Comparing patterns of recent and remote Mycobacterium tuberculosis infection determined using the QuantiFERON-TB Gold Plus assay in a high TB burden setting

One quarter of the world's population is estimated to be infected with Mycobacterium tuberculosis. Identifying recent TB infection (TBI) offers an avenue to targeted TB preventative therapy provision, and prevention to disease progression. However, detecting recent TBI remains challenging. The QuantiFERON-TB Gold Plus assay (QFT-Plus) claims to have improved sensitivity in detecting recent TBI, by the addition of the TB2 antigen tube to the TB1 tube used in previous tests. TB2 detects CD8-mediated interferon gamma response, a potential marker of recent infection. We compared QFT-Plus TB1 and TB2 responses in individuals with recent and remote infection in high-burden settings. The Tuberculosis Reduction through Expanded Antiretroviral Treatment and TB Screening (TREATS) Project followed a cohort of adolescents and young people (AYP) aged 15-24 years in Zambia and South Africa to determine TBI incidence measured by QFT-Plus over 24 months. We categorised individuals with QTF-Plus positive result into recent and remote infection. We compared their TB1 and TB2 responses and the antigen tube differential [TB2-TB1], an indicator of CD8-activity, using logistic regression. At baseline, 3876 AYP, 1852/3876 (47.8%) were QFT-Plus positive whilst 2024/3876 (52.2%) QFT-Plus negative. Of the QFT-Plus baseline positives, 1069/1852 (57.7%) tested positive at both 12 and 24 months-remote infection. Of the QFT-Plus baseline negatives, 274/2024(13.3%) converted within a 12-month period- recent infection. TB1 and TB2 responses were higher in remote than recent infection. In recent infection, TB2 responses were greater than TB1 responses. The mean differential was 0.01 IU/ml in recent and -0.22 IU/ml in remote infection, (p = 0.145). The quantitative QFT-Plus results did not appear to reflect a marked distinction between recent and remote infection. Further analysis of the responses of infected individuals who developed disease is required to determine whether any signal in QFT-Plus results may predict progression to disease.

Prevalence and risk factors of M tuberculosis infection in young people across 14 communities in Zambia and South Africa

BACKGROUND

From 2018-2021 the TB Reduction through Expanded Antiretroviral Treatment and TB Screening (TREATS) project took place in 21 Zambian and South African communities. The TREATS Incidence of TB Infection Cohort Study was conducted in adolescents and young people (AYP), aged 15-24 years in 14 communities. We describe the baseline prevalence and risk factors of Mycobacterium tuberculosis (M. tuberculosis) infection among this cohort and explore the quantitative QFT-Plus interferon gamma (IFN-γ) responses.

METHODS AND FINDINGS

A random sample of approximately 300 AYP per community were recruited and information on TB/HIV risk factors, TB symptoms and social mixing patterns collected. QuantiFERON TB Gold Plus assay (QFT-Plus) was used to detect M. tuberculosis infection, following manufacturer's instructions. Logistic regression was used to determine factors associated with infection. 5577 eligible AYP were invited to participate across both countries, with 4648 enrolled. QFT-Plus results were available for 4529: 2552(Zambia) and 1977(South Africa). Overall, 47.6% (2156/4529) AYP had positive QFT-Plus results, the prevalence of infection in South Africa being twice that in Zambia (64.7% (1280/1977) vs 34.3% (867/2552) p<0.001). Infection was associated with age, household contact with TB and alcohol in Zambia but showed no associations in South Africa. The antigen tube differential (TB2-TB1>0.6 IU/ml) of the assay at baseline showed no evidence of association with recent TB exposure.

CONCLUSION

The high prevalence of infection in AYP warrants urgent action to address TB control, especially in South Africa. Further research is required to delineate antigen tube responses of the QFT-Plus assay more precisely to fully realise the benefit of the additional TB2 tube in high TB/HIV burden settings.

Tuberculosis prevalence after 4 years of population-wide systematic TB symptom screening and universal testing and treatment for HIV in the HPTN 071 (PopART) community-randomised trial in Zambia and South Africa: A cross-sectional survey (TREATS)

BACKGROUND

Tuberculosis (TB) prevalence remains persistently high in many settings, with new or expanded interventions required to achieve substantial reductions. The HIV Prevention Trials Network (HPTN) 071 (PopART) community-randomised trial randomised 14 communities to receive the "PopART" intervention during 2014 to 2017 (7 arm A and 7 arm B communities) and 7 communities to receive standard-of-care (arm C). The intervention was delivered door-to-door by community HIV care providers (CHiPs) and included universal HIV testing, facilitated linkage to HIV care at government health clinics, and systematic TB symptom screening. The Tuberculosis Reduction through Expanded Anti-retroviral Treatment and Screening (TREATS) study aimed to measure the impact of delivering the PopART intervention on TB outcomes, in communities with high HIV and TB prevalence.

METHODS AND FINDINGS

The study population of the HPTN 071 (PopART) trial included individuals aged ≥15 years living in 21 urban and peri-urban communities in Zambia and South Africa, with a total population of approximately 1 million and an adult HIV prevalence of around 15% at the time of the trial. Two sputum samples for TB testing were provided to CHiPs by individuals who reported ≥1 TB suggestive symptom (a cough for ≥2 weeks, unintentional weight loss ≥1.5 kg in the last month, or current night sweats) or that a household member was currently on TB treatment. Antiretroviral therapy (ART) was offered universally at clinics in arm A and according to local guidelines in arms B and C. The TREATS study was conducted in the same 21 communities as the HPTN 071 (PopART) trial between 2017 and 2022, and TB prevalence was a co-primary endpoint of the TREATS study. The primary comparison was between the PopART intervention (arms A and B combined) and the standard-of-care (arm C). During 2019 to 2021, a TB prevalence survey was conducted among randomly selected individuals aged ≥15 years (approximately 1,750 per community in arms A and B, approximately 3,500 in arm C). Participants were screened on TB symptoms and chest X-ray, with diagnostic testing using Xpert-Ultra followed by culture for individuals who screened positive. Sputum eligibility was determined by the presence of a cough for ≥2 weeks, or ≥2 of 5 "TB suggestive" symptoms (cough, weight loss for ≥4 weeks, night sweats, chest pain, and fever for ≥2 weeks), or chest X-ray CAD4TBv5 score ≥50, or no available X-ray results. TB prevalence was compared between trial arms using standard methods for cluster-randomised trials, with adjustment for age, sex, and HIV status, and multiple imputation was used for missing data on prevalent TB. Among 83,092 individuals who were eligible for the survey, 49,556 (59.6%) participated, 8,083 (16.3%) screened positive, 90.8% (7,336/8,083) provided 2 sputum samples for Xpert-Ultra testing, and 308 (4.2%) required culture confirmation. Overall, estimated TB prevalence was 0.92% (457/49,556). The geometric means of 7 community-level prevalence estimates were 0.91%, 0.70%, and 0.69% in arms A, B, and C, respectively, with no evidence of a difference comparing arms A and B combined with arm C (adjusted prevalence ratio 1.14, 95% confidence interval, CI [0.67, 1.95], p = 0.60). TB prevalence was higher among people living with HIV than HIV-negative individuals, with an age-sex-community adjusted odds ratio of 2.29 [95% CI 1.54, 3.41] in Zambian communities and 1.61 [95% CI 1.13, 2.30] in South African communities. The primary limitations are that the study was powered to detect only large reductions in TB prevalence in the intervention arm compared with standard-of-care, and the between-community variation in TB prevalence was larger than anticipated.

CONCLUSIONS

There was no evidence that the PopART intervention reduced TB prevalence. Systematic screening for TB that is based on symptom screening alone may not be sufficient to achieve a large reduction in TB prevalence over a period of several years. Including chest X-ray screening alongside TB symptom screening could substantially increase the sensitivity of systematic screening for TB.

TRIAL REGISTRATION

The TREATS study was registered with ClinicalTrials.gov Identifier: NCT03739736 on November 14, 2018. The HPTN 071 (PopART) trial was registered at ClinicalTrials.gov under number NCT01900977 on July 17, 2013.

The impact of a combined TB/HIV intervention on the incidence of TB infection among adolescents and young adults in the HPTN 071 (PopART) trial communities in Zambia and South Africa

BACKGROUND

HPTN071 (PopART) was a cluster randomized trial conducted in Zambian and South African (SA) communities, between 2013-2018. The PopART intervention (universal HIV-testing and treatment (UTT) combined with population-level TB symptom screening) was implemented in 14 communities. The TREATS study (2017-2021) was conducted to evaluate the impact of the PopART intervention on TB outcomes. We report on the impact of the combined TB/HIV intervention on the incidence of TB infection in a cohort of adolescents and young adults (AYA) aged 15-24 years.

METHODS

A random sample of AYA was enrolled between July 2018 and July 2019 in 7 intervention vs 7 standard-of-care communities. We collected questionnaire data on risk factors for TB, and blood for measuring TB infection using QuantiFERON (QFT) Plus. AYA were seen at months 12 and 24 with all procedures repeated. Primary outcome was incidence of TB infection comparing intervention and standard-of-care communities. An incident case was defined as a participant with QFT interferon-gamma response of < 0.2 IU/ml plasma ('negative') at baseline and a QFT interferon-gamma response of > = 0.7 IU/ml ('positive') at follow up.

RESULTS

We enrolled 4,648 AYA, 2,223 (47.8%) had a negative QFT-plus result at baseline, 1,902 (85.6%) had a follow up blood sample taken at 12 months or 24 months. Among the 1,902 AYA, followed for 2,987 person-years, 213 had incident TB infection giving (7.1 per 100 person-years). TB infection incidence rates were 8.7 per 100 person-years in intervention communities compared to 6.0 per 100 person-years in standard-of-care communities. There was no evidence the intervention reduced the transmission of TB (incidence-rate-ratio of 1.45, 95%CI 0.97-2.15, p = 0.063).

CONCLUSION

In our trial setting, we found no evidence that UTT combined with TB active case finding reduced the incidence of TB infection at population level. Our data will inform future modelling work to better understand the population level dynamics of HIV and TB.

Optimising Xpert-Ultra and culture testing to reliably measure tuberculosis prevalence in the community: findings from surveys in Zambia and South Africa

OBJECTIVES

Prevalence surveys remain the best way to assess the national tuberculosis (TB) burden in many countries. Challenges with using culture (the reference standard) for TB diagnosis in prevalence surveys have led to increasing use of molecular tests (Xpert assays), but discordance between these two tests has created problems for deciding which individuals have TB. We aimed to design an accurate diagnostic algorithm for TB prevalence surveys (TBPS) that limits the use of culture.

DESIGN

TBPS in four communities, conducted during 2019.

SETTING

Three Zambian communities and one South-African community included in the TBPS of the Tuberculosis Reduction through Expanded Anti-retroviral Treatment and Screening study.

PARTICIPANTS

Randomly sampled individuals aged ≥15 years. Among those who screened positive on chest X-ray or symptoms, two sputum samples were collected for field Xpert-Ultra testing and a third for laboratory liquid-culture testing. Clinicians reviewed screening and test results; in Zambia, participants with Mycobacterium tuberculosis-positive results were followed up 6-13 months later. Among 10 984 participants, 2092 screened positive, 1852 provided two samples for Xpert-Ultra testing, and 1009 had valid culture results.

OUTCOMES

Culture and Xpert-Ultra test results.

RESULTS

Among 946 culture-negative individuals, 917 were Xpert-negative, 12 Xpert-trace-positive and 17 Xpert-positive (grade very low, low, medium or high), with Xpert categorised as the highest grade of the two sample results. Among 63 culture-positive individuals, 8 were Xpert-negative, 9 Xpert-trace-positive and 46 Xpert-positive. Counting trace-positive results as positive, the sensitivity of Xpert-Ultra compared with culture was 87% (95% CI 76% to 94%) using two samples compared with 76% (95% CI 64% to 86%) using one. Specificity was 97% when trace-positive results were counted as positive and 98% when trace-positive results were counted as negative. Most Xpert-Ultra-positive/culture-negative discordance was among individuals whose Xpert-positive results were trace-positive or very low grade or they reported previous TB treatment. Among individuals with both Xpert-Ultra results grade low or above, the positive-predictive-value was 90% (27/30); 3/30 were plausibly false-negative culture results.

CONCLUSION

Using Xpert-Ultra as the primary diagnostic test in TBPS, with culture only for confirmatory testing, would identify a high proportion of TB cases while massively reducing survey culture requirements.

TRIAL REGISTRATION NUMBER

NCT03739736.

Development of parallel measures to assess HIV stigma and discrimination among people living with HIV, community members and health workers in the HPTN 071 (PopART) trial in Zambia and South Africa

INTRODUCTION

Integrating standardized measures of HIV stigma and discrimination into research studies of emerging HIV prevention approaches could enhance uptake and retention of these approaches, and care and treatment for people living with HIV (PLHIV), by informing stigma mitigation strategies. We sought to develop a succinct set of measures to capture key domains of stigma for use in research on HIV prevention technologies.

METHODS

From 2013 to 2015, we collected baseline data on HIV stigma from three populations (PLHIV (N = 4053), community members (N = 5782) and health workers (N = 1560)) in 21 study communities in South Africa and Zambia participating in the HPTN 071 (PopART) cluster-randomized trial. Forty questions were adapted from a harmonized set of measures developed in a consultative, global process. Informed by theory and factor analysis, we developed seven scales, with values ranging from 0 to 3, based on a 4-point agreement Likert, and calculated means to assess different aspects of stigma. Higher means reflected more stigma. We developed two measures capturing percentages of PLHIV who reported experiencing any stigma in communities or healthcare settings in the past 12 months. We validated our measures by examining reliability using Cronbach's alpha and comparing the distribution of responses across characteristics previously associated with HIV stigma.

RESULTS

Thirty-five questions ultimately contributed to seven scales and two experience measures. All scales demonstrated acceptable to very good internal consistency. Among PLHIV, a scale captured internalized stigma, and experience measures demonstrated that 22.0% of PLHIV experienced stigma in the community and 7.1% in healthcare settings. Three scales for community members assessed fear and judgement, perceived stigma in the community and perceived stigma in healthcare settings. Similarly, health worker scales assessed fear and judgement, perceived stigma in the community and perceived co-worker stigma in healthcare settings. A higher proportion of community members and health workers reported perceived stigma than the proportion of PLHIV who reported experiences of stigma.

CONCLUSIONS

We developed novel, valid measures that allowed for triangulation of HIV stigma across three populations in a large-scale study. Such comparisons will illuminate how stigma influences and is influenced by programmatic changes to HIV service delivery over time.

Incidence of Tuberculosis Among HIV-Positive Individuals Initiating Antiretroviral Treatment at Higher CD4 Counts in the HPTN 071 (PopART) Trial in South Africa

INTRODUCTION

Antiretroviral treatment (ART) guidelines recommend life-long ART for all HIV-positive individuals. This study evaluated tuberculosis (TB) incidence on ART in a cohort of HIV-positive individuals starting ART regardless of CD4 count in a programmatic setting at 3 clinics included in the HPTN 071 (PopART) trial in South Africa.

METHODS

A retrospective cohort analysis of HIV-positive individuals aged ≥18 years starting ART, between January 2014 and November 2015, was conducted. Follow-up was continued until 30 May 2016 or censored on the date of (1) incident TB, (2) loss to follow-up from HIV care or death, or (3) elective transfer out; whichever occurred first.

RESULTS

The study included 2423 individuals. Median baseline CD4 count was 328 cells/μL (interquartile range 195-468); TB incidence rate was 4.41/100 person-years (95% confidence interval [CI]: 3.62 to 5.39). The adjusted hazard ratio of incident TB was 0.27 (95% CI: 0.12 to 0.62) when comparing individuals with baseline CD4 >500 and ≤500 cells/μL. Among individuals with baseline CD4 count >500 cells/μL, there were no incident TB cases in the first 3 months of follow-up. Adjusted hazard of incident TB was also higher among men (adjusted hazard ratio 2.16; 95% CI: 1.41 to 3.30).

CONCLUSIONS

TB incidence after ART initiation was significantly lower among individuals starting ART at CD4 counts above 500 cells/μL. Scale-up of ART, regardless of CD4 count, has the potential to significantly reduce TB incidence among HIV-positive individuals. However, this needs to be combined with strengthening of other TB prevention strategies that target both HIV-positive and HIV-negative individuals.

Identifying community risk factors for HIV among South African adolescents with mental health problems: a qualitative study of parental perceptions

High risk sexual behaviour, alcohol and drug use, and mental health problems combine to yield high levels of HIV-risk behaviour among adolescents with mental health problems. In South Africa, little research has been conducted on parental perspectives of HIV-risk among this population. We conducted a series of focus group discussions with 28 mothers of adolescents receiving services at two mental health clinics in South Africa to identify, from their perspectives, the key community problems facing their children. Participants indicated that HIV remained a serious threat to their adolescent children's well-being, in addition to substance abuse, early sexual debut, and teenage pregnancy. These social problems were mentioned as external to their household dynamics, and thus seemingly beyond the purview of the parent-adolescent relationship. These data have implications for the design of family-based interventions to ameliorate the factors associated with HIV-risk among youth receiving mental health services.

Does perceived life stress mediate the association between HIV status and alcohol use? Evidence from adults living in Cape Town, South Africa

South Africa has the highest prevalence of HIV in the world. Because living with HIV is stressful and because alcohol consumption is often used to cope with stress, we examined whether stress mediates the association between HIV status and alcohol use among adults residing in South African townships. Field workers approached pedestrians or patrons of informal alcohol-serving venues (i.e., shebeens) and invited their participation in a survey. Of the 1717 participants (98% Black, 34% women, mean age = 31 years), 82% were HIV-negative, 9% were HIV-positive, and 9% did not know their test result. Participants living with HIV reported greater perceived life stress compared to participants whose HIV status was negative or unknown. Perceived stress was associated with an increase in the frequency of alcohol use (drinking days, intoxication, and drinking in shebeens/taverns). Subsequent analyses showed that stress mediated the association between HIV status and alcohol use. These findings indicate that greater frequency of drinking days, perceived intoxication, and drinking at shebeens was associated with elevated stress levels among participants who were HIV positive. Perceived life stress mediates the association between HIV status and alcohol use. Programs to enhance stress management among HIV-positive South Africans may help to reduce alcohol consumption, which may, in turn, lead to reduced rates of HIV transmission.

Impact of HIV testing on sexual health communication in South Africa

OBJECTIVES

The South African government recently launched a national campaign to test 15 million South Africans for HIV by 2011. Little is known about how receipt of HIV testing might influence interpersonal communication. To explore these questions, the authors examined the effects of prior HIV testing on sexual health communication among South Africans.

METHODS

Adults (N=1284; 98% black, 36% women, mean age 31) residing in a South African township completed street-intercept surveys.

RESULTS

Of the 1284 participants, 811 (63%) had been tested for HIV. Among those who had been tested, 77% tested negative, 12% tested positive, and 11% did not know their test result or refused to answer. Compared with those who had not been tested, participants who had been tested for HIV were more likely to communicate with community members about (a) HIV/AIDS, (b) getting tested for HIV, and (c) using condoms. Testing positive for HIV was associated with communication with sexual partners about condom use. Among participants who had been tested for HIV, exploratory analyses revealed that those who had engaged in sexual health communication with community members or sexual partners reported more condom-protected sex than those who had not engaged in sexual health communication.

CONCLUSIONS

HIV testing is associated with sexual health communication among South African community members and sexual partners. Offering HIV testing to all South Africans may increase communication and lead to reductions in sexual risk.

Randomized trial of a community-based alcohol-related HIV risk-reduction intervention for men and women in Cape Town South Africa

BACKGROUND

HIV is devastating southern Africa and alcohol use is closely related to HIV transmission risks.

PURPOSE

The current study tested the efficacy of a brief single-session HIV-alcohol risk-reduction intervention for men and women who drink at informal alcohol serving establishments (i.e., shebeens) in South Africa.

METHODS

A randomized community field trial recruited men (N = 117) and women (N = 236) through outreach and chain referrals. Participants received either: (a) 3-h theory-based behavioral HIV-alcohol risk-reduction intervention that focused on skills training for sexual negotiation and condom use or (b) 1-h HIV-alcohol information/education control group. Participants were followed up for 3 and 6 months post-intervention with 89% retention.

RESULTS

The risk-reduction intervention demonstrated significantly less unprotected intercourse, alcohol use before sex, numbers of sex partners, partners met at drinking establishments and greater condom use relative to the control group. However, intervention effects were moderated by alcohol use; lighter drinkers demonstrated significantly more intervention gains than heavier drinkers in the risk-reduction condition. Intervention effects occurred at 3 months follow-up and dissipated by 6 months.

CONCLUSIONS

A brief HIV risk-reduction intervention reduced sexual-risk behaviors among drinkers in South Africa. However, intervention effects were weakest for those who drink heaviest. Our results provide a basis for establishing HIV prevention in alcohol serving establishments in South Africa. Research is needed to identify multi-level intervention models that can reduce risks among heavier drinkers and sustain behavior changes over time.

HIV/AIDS risks among men and women who drink at informal alcohol serving establishments (Shebeens) in Cape Town, South Africa

HIV/AIDS is devastating southern Africa and the spread of HIV is fueled in some populations by alcohol use. Alcohol serving establishments, such as informal drinking places or shebeens, often serve as high-risk venues for HIV transmission. The current study examined the HIV risks of men (N = 91) and women (N = 248) recruited from four shebeens in a racially integrating township in Cape Town South Africa. Participants completed confidential measures of demographic characteristics, HIV risk history, alcohol and drug use, and HIV risk behaviors. Comparisons of 94 (28%) participants who reported meeting sex partners at shebeens to the remaining sample of shebeen goers, controlling for potential confounds, demonstrated a pattern of higher risk for HIV infection among persons who met sex partners at shebeens. Few differences, however, were observed between men (N = 47) and women (N = 47) who had met sex partners at shebeens, suggesting greater gender similarities than gender differences in this important subpopulation. These results indicate an urgent need for multi-level HIV prevention interventions targeting shebeens and the men and women who drink in these settings.

HIV/AIDS risk reduction counseling for alcohol using sexually transmitted infections clinic patients in Cape Town, South Africa

BACKGROUND

HIV is ravaging southern Africa, and HIV transmission risk behaviors are facilitated by alcohol use in sexual contexts. There are no known interventions that directly target HIV risk behavior among people who drink and are at risk for HIV in Africa.

PURPOSE

To test a behavioral risk reduction counseling intervention for use in sexually transmitted infection (STI) clinics in southern Africa.

METHODS

A randomized intervention trial was conducted with 143 STI clinic patients in Cape Town, South Africa. Participants received an experimental 60-minute HIV and alcohol risk reduction behavioral skills intervention or a control 20-minute HIV education condition. Participants were followed for 3 and 6 months after the intervention, with 73% retention.

RESULTS

Overall, the experimental intervention demonstrated more than a 25% increase in condom use and a 65% reduction in unprotected intercourse over the 6-month follow-up period, with risk reduction significantly greater for the experimental condition than for the control condition at both follow-ups. Alcohol use in sexual contexts [F(1,94) = 6.2; P < 0.05] and expectancies that alcohol enhances sexual experiences [F(1,94) = 8.3; P < 0.01] were also significantly lower for the experimental condition at the 3-month follow-up.

CONCLUSIONS

An HIV prevention counseling intervention reduced HIV transmission risks for up to 6 months in this STI clinic population. Effects may be sustained with structural interventions to reduce alcohol use in sexual contexts and support risk reduction behavior changes over the long-term.