77.7%) of the women).

CONCLUSIONS

Rates of condom use increased substantially between 1990 and 2000, particularly among young people. However, inconsistent condom use by individuals with high rates of partner acquisition may contribute significantly to the recent resurgence in STIs. This group is an important target for intensive and specific sexual health interventions.

Empirical Observations Underestimate the Proportion of Human Immunodeficiency Virus Infections Attributable to Sexually Transmitted Diseases in the Mwanza and Rakai Sexually Transmitted Disease Treatment Trials: Simulation Results

BACKGROUND AND OBJECTIVES

Population attributable fractions (PAF) from observational studies may under- or overestimate the contribution of cofactor sexually transmitted disease (STD) to human immunodeficiency virus (HIV) spread. Empirical PAF estimates from the Mwanza and Rakai trials indicated the proportion of HIV infections attributable to STDs was higher in Mwanza than Rakai.

GOAL OF THIS STUDY

Estimate the "true" proportion (PAFM) of HIV infections attributable to STDs in the Mwanza and Rakai STD trial populations and explore how the evaluated interventions prevented HIV infections.

STUDY DESIGN

The STDSIM model was used to simulate the 2 populations at the baseline of the trials (with no STD treatment interventions) and counterfactual scenarios in which STD cofactor effects on HIV spread were removed either at the start of the trials or 2, 10, and 20 years into the HIV epidemics. Similar methods were used to quantify the contribution of the cure of each STD to overall HIV impact in each site.

RESULTS

: In Mwanza, the highest PAFM for the effect of any single STD over the 2 years of the trial was due to chancroid (40%). The PAFM for all curable STD was 65%. In Rakai, herpes simplex virus type 2 (HSV-2) was the most important STD (PAFM = 23%); the PAFM for curable STD was 20%. In both sites, the proportion of new infections due to treatable STD decreased over time. The decrease was greater for Rakai, where a behavioral risk reduction that preceded the trial reduced STD prevalence. In both sites, the importance of HSV-2 increased later in the HIV epidemics and STD increased transmission of HIV more than acquisition of HIV. In the Mwanza trial, treatment of chancroid contributed most to preventing new HIV infections.

CONCLUSIONS

PAFs calculated from empirical data underestimated the contribution of STD to HIV spread in the Mwanza and Rakai trial populations because STD effects on HIV transmission (as opposed to acquisition) were not captured in the observationally based studies.

Can population differences explain the contrasting results of the Mwanza, Rakai, and Masaka HIV/sexually transmitted disease intervention trials?: A modeling study

OBJECTIVE

To determine whether population differences can explain the contrasting impacts on HIV observed in the Mwanza trial of sexually transmitted disease (STD) syndromic treatment (ST), the Rakai trial of STD mass treatment (MT), and the Masaka trial of information, education, and communication (IEC) with and without ST as well as to predict the effectiveness of each intervention strategy in each population.

METHODS

Stochastic modeling of the transmission of HIV and 6 STDs was used with parameters fitted to demographic, sexual behavior, and epidemiological data from the trials and general review of STD/HIV biology.

RESULTS

The baseline trial populations could be simulated by assuming higher risk behavior in Uganda compared with Mwanza in the 1980s, followed by reductions in risk behavior in Uganda preceding the trials. In line with trial observations, the projected HIV impacts were larger for the ST intervention in Mwanza than for the MT intervention in Rakai or the IEC and IEC + ST interventions in Masaka. All 4 simulated intervention strategies were more effective in reducing incidence of HIV infection in Mwanza than in either Rakai or Masaka.

CONCLUSIONS

Population differences in sexual behavior, curable STD rates, and HIV epidemic stage can explain most of the contrast in HIV impact observed between the 3 trials. This study supports the hypothesis that STD management is an effective HIV prevention strategy in populations with a high prevalence of curable STDs, particularly in an early HIV epidemic.

Extramarital sex among Nigerian men: polygyny and other risk factors

The AIDS epidemic in Nigeria is generalized, with infection primarily occurring through heterosexual transmission. It is important to understand patterns of sexual behavior to assess their impact on the epidemic and to design appropriate intervention strategies. This study examined risk factors for extramarital sex among Nigerian men, with a particular focus on polygyny and peri- and postpartum abstinence. Data from the 2003 Nigeria Demographic and Health Survey were analyzed for 1153 men and their wives. Eleven percent of men reported extramarital sex in the previous year. Logistic regression models showed that men with 3 or more wives were at the greatest risk for extramarital sex, followed by monogamous men, when compared with men with 2 wives. Other significant predictors included region, religion, wealth, age at sexual debut, and self-perceived risk of HIV infection. Peri- and postpartum abstinence was not significant. Based on these findings, HIV prevention programs should include men with 3 or more wives and those living in the southwest region, in addition to activities targeting men of all ages. Given the heterogeneity within Nigeria, further in-depth studies should be undertaken to explore the relation between number of wives, peri- and postpartum abstinence, and extramarital sex within specific communities.

Efforts to control sexually transmitted infections as a means to limit HIV transmission: what is the evidence?

There is overwhelming and compelling evidence that control efforts for STI have a major role to play in the prevention of HIV transmission. Community-based randomized controlled trials are set as the highest standard of evidence for showing the efficacy of STI interventions to prevent HIV transmission. The negative results of recent randomized controlled trials have cast doubt on the positive findings of the Mwanza study. Deeper analysis of the result of these trials has improved understanding of the role of STI interventions and augmented the wealth of evidence provided by numerous epidemiological and biomedical studies. Apart from the biological impact of effective treatment of curable STIs on HIV transmission, clinical services also support the reduction of HIV-risk behaviors. STI interventions should limit the scale of the impending epidemics in Asia and Eastern Europe, depending on the priority that they are given by governments and major donor agencies.

Developments in STD/HIV Interactions: The Intertwining Epidemics of HIV and HSV-2

Antiviral agents aimed at treating HSV-2 chronically infected individuals have proven to be effective in the prevention of symptomatic genital herpes and the reduction of viral shedding. These agents play a key role in current HIV prevention trials that will assess the role of suppression of HSV-2 infection on the risk for HIV acquisition and transmission. An added clinical benefit of treating HSV-2/HIV-coinfected individuals is the potential survival benefit, as suggested by earlier studies and by the recent findings that HSV-2/HIV dually infected individuals have higher viral loads. The results of the current HSV-2 suppression trials may provide additional tools to fight the global spread of HIV infection. Treatment of HSV-2/HIV dually infected individuals may prove to be a low-cost intervention to improve clinical outcomes and delay the need for antiretroviral therapy.

Determinants of the impact of sexually transmitted infection treatment on prevention of HIV infection: a synthesis of evidence from the Mwanza, Rakai, and Masaka intervention trials

Community-randomized trials in Mwanza, Tanzania, and Rakai and Masaka, Uganda, suggested that population characteristics were an important determinant of the impact of sexually transmitted infection (STI) treatment interventions on incidence of human immunodeficiency virus (HIV) infection. We performed simulation modeling of HIV and STI transmission, which confirmed that the low trial impact in Rakai and Masaka could be explained by low prevalences of curable STI resulting from lower-risk sexual behavior in Uganda. The mature HIV epidemics in Uganda, with most HIV transmission occurring outside core groups with high STI rates, also contributed to the low impact on HIV incidence. Simulated impact on HIV was much greater in Mwanza, although the observed impact was larger than predicted from STI reductions, suggesting that random error also may have played some role. Of proposed alternative explanations, increasing herpetic ulceration due to HIV-related immunosuppression contributed little to the diminishing impact of antibiotic treatment during the Ugandan epidemics. The strategy of STI treatment also was unimportant, since syndromic treatment and annual mass treatment showed similar effectiveness in simulations of each trial population. In conclusion, lower-risk behavior and the mature HIV epidemic explain the limited impact of STI treatment on HIV incidence in Uganda in the 1990s. In populations with high-risk sexual behavior and high STI rates, STIs treatment interventions may contribute substantially to prevention of HIV infection.

Efforts to Control Sexually Transmitted Infections As a Means to Limit HIV Transmission: What Is the Evidence?

There is overwhelming and compelling evidence that control efforts for sexually transmitted infection (STI) have a major role to play in the prevention of HIV transmission. Community-based randomized controlled trials are set as the highest standard of evidence for showing the efficacy of STI interventions to prevent HIV transmission. The negative results of recent randomized controlled trials have cast doubt on the positive findings of the Mwanza study. Deeper analysis of the result of these trials has improved understanding of the role of STI interventions and augmented the wealth of evidence provided by numerous epidemiologic and biomedical studies. Apart from the biologic impact of effective treatment of curable STIs on HIV transmission, clinical services also support the reduction of HIV risk behaviors. STI interventions should limit the scale of the impending epidemics in Asia and Eastern Europe, depending on the priority that they are given by governments and major donor agencies.