When did HIV incidence peak in Harare, Zimbabwe? Back-calculation from mortality statistics

Can AIDS education reduce HIV stigma? Evidence from Zimbabwe

HIV stigma remains a barrier to HIV prevention, testing, and treatment in sub-Saharan Africa. This study uses Zimbabwe Demographic and Health Survey data to examine how education reduces HIV stigma, focusing on two key initiatives: the 1992 AIDS Action Program, which enhanced HIV awareness, and the 1980 education reform, which expanded schooling access. By addressing gaps in the literature on external HIV stigma, the study highlights education's long-term impact on attitudes toward people living with HIV. Our findings show that the 1980 reform is associated with a 1.19-year increase in educational attainment and a 42.6% rise in secondary school attendance for children aged 2-7 years in 1980 compared to those aged 16 and older. Furthermore, each additional year of schooling after the AIDS Action Program is associated with a 12.1% reduction in the likelihood of stigmatizing people with HIV and a 12.8% increase in HIV knowledge. Stigma reduction is more pronounced among rural residents (13.3%) and women (5.9%) but is insignificant for men and urban dwellers. These results underscore the role of schools in improving public health knowledge and reducing HIV stigma, offering valuable insights for future educational and health strategies.

Economy, migrant labour and sex work: interplay of HIV epidemic drivers in Zimbabwe over three decades

BACKGROUND

HIV took off rapidly in Zimbabwe during the 1980s. Yet, between 1998 and 2003, as the economy faltered, HIV prevalence declined abruptly and without clear explanation.

METHODS

We reviewed epidemiological, behavioural, and economic data over three decades to understand changes in economic conditions, migrant labour and sex work that may account for observed fluctuations in Zimbabwe's HIV epidemic. Potential biases related to changing epidemic paradigms and data sources were examined.

RESULTS

Early studies describe rural poverty, male migrant labour and sex work as conditions facilitating HIV/sexually transmitted infection (STI) transmission. By the mid-1990s, as Zimbabwe's epidemic became more generalized, research focus shifted to general population household surveys. Yet, less than half as many men than women were found at home during surveys in the 1990s, increasing to 80% during the years of economic decline. Other studies suggest that male demand for sex work fell abruptly as migrant workers were laid off, picking up again when the economy rebounded after 2009. Numbers of clients reported by sex workers, and their STI rates, followed similar patterns reaching a nadir in the early 2000s. Studies from 2009 describe a return to more active sex work, linked to increasing client demand, as well as a revitalized programme reaching sex workers.

CONCLUSION

The importance of the downturn in migrant labour and resultant changes in sex work may be underestimated as drivers of Zimbabwe's rapid HIV incidence and prevalence declines. Household surveys underrepresent populations at the highest risk of HIV/STI acquisition and transmission, and these biases vary with changing economic conditions.

Estimating the impact of antiretroviral treatment on adult mortality trends in South Africa: A mathematical modelling study

BACKGROUND

Substantial reductions in adult mortality have been observed in South Africa since the mid-2000s, but there has been no formal evaluation of how much of this decline is attributable to the scale-up of antiretroviral treatment (ART), as previous models have not been calibrated to vital registration data. We developed a deterministic mathematical model to simulate the mortality trends that would have been expected in the absence of ART, and with earlier introduction of ART.

METHODS AND FINDINGS

Model estimates of mortality rates in ART patients were obtained from the International Epidemiology Databases to Evaluate AIDS-Southern Africa (IeDEA-SA) collaboration. The model was calibrated to HIV prevalence data (1997-2013) and mortality data from the South African vital registration system (1997-2014), using a Bayesian approach. In the 1985-2014 period, 2.70 million adult HIV-related deaths occurred in South Africa. Adult HIV deaths peaked at 231,000 per annum in 2006 and declined to 95,000 in 2014, a reduction of 74.7% (95% CI: 73.3%-76.1%) compared to the scenario without ART. However, HIV mortality in 2014 was estimated to be 69% (95% CI: 46%-97%) higher in 2014 (161,000) if the model was calibrated only to HIV prevalence data. In the 2000-2014 period, the South African ART programme is estimated to have reduced the cumulative number of HIV deaths in adults by 1.72 million (95% CI: 1.58 million-1.84 million) and to have saved 6.15 million life years in adults (95% CI: 5.52 million-6.69 million). This compares with a potential saving of 8.80 million (95% CI: 7.90 million-9.59 million) life years that might have been achieved if South Africa had moved swiftly to implement WHO guidelines (2004-2013) and had achieved high levels of ART uptake in HIV-diagnosed individuals from 2004 onwards. The model is limited by its reliance on all-cause mortality data, given the lack of reliable cause-of-death reporting, and also does not allow for changes over time in tuberculosis control programmes and ART effectiveness.

CONCLUSIONS

ART has had a dramatic impact on adult mortality in South Africa, but delays in the rollout of ART, especially in the early stages of the ART programme, have contributed to substantial loss of life. This is the first study to our knowledge to calibrate a model of ART impact to population-level recorded death data in Africa; models that are not calibrated to population-level death data may overestimate HIV-related mortality.

Population-level impact of Zimbabwe's National Behavioural Change Programme

OBJECTIVE

To assess the impact of Zimbabwe's National Behavioural Change Programme (NBCP) on biological and behavioral outcomes.

METHODS

Representative household biobehavioral surveys of 18- to 44-year-olds were conducted in randomly selected enumeration areas in 2007 and 2011 to 2012. We examined program impact on HIV prevalence among young women, nonregular partnerships, condom use with nonregular partners, and HIV testing, distinguishing between highly exposed and low-exposed communities and individuals. We conducted (1) difference-in-differences analyses with communities as unit of analysis and (2) analyses of key outcomes by individual-level program exposure.

RESULTS

Four thousand seven hundred seventy-six people were recruited in 2007 and 10,059 in 2011 to 2012. We found high exposure to NBCP in 2011. Prevalence of HIV and reported risky behaviors declined between 2007 and 2011. Community-level analyses showed a smaller decline in HIV prevalence among young women in highly exposed areas (11.0%-10.1%) than low-exposed areas (16.9%-10.3%, P = 0.078). Among young men, uptake of nonregular partners declined more in highly exposed areas (25%-16.8%) than low-exposed areas (21.9%-20.7%, P = 0.055) and HIV testing increased (27.2%-46.1% vs. 31.0%-34.4%, P = 0.004). Individual-level analyses showed higher reported condom use with nonregular partners among highly exposed young women (53% vs. 21% of unexposed counterparts, P = 0.037).

CONCLUSIONS

We conducted the first impact evaluation of a NBCP and found positive effects of program exposure on key behaviors among certain gender and age groups. HIV prevalence among young women declined but could not be attributed to program exposure. These findings suggest substantial program effects regarding demand creation and justify program expansion.

Modelling HIV incidence and survival from age-specific seroprevalence after antiretroviral treatment scale-up in rural South Africa

OBJECTIVE

Our study uses sex-specific and age-specific HIV prevalence data from an ongoing population-based demographic and HIV survey to infer HIV incidence and survival in rural KwaZulu-Natal between 2003 and 2011, a period when antiretroviral treatment (ART) was rolled out on a large scale.

DESIGN

Catalytic mathematical model for estimating HIV incidence and differential survival in HIV-infected persons on multiple rounds of HIV seroprevalence.

METHODS

We evaluate trends of HIV incidence and survival by estimating parameters separately for women and men aged 15-49 years during three calendar periods (2003-2005, 2006-2008, 2009-2011) reflecting increasing ART coverage. We compare model-based estimates of HIV incidence with observed cohort-based estimates from the longitudinal HIV surveillance.

RESULTS

Median survival after HIV infection increased significantly between 2003-2005 and 2009-2011 from 10.0 [95% confidence interval (CI) 8.8-11.2] to 14.2 (95% CI 12.6-15.8) years in women (P < 0.001) and from 10.0 (95% CI 9.2-10.8) to 14.0 (95% CI 10.6-17.4) years in men (P = 0.02). Our model suggests no statistically significant reduction of HIV incidence in the age-group 15-49 years in 2009-2011 compared with 2003-2005. Age-specific and sex-specific model-based HIV incidence estimates were in good agreement with observed cohort-based estimates from the ongoing HIV surveillance.

CONCLUSION

Our catalytic modelling approach using cross-sectional age-specific HIV prevalence data could be useful to monitor trends of HIV incidence and survival in other African settings with a high ART coverage.

Potential cost-effectiveness of schistosomiasis treatment for reducing HIV transmission in Africa--the case of Zimbabwean women

Background

Epidemiological data from Zimbabwe suggests that genital infection with Schistosoma haematobium may increase the risk of HIV infection in young women. Therefore, the treatment of Schistosoma haematobium with praziquantel could be a potential strategy for reducing HIV infection. Here we assess the potential cost-effectiveness of praziquantel as a novel intervention strategy against HIV infection.

Methods

We developed a mathematical model of female genital schistosomiasis (FGS) and HIV infections in Zimbabwe that we fitted to cross-sectional data of FGS and HIV prevalence of 1999. We validated our epidemic projections using antenatal clinic data on HIV prevalence. We simulated annual praziquantel administration to school-age children. We then used these model predictions to perform a cost-effectiveness analysis of annual administration of praziquantel as a potential measure to reduce the burden of HIV in sub-Saharan Africa.

Findings

We showed that for a variation of efficacy between 30–70% of mass praziquantel administration for reducing the enhanced risk of HIV transmission per sexual act due to FGS, annual administration of praziquantel to school-age children in Zimbabwe could result in net savings of US$16–101 million compared with no mass treatment of schistosomiasis over a ten-year period. For a variation in efficacy between 30–70% of mass praziquantel administration for reducing the acquisition of FGS, annual administration of praziquantel to school-age children could result in net savings of US$36−92 million over a ten-year period.

Conclusions

In addition to reducing schistosomiasis burden, mass praziquantel administration may be a highly cost-effective way of reducing HIV infections in sub-Saharan Africa. Program costs per case of HIV averted are similar to, and under some conditions much better than, other interventions that are currently implemented in Africa to reduce HIV transmission. As a cost-saving strategy, mass praziquantel administration should be prioritized over other less cost-effective public health interventions.

Evidence from epidemiological and clinical studies supports the hypothesis that genital infection with Schistosoma haematobium increases the risk of becoming infected with HIV among women in sub-Saharan Africa. Praziquantel is an oral, nontoxic, inexpensive medication recommended for treatment of schistosomiasis, which might be able to prevent the development of genital schistosomiasis. We constructed a mathematical model of female genital schistosomiasis and HIV infections, which we calibrated using epidemiological data from Zimbabwe. We used this model to investigate the potential cost-effectiveness of mass drug administration with praziquantel as an intervention strategy for reducing HIV transmission in sub-Saharan Africa. We showed that mass drug administration with praziquantel may be a timely, innovative, and cost-saving intervention strategy for HIV prevention in sub-Saharan Africa. As a cost-saving strategy, mass drug administration with praziquantel should be prioritized over other less cost-effective public health interventions. Our findings indicate the possible benefit of scaling up schistosomiasis control efforts in sub-Saharan Africa, and especially in areas were Schistosoma haematobium and HIV are highly prevalent.

Human immunodeficiency virus prevalence, incidence, and residual transmission risk in first-time and repeat blood donations in Zimbabwe: implications on blood safety

BACKGROUND

National Blood Service Zimbabwe human immunodeficiency virus (HIV) risk management strategy includes screening and discarding of first-time donations, which are collected in blood packs without an anticoagulant (dry pack). To evaluate the impact of discarding first-time donations on blood safety the HIV prevalence, incidence, and residual risk in first-time and repeat donations (wet packs) were compared.

STUDY DESIGN AND METHODS

Donor data from 2002 to 2010 were retrieved from a centralized national electronic donor database and retrospectively analyzed. Chi-square test was used to compare HIV prevalence with relative risk (RR), and the RR point estimates and 95% confidence interval (CI) are reported. Trend analysis was done using Cochran-Armitage trend test. HIV residual risk estimates were determined using published residual risk estimation models.

RESULTS

Over the 9 years the overall HIV prevalence estimates are 1.29% (n = 116,058) and 0.42% (n = 434,695) for first-time and repeat donations, respectively. The overall RR was 3.1 (95% CI, 2.9-3.3; p < 0.0001). The overall mean residual transmission risk of HIV window phase donations in first-time was 1:7384 (range, 1:11,308-1:5356) and in repeat donors it was 1:5496 (range, 1:9943-1:3347).

CONCLUSION

The significantly high HIV prevalence estimates recorded in first-time over repeat donations is indicative of the effectiveness of the HIV risk management strategy. However, comparable residual transmission risk estimates in first-time and repeat donors point to the need to further review the risk management strategies. Given the potential wastage of valuable resources, future studies should focus on the cost-effectiveness and utility of screening and discarding first-time donations.

Adult mortality in the cities of Bulawayo and Harare, Zimbabwe: 1979-2008

Background

Zimbabwe has been severely affected by the HIV/AIDS and tuberculosis epidemics, with an estimated 80% of tuberculosis patients being HIV infected. We set out to use annual population-mortality records from the cities of Harare and Bulawayo to describe trends and possible causes of mortality from 1979 to 2008. The specific objectives were to document overall, sex and age-specific mortality, proportion of deaths attributed to AIDS and tuberculosis, and changes in death rates since the start of antiretroviral therapy in 2004.

Methods

This retrospective descriptive study used existing mortality records of the Health Services departments in Harare and Bulawayo. Data points included: estimated yearly total population; groupings by sex and age; deaths (total and by sex and age groups for each year of the study period); and most frequently reported causes of death (for age groups <15 years, 15-44 years and ≥45 years). Data on deaths were aggregated by year, and crude, sex- and age-specific death rates were calculated per 1000 population. Tuberculosis and HIV-related disease-specific death rates and proportion of deaths attributed to these conditions were computed.

Results

In both cities, crude death rates were lowest in the late 1980s, increased three- to five-fold by the early 2000s, and began a slow and, in the case of Bulawayo, intermittent decline from 2004. Sex-specific death rates followed a similar trend, being higher in males than in females. The death rates in the age groups <5 years, 15-44 years and ≥45 years showed significant increases, with a gradual levelling off and decline from 2002 onwards; death rates in those aged 5-14 years were relatively unaffected. Tuberculosis and HIV caused 70% of deaths in the age group of 15-44 years from the early 1990s.

Conclusions

This study used routinely collected population-mortality data that are rare in resource-limited settings, and it described, for the first time in Zimbabwe, the effects of the HIV/AIDS epidemic and the introduction of antiretroviral therapy on death rates in two large cities. After a substantial rise in crude mortality rates, there has been a decline associated with the introduction of ART. Such routine population data must continue to be collected, collated and analyzed.

Declining HIV prevalence and incidence in perinatal women in Harare, Zimbabwe

BACKGROUND

In several recent papers it has been suggested that HIV prevalence and incidence are declining in Zimbabwe as a result of changing sexual behavior. We provide further support for these suggestions, based on an analysis of more extensive, age-stratified, HIV prevalence data from 1990 to 2009 for perinatal women in Harare, as well as data on incidence and mortality.

METHODOLOGY/PRINCIPAL FINDINGS

Pooled prevalence, incidence and mortality were fitted using a simple susceptible-infected (SI) model of HIV transmission; age-stratified prevalence data were fitted using double-logistic functions. We estimate that incidence peaked at 5.5% per year in 1991 declining to 1% per year in 2010. Prevalence peaked in 1998/9 [35.9% (CI95: 31.3-40.7)] and decreased by 67% to 11.9% (CI95: 10.1-13.8) in 2009. For women <20y, 20-24y, 25-29y, 30-34y and ≥35y, prevalence peaked at 25.4%, 34.2%, 47.1%, 44.0% and 33.5% in 1993, 1996, 1997, 1998 and 1999, respectively, declining thereafter in every age group. Among women <25y, prevalence peaked in 1994 at 28.8% declining thereafter by 69% to 8.9% (CI95: 6.8-11.5) in 2009.

CONCLUSION/SIGNIFICANCE

HIV prevalence declined substantially among perinatal women in Harare after 1998 consequent upon a decline in incidence starting in the early 1990s. Our model suggests that this was primarily a result of changes in behavior which we attribute to a general increase in awareness of the dangers of AIDS and the ever more apparent increases in mortality.

Political and socio-economic instability: does it have a role in the HIV/AIDS epidemic in sub-Saharan Africa?

Many sub-Saharan African countries are confronted by the HIV/AIDS epidemic. This article reviews academic literature in the social sciences and health to discover why HIV/AIDS has become an epidemic in sub-Saharan Africa and not in other parts of the world. This was studied by examining the social determinants of diminishment of tradition and social cohesion in terms of political, social and economic problems. Four countries in this region were selected for this case study, namely South Africa, Botswana, Uganda and Zimbabwe. The findings showed that instability in socio-economic and political aspects in these nations was responsible for creating a suitable environment for the spread of HIV/AIDS infection. This paper concludes by using the theories of collective action/responsibility and social cohesion to hypothesise that the breakdown of social ties due to various kinds of conflicts and unrest is one of the main contributors to the HIV/AIDS epidemic.

The incidence of HIV among women recruited during late pregnancy and followed up for six years after childbirth in Zimbabwe

Background

HIV incidence is a useful tool for improving the targeting of populations for interventions and assessing the effectiveness of prevention strategies. A study in Harare, Zimbabwe reported cumulative incidences of 3.4% (3.0-3.8) and 6.5% (5.7-7.4) among post-partum women followed for 12 and 24 months respectively between 1997 and 2001. According to a Government report on HIV the prevalence of HIV fell from about 30% in 1999 to 14% in 2008. The purpose of this study was to determine the incidence of HIV-1 among women enrolled during late pregnancy and followed for six years after childbirth and to identify risk factors associated with acquisition of HIV.

Methods

HIV-uninfected pregnant women around 36 weeks gestation were enrolled from primary health care clinics in peri-urban settlements around Harare and followed-up for up to six years after childbirth. At every visit a questionnaire was interview-administered to obtain socio-demographic data and sexual history since the previous visit. A genital examination was performed followed by the collection of biological samples.

Results

Of the 552 HIV-uninfected women 444 (80.4%) were seen at least twice during the six years follow-up and 39 acquired HIV, resulting in an incidence (95% CI) of 2.3/100 woman-years-at-risk (wyar) (1.1-4.1). The incidence over the first nine months post-partum was 5.7/100 wyar (3.3-8.1). A greater proportion of teenagers (15.3%) contributed to a high incidence rate of 2.9/100 (0.6-8.7) wyar. In multivariate analysis lower education of participant, RR 2.1 (1.1-4.3) remained significantly associated with HIV acquisition. Other risk factors associated with acquisition of HIV-1 in univariate analysis were young age at sexual debut, RR 2.3, (1.0-5.6) and having children with different fathers, RR 2.7(1.3-5.8). Women that knew that their partners had other sexual partners were about four times more likely to acquire HIV, RR 3.8 (1.3-11.2).

Conclusion

The incidence of HIV was high during the first nine months after childbirth. Time of seroconversion, age and educational level of seroconverter are important factors that must be considered when designing HIV intervention strategies.

HIV decline in Zimbabwe due to reductions in risky sex? Evidence from a comprehensive epidemiological review

BACKGROUND

Recent data from antenatal clinic (ANC) surveillance and general population surveys suggest substantial declines in human immunodeficiency virus (HIV) prevalence in Zimbabwe. We assessed the contributions of rising mortality, falling HIV incidence and sexual behaviour change to the decline in HIV prevalence.

METHODS

Comprehensive review and secondary analysis of national and local sources on trends in HIV prevalence, HIV incidence, mortality and sexual behaviour covering the period 1985-2007.

RESULTS

HIV prevalence fell in Zimbabwe over the past decade (national estimates: from 29.3% in 1997 to 15.6% in 2007). National census and survey estimates, vital registration data from Harare and Bulawayo, and prospective local population survey data from eastern Zimbabwe showed substantial rises in mortality during the 1990s levelling off after 2000. Direct estimates of HIV incidence in male factory workers and women attending pre- and post-natal clinics, trends in HIV prevalence in 15-24-year-olds, and back-calculation estimates based on the vital registration data from Harare indicated that HIV incidence may have peaked in the early 1990s and fallen during the 1990s. Household survey data showed reductions in numbers reporting casual partners from the late 1990s and high condom use in non-regular partnerships between 1998 and 2007.

CONCLUSIONS

These findings provide the first convincing evidence of an HIV decline accelerated by changes in sexual behaviour in a southern African country. However, in 2007, one in every seven adults in Zimbabwe was still infected with a life-threatening virus and mortality rates remained at crisis level.

Evolution and molecular epidemiology of subtype C HIV-1 in Zimbabwe

OBJECTIVE

To investigate the origins and evolutionary history of subtype C HIV-1 in Zimbabwe in a context of regional conflict and migration.

DESIGN

HIV-1C pol sequence datasets were generated from four sequential cohorts of antenatal women in Harare, Zimbabwe sampled over 15 years (1991-2006).

METHODS

One hundred and seventy-seven HIV-1C pol sequences were obtained from four successive cohorts in Zimbabwe. Maximum-likelihood methods were used to explore phylogenetic relationships between Zimbabwean HIV-1C sequences and subtype C strains from other regions. A Bayesian coalescent-based framework was used to estimate evolutionary parameters for HIV-1C in Zimbabwe, including origin and demographic growth patterns.

RESULTS

Zimbabwe HIV-1C pol demonstrated increasing sequence divergence over the 15-year period. Nearly all Zimbabwe sequences clustered phylogenetically with subtype C strains from neighboring countries. Bayesian evolutionary analysis indicated a most recent common ancestor date of 1973 with three epidemic growth phases: an initial, slow phase (1970s) followed by exponential growth (1980s), and a linearly expanding epidemic to the present. Bayesian trees provided evidence for multiple HIV-1C introductions into Zimbabwe during 1979-1981, corresponding with Zimbabwean national independence following a period of socio-political instability.

CONCLUSION

The Zimbabwean HIV-1C epidemic likely originated from multiple introductions in the late 1970s and grew exponentially during the 1980s, corresponding to changing political boundaries and rapid population influx from neighboring countries. The timing and phylogenetic clustering of the Zimbabwean sequences is consistent with an origin in southern Africa and subsequent expansion. HIV-1 sequence data contain important epidemiological information, which can help focus treatment and prevention strategies in light of more recent political volatility in Zimbabwe.

Assessing evidence for behaviour change affecting the course of HIV epidemics: a new mathematical modelling approach and application to data from Zimbabwe

BACKGROUND

Determining whether interventions to reduce HIV transmission have worked is essential, but complicated by the potential for generalised epidemics to evolve over time without individuals changing risk behaviour. We aimed to develop a method to evaluate evidence for changes in risk behaviour altering the course of an HIV epidemic.

METHODS

We developed a mathematical model of HIV transmission, incorporating the potential for natural changes in the epidemic as it matures and the introduction of antiretroviral treatment, and applied a Bayesian Melding framework, in which the model and observed trends in prevalence can be compared. We applied the model to Zimbabwe, using HIV prevalence estimates from antenatal clinic surveillance and house-hold based surveys, and basing model parameters on data from sexual behaviour surveys.

RESULTS

There was strong evidence for reductions in risk behaviour stemming HIV transmission. We estimate these changes occurred between 1999 and 2004 and averted 660,000 (95% credible interval: 460,000-860,000) infections by 2008.

DISCUSSION

The model and associated analysis framework provide a robust way to evaluate the evidence for changes in risk behaviour affecting the course of HIV epidemics, avoiding confounding by the natural evolution of HIV epidemics.