HIV Prevalence, Risk Factors for Infection, and Uptake of Prevention, Testing, and Treatment among Female Sex Workers in Namibia

Background: In most settings, Female Sex Workers (FSW) bear a disproportionate burden of Human Immunodeficiency Virus (HIV) disease worldwide. Representative data to inform the development of behavioral and biomedical interventions for FSW in Namibia have not been published.

Objectives: Our objectives were to measure HIV prevalence, identify risk factors for infection, and describe uptake of prevention, testing, and treatment among FSW in Namibia.

Methods: We conducted cross-sectional surveys using Respondent-driven Sampling (RDS) in the Namibian cities of Katima Mulilo, Oshikango, Swakopmund/Walvis Bay, and Windhoek. Participating FSW completed behavioral questionnaires and rapid HIV testing.

Results: City-specific ranges of key indicators were: HIV prevalence (31.0–52.3%), reached by prevention programs in the past 12 months (46.9–73.6%), condom use at last sex with commercial (82.1–91.1%) and non-commercial (87.0–94.2%) partners, and tested for HIV within past 12 months or already aware of HIV-positive serostatus (56.9–82.1%). Factors associated with HIV infection varied by site and included: older age, having multiple commercial or non-commercial sex partners, unemployment, being currently out of school, and lower education level. Among HIV-positive FSW, 57.1% were aware of their HIV-positive serostatus and 33.7% were on antiretroviral treatment.

Discussion: Our results indicate extremely high HIV prevalence and low levels of case identification and treatment among FSW in Namibia. Our results, which are the first representative community-based estimates among FSW in Namibia, can inform the scale-up of interventions to reduce the risk for HIV acquisition and onward transmission, including treatment as prevention and pre-exposure prophylaxis.

Estimating the Population Size of Female Sex Workers in Namibia Using a Respondent-Driven Sampling Adjustment to the Reverse Tracking Method: A Novel Approach

BACKGROUND

Key populations, including female sex workers (FSWs), are at a disproportionately high risk for HIV infection. Estimates of the size of these populations serve as denominator data to inform HIV prevention and treatment programming and are necessary for the equitable allocation of limited public health resources.

OBJECTIVE

This study aimed to present the respondent-driven sampling (RDS) adjusted reverse tracking method (RTM; RadR), a novel population size estimation approach that combines venue mapping data with RDS data to estimate the population size, adjusted for double counting and nonattendance biases.

METHODS

We used data from a 2014 RDS survey of FSWs in Windhoek and Katima Mulilo, Namibia, to demonstrate the RadR method. Information from venue mapping and enumeration from the survey formative assessment phase were combined with survey-based venue-inquiry questions to estimate population size, adjusting for double counting, and FSWs who do not attend venues. RadR estimates were compared with the official population size estimates, published by the Namibian Ministry of Health and Social Services (MoHSS), and with the unadjusted RTM.

RESULTS

Using the RadR method, we estimated 1552 (95% simulation interval, SI, 1101-2387) FSWs in Windhoek and 453 (95% SI: 336-656) FSWs in Katima Mulilo. These estimates were slightly more conservative than the MoHSS estimates-Windhoek: 3000 (1800-3400); Katima Mulilo: 800 (380-2000)-though not statistically different. We also found 75 additional venues in Windhoek and 59 additional venues in Katima Mulilo identified by RDS participants' responses that were not detected during the initial mapping exercise.

CONCLUSIONS

The RadR estimates were comparable with official estimates from the MoHSS. The RadR method is easily integrated into RDS studies, producing plausible population size estimates, and can also validate and update key population maps for outreach and venue-based sampling.

Maternal, fetal, and neonatal outcomes associated with measles during pregnancy: Namibia, 2009-2010

BACKGROUND

Previous studies of maternal, fetal, and neonatal complications of measles during pregnancy suggest the possibility of increased risk for morbidity and mortality. In 2009-2011, a nationwide laboratory-confirmed measles outbreak occurred in Namibia, with 38% of reported cases among adults. This outbreak provided an opportunity to describe clinical features of measles in pregnant women and assess the relative risk for adverse maternal, fetal, and neonatal outcomes.

METHODS

A cohort of pregnant women with clinical measles was identified retrospectively from 6 district hospitals and clinics over a 12-month period. Each pregnant woman with measles was matched with 3 pregnant women without measles, randomly selected from antenatal clinic registers at the same hospital during the same time interval. We reviewed hospital and clinic records and conducted in-person interviews to collect demographic and clinical information on the pregnant women and their infants.

RESULTS

Of 55 pregnant women with measles, 53 (96%) were hospitalized; measles-related complications included diarrhea (60%), pneumonia (40%), and encephalitis (5%). Among pregnant women with known human immunodeficiency virus (HIV) status, 15% of those without measles and 19% of those with measles were HIV positive. Of 42 measles-related pregnancies with known outcomes, 25 (60%) had ≥1 adverse maternal, fetal, or neonatal outcome and 5 women (12%) died. Compared with 172 pregnancies without measles, after adjusting for age, pregnancies with measles carried significantly increased risks for neonatal low birth weight (adjusted relative risk [aRR] = 3.5; 95% confidence interval [CI], 1.5-8.2), spontaneous abortion (aRR = 5.9; 95% CI, 1.8-19.7), intrauterine fetal death (aRR = 9.0; 95% CI, 1.2-65.5), and maternal death (aRR = 9.6; 95% CI, 1.3-70.0).

CONCLUSIONS

Our findings suggest that measles virus infection during pregnancy confers a high risk of adverse maternal, fetal, and neonatal outcomes, including maternal death. Maximizing measles immunity among women of childbearing age would decrease the incidence of gestational measles and the attendant maternal, fetal, and neonatal morbidity and mortality.