Do HIV prevalence trends in antenatal clinic surveillance represent trends in the general population in the antiretroviral therapy era? The case of Manicaland, East Zimbabwe

HIV burden and the global fast-track targets progress among pregnant women in Tanzania calls for intensified case finding: Analysis of 2020 antenatal clinics HIV sentinel site surveillance

BACKGROUND

For successful HIV response, updated information on the burden and progress toward HIV elimination targets are required to guide programmatic interventions. We used data from the 2020 HIV sentinel surveillance to update on the burden and factors associated with HIV infection, HIV status awareness, and ART coverage among pregnant women in Tanzania mainland.

METHODOLOGY

We conducted the surveillance in 159 antenatal clinics (ANC) from all 26 regions of Tanzania's mainland from September to December 2020. This cross-sectional study included all pregnant women (≥15 years) on their first ANC visit in the current pregnancy during the survey period. Routine HIV counselling and testing were done at the facility. A multivariable logistic regression model accounting for the survey design was used to examine factors associated with HIV infections.

RESULTS

38,783 pregnant women were enrolled (median age (IQR) = 25 (21-30) years). HIV prevalence was 5.9% (95%CI: 5.3% - 6.6%), ranging from 1.9% in the Manyara region to 16.4% in the Njombe region. Older age, lower and no education, not being in a marital union, and living in urban or semi-urban areas were associated with higher odds of HIV infection. HIV status awareness among women who tested positive was 70.9% (95% CI: 67.5%- 74.0%). ART coverage among those aware of their status was 91.6% (86.5%- 94.9%). Overall, 66.6% (95% CI: 62.4%- 70.6%) of all pregnant women who tested positive for HIV knew their HIV status and were on ART.

CONCLUSION

HIV is increasingly prevalent among pregnant women in Tanzania mainland especially among older, those with lower or no formal education, those outside marital union, and pregnant women living in urban and semi-urban areas. Behind the global fast-target to end HIV/ AIDS, about a third of pregnant women living with HIV initiating ANC were not on ART. Interventions to increase HIV testing and linkage to care among women of reproductive age should be intensified.

Effect of HIV Infection and Antiretroviral Treatment on Pregnancy Rates in the Western Cape Province of South Africa

BACKGROUND

Previous studies suggest that untreated human immunodeficiency virus (HIV) infection is associated with a reduced incidence of pregnancy, but studies of the effect of antiretroviral treatment (ART) on pregnancy incidence have been inconsistent.

METHODS

Routine data from health services in the Western Cape province of South Africa were linked to identify pregnancies during 2007-2017 and maternal HIV records. The time from the first (index) pregnancy outcome date to the next pregnancy was modeled using Cox proportional hazards models.

RESULTS

During 2007-2017, 1 042 647 pregnancies were recorded. In all age groups, pregnancy incidence rates were highest in women who had started ART, lower in HIV-negative women, and lowest in ART-naive HIV-positive women. In multivariable analysis, after controlling for the most recent CD4+ T-cell count, pregnancy incidence rates in HIV-positive women receiving ART were higher than those in untreated HIV-positive women (adjusted hazard ratio, 1.63; 95% confidence interval, 1.59-1.67) and those in HIV-negative women.

CONCLUSION

Among women who have recently been pregnant, receipt of ART is associated with high rates of second pregnancy. Better integration of family planning into HIV care services is needed.

Combining national survey with facility-based HIV testing data to obtain more accurate estimate of HIV prevalence in districts in Uganda

Background

National or regional population-based HIV prevalence surveys have small sample sizes at district or sub-district levels; this leads to wide confidence intervals when estimating HIV prevalence at district level for programme monitoring and decision making. Health facility programme data, collected during service delivery is widely available, but since people self-select for HIV testing, HIV prevalence estimates based on it, is subject to selection bias. We present a statistical annealing technique, Hybrid Prevalence Estimation (HPE), that combines a small population-based survey sample with a facility-based sample to generate district level HIV prevalence estimates with associated confidence intervals.

Methods

We apply the HPE methodology to combine the 2011 Uganda AIDS indicator survey with the 2011 health facility HIV testing data to obtain HIV prevalence estimates for districts in Uganda. Multilevel logistic regression was used to obtain the propensity of testing for HIV in a health facility, and the propensity to test was used to combine the population survey and health facility HIV testing data to obtain the HPEs. We assessed comparability of the HPEs and survey-based estimates using Bland Altman analysis.

Results

The estimates ranged from 0.012 to 0.178 and had narrower confidence intervals compared to survey-based estimates. The average difference between HPEs and population survey estimates was 0.00 (95% CI: − 0.04, 0.04). The HPE standard errors were 28.9% (95% CI: 23.4–34.4) reduced, compared to survey-based standard errors. Overall reduction in HPE standard errors compared survey-based standard errors ranged from 5.4 to 95%.

Conclusions

Facility data can be combined with population survey data to obtain more accurate HIV prevalence estimates for geographical areas with small population survey sample sizes. We recommend use of the methodology by district level managers to obtain more accurate HIV prevalence estimates to guide decision making without incurring additional data collection costs.

Difference in HIV prevalence by testing venue: results from population level survey in Uganda

While countries now have national and regional measures of HIV prevalence, sub-regional (district) and sub-district level information is sparse. Growing demand to fill this gap with health facility testing data, in addition to other HIV testing data requires understanding the comparability of these various data sources. We analysed the 2011 Uganda AIDS indicator survey (UAIS) data to assess the proportion of people tested for HIV across Uganda and the venue of testing. We compared HIV prevalence between those tested in a health facility and those testing in a community setting and investigated factors associated with HIV positivity in each subgroup.

We computed HIV prevalence among those tested in a health facility and community setting and obtained HIV prevalence ratio and 95% confidence intervals using the Katz et al (1978) methodology. Factors associated with HIV positivity in each subgroup were assessed using multilevel logistic regression.

Of the 11, 685 individuals, 8,978 (77.1%) had ever tested for HIV in a health facility (female: 6,396, 84.0% versus male: 2,582, 64.2%). Fifty nine percent tested in a health facility in the 12 months preceding the survey (female: 5,507, 72.7% versus male: 1,413, 34.9%). HIV prevalence ratio was1.8 times among those tested in a health facility compared to those tested at community setting (10.9% [95% CI: 10.0-11.7] versus 6.2% [95% CI: 5.4-7.0]). Among heath facility testers, older age group, previously married and having no sexual partner was associated with significantly higher HIV prevalence.

Using facility testing data for program planning and implementation should take into consideration the elevated and varying HIV prevalence among individuals accessing HIV testing services at health facilities as well as differences in their social demographic characteristics.

Targeting Pregnant Women for Malaria Surveillance

Women attending antenatal care (ANC) are a generally healthy, easy-access population, contributing valuable data for infectious disease surveillance at the community level. ANC-based malaria surveillance would provide a routine measure of the malaria burden in pregnancy, which countries lack, whilst potentially improving pregnancy outcomes. It could also offer contemporary information on temporal trends and the geographic distribution of malaria burden as well as intervention coverage in the population to guide resource allocation and to assess progress towards elimination. Here, we review the factors underlying the relationship between Plasmodium falciparum in pregnancy and in the community, and outline strengths and limitations of an ANC-based surveillance in sub-Saharan Africa, its potential role within wider malaria surveillance systems, and subsequent programmatic applications.

Using ante-natal clinic prevalence data to monitor temporal changes in malaria incidence in a humanitarian setting in the Democratic Republic of Congo

BACKGROUND

The number of clinical cases of malaria is often recorded in resource constrained or conflict settings as a proxy for disease burden. Interpreting case count data in areas of humanitarian need is challenging due to uncertainties in population size caused by security concerns, resource constraints and population movement. Malaria prevalence in women visiting ante-natal care (ANC) clinics has the potential to be an easier and more accurate metric for malaria surveillance that is unbiased by population size if malaria testing is routinely conducted irrespective of symptoms.

METHODS

A suite of distributed lag non-linear models was fitted to clinical incidence time-series data in children under 5 years and ANC prevalence data from health centres run by Médecins Sans Frontières in the Democratic Republic of Congo, which implement routine intermittent screening and treatment alongside intermittent preventative treatment in pregnancy. These statistical models enable the temporal relationship between the two metrics to be disentangled.

RESULTS

There was a strong relationship between the ANC prevalence and clinical incidence suggesting that both can be used to describe current malaria endemicity. There was no evidence that ANC prevalence could predict future clinical incidence, though a change in clinical incidence was shown to influence ANC prevalence up to 3 months into the future.

CONCLUSIONS

The results indicate that ANC prevalence may be a suitable metric for retrospective evaluations of the impact of malaria interventions and is a useful method for evaluating long-term malaria trends in resource constrained settings.

Documenting and explaining the HIV decline in east Zimbabwe: the Manicaland General Population Cohort

PURPOSE

The Manicaland cohort was established to provide robust scientific data on HIV prevalence and incidence, patterns of sexual risk behaviour and the demographic impact of HIV in a sub-Saharan African population subject to a generalised HIV epidemic. The aims were later broadened to include provision of data on the coverage and effectiveness of national HIV control programmes including antiretroviral therapy (ART).

PARTICIPANTS

General population open cohort located in 12 sites in Manicaland, east Zimbabwe, representing 4 major socioeconomic strata (small towns, agricultural estates, roadside settlements and subsistence farming areas). 9,109 of 11,453 (79.5%) eligible adults (men 17-54 years; women 15-44 years) were recruited in a phased household census between July 1998 and January 2000. Five rounds of follow-up of the prospective household census and the open cohort were conducted at 2-year or 3-year intervals between July 2001 and November 2013. Follow-up rates among surviving residents ranged between 77.0% (over 3 years) and 96.4% (2 years).

FINDINGS TO DATE

HIV prevalence was 25.1% at baseline and had a substantial demographic impact with 10-fold higher mortality in HIV-infected adults than in uninfected adults and a reduction in the growth rate in the worst affected areas (towns) from 2.9% to 1.0%pa. HIV infection rates have been highest in young adults with earlier commencement of sexual activity and in those with older sexual partners and larger numbers of lifetime partners. HIV prevalence has since fallen to 15.8% and HIV incidence has also declined from 2.1% (1998-2003) to 0.63% (2009-2013) largely due to reduced sexual risk behaviour. HIV-associated mortality fell substantially after 2009 with increased availability of ART.

FUTURE PLANS

We plan to extend the cohort to measure the effects on the epidemic of current and future HIV prevention and treatment programmes. Proposals for access to these data and for collaboration are welcome.

Providing a conceptual framework for HIV prevention cascades and assessing feasibility of empirical measurement with data from east Zimbabwe: a case study

Background

The HIV treatment cascade illustrates the steps required for successful treatment and is a powerful advocacy and monitoring tool. Similar cascades for people susceptible to infection could improve HIV prevention programming. We aim to show the feasibility of using cascade models to monitor prevention programmes.

Methods

Conceptual prevention cascades are described taking intervention-centric and client-centric perspectives to look at supply, demand, and efficacy of interventions. Data from two rounds of a population-based study in east Zimbabwe are used to derive the values of steps for cascades for voluntary medical male circumcision (VMMC) and for partner reduction or condom use driven by HIV testing and counselling (HTC).

Findings

In 2009 to 2011 the availability of circumcision services was negligible, but by 2012 to 2013 about a third of the population had access. However, where it was available only 12% of eligible men sought to be circumcised leading to an increase in circumcision prevalence from 3·1% to 6·9%. Of uninfected men, 85·3% did not perceive themselves to be at risk of acquiring HIV. The proportions of men and women tested for HIV increased from 27·5% to 56·6% and from 61·1% to 79·6%, respectively, with 30·4% of men tested self-reporting reduced sexual partner numbers and 12·8% reporting increased condom use.

Interpretation

Prevention cascades can be populated to inform HIV prevention programmes. In eastern Zimbabwe programmes need to provide greater access to circumcision services and the design and implementation of associated demand creation activities. Whereas, HTC services need to consider how to increase reductions in partner numbers or increased condom use or should not be considered as contributing to prevention services for the HIV-negative adults.

Funding

Wellcome Trust and Bill & Melinda Gates Foundation.

Empirical validation of the UNAIDS Spectrum model for subnational HIV estimates: case-study of children and adults in Manicaland, Zimbabwe

BACKGROUND

More cost-effective HIV control may be achieved by targeting geographical areas with high infection rates. The AIDS Impact model of Spectrum - used routinely to produce national HIV estimates - could provide the required subnational estimates but is rarely validated with empirical data, even at a national level.

DESIGN

The validity of the Spectrum model estimates were compared with empirical estimates.

METHODS

Antenatal surveillance and population survey data from a population HIV cohort study in Manicaland, East Zimbabwe, were input into Spectrum 5.441 to create a simulation representative of the cohort population. Model and empirical estimates were compared for key demographic and epidemiological outcomes. Alternative scenarios for data availability were examined and sensitivity analyses were conducted for model assumptions considered important for subnational estimates.

RESULTS

Spectrum estimates generally agreed with observed data but HIV incidence estimates were higher than empirical estimates, whereas estimates of early age all-cause adult mortality were lower. Child HIV prevalence estimates matched well with the survey prevalence among children. Estimated paternal orphanhood was lower than empirical estimates. Including observations from earlier in the epidemic did not improve the HIV incidence model fit. Migration had little effect on observed discrepancies - possibly because the model ignores differences in HIV prevalence between migrants and residents.

CONCLUSION

The Spectrum model, using subnational surveillance and population data, provided reasonable subnational estimates although some discrepancies were noted. Differences in HIV prevalence between migrants and residents may need to be captured in the model if applied to subnational epidemics.

Does nonlocal women's attendance at antenatal clinics distort HIV prevalence surveillance estimates in pregnant women in Zimbabwe?

OBJECTIVE

The objective was to assess whether HIV prevalence measured among women attending antenatal clinics (ANCs) are representative of prevalence in the local area, or whether estimates may be biased by some women's choice to attend ANCs away from their residential location. We tested the hypothesis that HIV prevalence in towns and periurban areas is underestimated in ANC sentinel surveillance data in Zimbabwe.

METHODS

National unlinked anonymous HIV surveillance was conducted at 19 ANCs in Zimbabwe in 2000, 2001, 2002, 2004, 2006, 2009, and 2012. This data was used to compare HIV prevalence and nonlocal attendance levels at ANCs at city, town, periurban, and rural clinics in aggregate and also for individual ANCs.

RESULTS

In 2000, HIV prevalence at town ANCs (36.6%, 95% CI 34.4-38.9%) slightly underestimated prevalence among urban women attending these clinics (40.7%, 95% CI 37.6-43.9%). However, there was no distortion in HIV prevalence at either the aggregate clinic location or at individual clinics in more recent surveillance rounds. HIV prevalence was consistently higher in towns and periurban areas than in rural areas. Nonlocal attendance was high at town (26-39%) and periurban (53-95%) ANCs but low at city clinics (<10%). However, rural women attending ANCs in towns and periurban areas had higher HIV prevalence than rural women attending rural clinics, and were younger, more likely to be single, and less likely to be housewives.

CONCLUSIONS

In Zimbabwe, HIV prevalence among ANC attendees provides reliable estimates of HIV prevalence in pregnant women in the local area.

Cost effectiveness of adding nucleic acid testing to hepatitis B, hepatitis C, and human immunodeficiency virus screening of blood donations in Zimbabwe

BACKGROUND

The aim of this study was to assess the cost effectiveness of introducing individual-donation nucleic acid testing (ID-NAT), in addition to serologic tests, compared with the exclusive use of serologic tests for the identification of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) I and II among blood donors in Zimbabwe.

STUDY DESIGN AND METHODS

The costs, health consequences, and cost effectiveness of adding ID-NAT to serologic tests, compared with serologic testing alone, were estimated from a health care perspective using a decision-analytic model.

RESULTS

The introduction of ID-NAT in addition to serologic tests would lower the risk of HBV, HCV, and HIV transmission to 46.9, 0.3, and 2.7 per 100,000 donations, respectively. ID-NAT would prevent an estimated 25, 6, and 9 HBV, HCV, and HIV transfusion-transmitted infections per 100,000 donations, respectively. The introduction of this intervention would result in an estimated 212 quality-adjusted life-years (QALYs) gained. The incremental cost-effectiveness ratio is estimated at US$17,774/QALY, a value far more than three times the gross national income per capita for Zimbabwe.

CONCLUSION

Although the introduction of NAT could further improve the safety of the blood supply, current evidence suggests that it cannot be considered cost effective. Reducing the test costs for NAT through efficient donor recruitment, negotiating the price of reagents, and the efficient use of technology will improve cost effectiveness.

Impact of ART on the fertility of HIV-positive women in sub-Saharan Africa

OBJECTIVE

Understanding the fertility of HIV-positive women is critical to estimating HIV epidemic trends from surveillance data and to planning resource needs and coverage of prevention of mother-to-child transmission services in sub-Saharan Africa. In the light of the considerable scale-up in antiretroviral therapy (ART) coverage over the last decade, we conducted a systematic review of the impact of ART on the fertility outcomes of HIV-positive women.

METHODS

We searched Medline, Embase, Popline, PubMed and African Index Medicus. Studies were included if they were conducted in sub-Saharan Africa and provided estimates of fertility outcomes (live births or pregnancies) among women on ART relative to a comparison group.

RESULTS

Of 2070 unique references, 18 published papers met all eligibility criteria. Comparisons fell into four categories: fertility of HIV-positive women relative to HIV-negative women; fertility of HIV-positive women on ART compared to those not yet on ART; fertility differences by duration on ART; and temporal trends in fertility among HIV-positive women. Evidence indicates that fertility increases after approximately the first year on ART and that while the fertility deficit of HIV-positive women is shrinking, their fertility remains below that of HIV-negative women. These findings, however, were based on limited data mostly during the period 2005-2010 when ART scaled up.

CONCLUSIONS

Existing data are insufficient to characterise how ART has affected the fertility of HIV-positive women in sub-Saharan Africa. Improving evidence about fertility among women on ART is an urgent priority for planning HIV resource needs and understanding HIV epidemic trends. Alternative data sources such as antenatal clinic data, general population cohorts and population-based surveys can be harnessed to understand the issue.