Poliovirus immunity among pregnant females aged 15-44 years, Namibia, 2010.

BACKGROUND: Poliovirus (PV) antibody seroprevalence studies assess population immunity, verify an immunization program's performance and vaccine efficacy, and guide polio eradication strategy. Namibia experienced a polio outbreak among adults in 2006, yet population seroimmunity was unknown. METHODS: We tested 2061 specimens from Namibian pregnant females aged 15-44 years for neutralizing antibody to PV types 1-3 (PV1-3); all females were sampled during the 2010 National HIV Sentinel Survey. We determined the proportion of females seropositive for PV antibody by 5-year age strata, and analyzed factors associated with seropositivity, including age, gravidity, human immunodeficiency virus (HIV) infection status, residence, and antiretroviral treatment, by log-binomial regression. RESULTS: The seroprevalence was 94.6% for PV1, 97.0% for PV2, and 85.1% for PV3. HIV-positive females had significantly lower seroprevalence than HIV-negative females for PV1 (91.8% vs 95.3%; P<.01) and PV3 (80.0% vs 86.1%; P<.01) but not for PV2 (96.4% vs 97.1%; P=.3). The prevalence ratio of seropositivity for HIV-positive females versus HIV-negative females was 0.95 (95% confidence interval [CI], .92-.98) for PV1, 0.99 (95% CI, .97-1.01) for PV2, and 0.92 (95% CI, .87-.96) for PV3. CONCLUSIONS: Despite relatively high PV seroprevalence, Namibia might remain at risk for a PV outbreak, particularly in lower-seroprevalence populations, such as HIV-positive females. Namibia should continue to maintain high routine polio vaccination coverage.

Limited utility of dried-blood- and plasma spot-based screening for antiretroviral treatment failure with Cobas Ampliprep/TaqMan HIV-1 version 2.0.

The 2013 WHO antiretroviral therapy (ART) guidelines recommend dried blood spots (DBS) as an alternative specimen type for viral load (VL) monitoring. We assessed the programmatic utility of screening for antiretroviral (ARV) treatment failure (TF) at 5,000 and 1,000 copies/ml using DBS and dried plasma spots (DPS) with a commonly used VL assay, the Roche Cobas Ampliprep/Cobas TaqMan V.2.0 (CAP/CTM). Plasma, DBS, and DPS were prepared from 839 whole-blood specimens collected from patients on ART for ≥ 6 months at three public facilities in Namibia. Using the CAP/CTM test, VL were measured in plasma, DBS, and DPS, and the results were compared using the plasma VL as the reference standard. The clinical sensitivities, specificities, and positive (PPV) and negative predictive values (NPV) of DBS at ARV TF diagnostic thresholds of 5,000 copies/ml and 1,000 copies/ml were 0.99, 0.55, 0.33, and 0.99 and 0.99, 0.26, 0.29, and 0.99, respectively, and for DPS at TF diagnostic thresholds of 5,000 copies/ml and 1,000 copies/ml, they were 0.88, 0.98, 0.92, and 0.97 and 0.91, 0.96, 0.89, and 0.97, respectively. The prevalences of TF were overestimated in DBS by 33% and 57% at these two thresholds, respectively. A high rate of false-positive results would occur if the CAP/CTM with DBS were to be used to screen for ARV TF. WHO recommendations for DBS-based VL monitoring should be specific to the VL assay version and type. Despite the better performance of DPS, the programmatic utility for TF screening may be limited by requirements for processing the whole blood at the collection site.

Rubella immunity among pregnant women aged 15-44 years, Namibia, 2010.

BACKGROUND: The level of rubella susceptibility among women of reproductive age in Namibia is unknown. Documenting the risk of rubella will help estimate the potential burden of disease in Namibian women and the risk of congenital rubella syndrome (CRS) in infants, and will guide strategies for the introduction of rubella vaccine. METHODS: A total of 2044 serum samples from pregnant Namibian women aged 15-44 years were tested for rubella immunoglobulin G antibody; the samples were obtained during the 2010 National HIV Sentinel Survey. The proportion of women seropositive for rubella was determined by 5-year age strata, and factors associated with seropositivity were analyzed by logistic regression, including age, gravidity, HIV status, facility type, and urban/rural status. RESULTS: Overall rubella seroprevalence was 85% (95% confidence interval (CI) 83-86%). Seroprevalence varied by age group (83-90%) and health district (71-100%). In the multivariable model, women from urban residences had higher odds of seropositivity as compared to women from rural residences (odds ratio 1.40, 95% CI 1.09-1.81). CONCLUSIONS: In the absence of a routine rubella immunization program, the high level of rubella seropositivity suggests rubella virus transmission in Namibia, yet 15% of pregnant Namibian women remain susceptible to rubella. The introduction of rubella vaccine will help reduce the risk of rubella in pregnant women and CRS in infants.

Measles immunity among pregnant women aged 15-44 years in Namibia, 2008 and 2010.

BACKGROUND: Namibia experienced a large measles outbreak starting in 2009, with 38% of reported cases in adults, including women of reproductive age. Population immunity was assessed among pregnant women to determine whether immunization activities were needed in adults to achieve measles elimination in Namibia. METHODS: A total of 1708 and 2040 specimens sampled from Namibian pregnant women aged 15-44 years who were included in the 2008 and 2010 National HIV Sentinel Survey, respectively, were tested for measles immunoglobulin G antibody. The proportion of women seropositive overall and by 5-year age strata was determined, and factors associated with seropositivity were analyzed by logistic regression, including age, facility type, gravidity, HIV status, and urban/rural setting. Seropositivity in 2008 versus 2010 was compared. RESULTS: In both analysis years, measles seropositivity was lower in 15-19-year-olds (77%) and 20-24-year-olds (85-87%) and higher in 25-44-year-olds (90-94%) (2008, p<0.001; 2010, p<0.001). Overall measles seropositivity did not differ between 2008 (87%) and 2010 (87%) (p=0.7). HIV status did not affect seropositivity. CONCLUSIONS: Late in a large measles outbreak, 13% of pregnant women in Namibia, and almost one in four 15-19-year-old pregnant women, remained susceptible to measles. In Namibia, immunization campaigns with measles-containing vaccine should be considered for adults.

Frequency of Pneumocystis jirovecii in sputum from HIV and TB patients in Namibia.

INTRODUCTION: The opportunistic fungus Pneumocystis jirovecii causes Pneumocystis pneumonia (PcP), which is a life-threatening infection in HIV/AIDS patients. The seemingly low prevalence of P. jirovecii pneumonia in sub-Saharan Africa has been a matter of great debate because many HIV/AIDS patients reside in this region. The lack of suitable diagnostic practices in this resource limited-region has been added to the uncertainty of PcP prevalence. Only a few studies have evaluated the utility of easily obtainable samples such as expectorated sputum for diagnosis of PcP. Thus, the aim of the current study was to evaluate the effectiveness of expectorated sputum for the routine diagnosis of PcP in a resource-limited sub-Saharan African setting. METHODOLOGY: Randomly collected sputum samples were analysed by microscopy after Grocott's methenamine silver (GMS) stain staining and by qPCR to determine the minimum frequency of detectable P. jirovecii. RESULTS: A total of 475 samples were analysed. Twenty five (5.3%) samples were positive for P. jirovecii, i.e., 17 (3.6%) using both qPCR and GMS staining and eight (1.7%) using qPCR only. P. jirovecii was present in 8/150 (5.3%) HIV-positive and tuberculosis (TB) smear-negative patients, and in 12/227 (5.3%) TB smear-negative patients with an unknown HIV status. The minimum frequency of PcP was 3.6% in Namibian HIV and TB patients, while the actual frequency is likely to be 5.3%. CONCLUSION: This study demonstrated that expectorated sputum can be used routinely for the diagnosis of PcP by GMS, although qPCR is more sensitive, and it requires less time and skill.

University students and HIV in Namibia: an HIV prevalence survey and a knowledge and attitude survey.

BACKGROUND: With an overall adult HIV prevalence of 15.3%, Namibia is facing one of the largest HIV epidemics in Africa. Young people aged 20 to 34 years constitute one of the groups at highest risk of HIV infection in Namibia. However, little is known about the impact of HIV on this group and its access to healthcare. The purpose of this study was to estimate HIV prevalence, to assess the knowledge of and attitudes towards HIV/AIDS, and to assess access to healthcare among university students in Namibia. METHODS: We assessed HIV/AIDS knowledge and attitudes, HIV prevalence and access to healthcare among students at the Polytechnic of Namibia and the University of Namibia. HIV prevalence was tested through anonymous oral fluid-based tests. RESULTS: Half (n = 2790/5568) of the university students and 45% (n = 2807/6302) of the Polytechnic students participated in the knowledge and attitudes surveys. HIV/AIDS knowledge was reasonable, except for misperceptions about transmission. Awareness of one's own HIV status and risks was low. In all, 55% (n = 3055/5568) of university students and 58% (n = 3680/6302) of Polytechnic students participated in the HIV prevalence survey; 54 (1.8%) university students and 103 (2.8%) Polytechnic students tested HIV positive. Campus clinics were not the major providers of healthcare to the students. CONCLUSIONS: Meaningful strategies addressing the gap between knowledge, attitude and young people's perception of risk of HIV acquisition should be implemented. HIV prevalence among Namibian university students appears relatively low. Voluntary counselling and testing should be stimulated. Efforts should be made to increase access to healthcare through the campus clinics.

Hypertension in sub-Saharan Africa: cross-sectional surveys in four rural and urban communities.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of adult mortality in low-income countries but data on the prevalence of cardiovascular risk factors such as hypertension are scarce, especially in sub-Saharan Africa (SSA). This study aims to assess the prevalence of hypertension and determinants of blood pressure in four SSA populations in rural Nigeria and Kenya, and urban Namibia and Tanzania. METHODS AND FINDINGS: We performed four cross-sectional household surveys in Kwara State, Nigeria; Nandi district, Kenya; Dar es Salaam, Tanzania and Greater Windhoek, Namibia, between 2009-2011. Representative population-based samples were drawn in Nigeria and Namibia. The Kenya and Tanzania study populations consisted of specific target groups. Within a final sample size of 5,500 households, 9,857 non-pregnant adults were eligible for analysis on hypertension. Of those, 7,568 respondents ≥ 18 years were included. The primary outcome measure was the prevalence of hypertension in each of the populations under study. The age-standardized prevalence of hypertension was 19.3% (95%CI:17.3-21.3) in rural Nigeria, 21.4% (19.8-23.0) in rural Kenya, 23.7% (21.3-26.2) in urban Tanzania, and 38.0% (35.9-40.1) in urban Namibia. In individuals with hypertension, the proportion of grade 2 (≥ 160/100 mmHg) or grade 3 hypertension (≥ 180/110 mmHg) ranged from 29.2% (Namibia) to 43.3% (Nigeria). Control of hypertension ranged from 2.6% in Kenya to 17.8% in Namibia. Obesity prevalence (BMI ≥ 30) ranged from 6.1% (Nigeria) to 17.4% (Tanzania) and together with age and gender, BMI independently predicted blood pressure level in all study populations. Diabetes prevalence ranged from 2.1% (Namibia) to 3.7% (Tanzania). CONCLUSION: Hypertension was the most frequently observed risk factor for CVD in both urban and rural communities in SSA and will contribute to the growing burden of CVD in SSA. Low levels of control of hypertension are alarming. Strengthening of health care systems in SSA to contain the emerging epidemic of CVD is urgently needed.

Incidence of HIV in Windhoek, Namibia: demographic and socio-economic associations.

OBJECTIVE: To estimate HIV incidence and prevalence in Windhoek, Namibia and to analyze socio-economic factors related to HIV infection. METHOD: In 2006/7, baseline surveys were performed with 1,753 private households living in the greater Windhoek area; follow-up visits took place in 2008 and 2009. Face-to-face socio-economic questionnaires were administrated by trained interviewers; biomedical markers were collected by nurses; GPS codes of household residences were recorded. RESULTS: The HIV prevalence in the population (aged>12 years) was 11.8% in 2006/7 and 14.6% in 2009. HIV incidence between 2007 and 2009 was 2.4 per 100 person year (95%CI = 1.9-2.9). HIV incidence and prevalence were higher in female populations. HIV incidence appeared non-associated with any socioeconomic factor, indicating universal risk for the population. For women a positive trend was found between low per-capita consumption and HIV acquisition. A HIV knowledge score was strongly associated with HIV incidence for both men and women. High HIV prevalence and incidence was concentrated in the north-western part of the city, an area with lower HIV knowledge, higher HIV risk perception and lower per-capita consumption. DISCUSSION: The HIV incidence and prevalence figures do not suggest a declining epidemic in Windhoek. Higher vulnerability of women is recorded, most likely related to economic dependency and increasing transactional sex in Namibia. The lack of relation between HIV incidence and socio-economic factors confirms HIV risks for the overall urban community. Appropriate knowledge is strongly associated to lower HIV incidence and prevalence, underscoring the importance of continuous information and education activities for prevention of infection. Geographical areas were identified that would require prioritized HIV campaigning.

Anonymous HIV workplace surveys as an advocacy tool for affordable private health insurance in Namibia.

BACKGROUND: With an estimated adult HIV prevalence of 15%, Namibia is in need of innovative health financing strategies that can alleviate the burden on the public sector. Affordable and private health insurances were recently developed in Namibia, and they include coverage for HIV/AIDS. This article reports on the efficacy of HIV workplace surveys as a tool to increase uptake of these insurances by employees in the Namibian formal business sector. In addition, the burden of HIV among this population was examined by sector. METHODS: Cross-sectional anonymous HIV prevalence surveys were conducted in 24 private companies in Namibia between November 2006 and December 2007. Non-invasive oral fluid-based HIV antibody rapid tests were used. Anonymous test results were provided to the companies in a confidential report and through presentations to their management, during which the advantages of affordable private health insurance and the available insurance products were discussed. Impact assessment was conducted in October 2008, when new health insurance uptake by these companies was evaluated. RESULTS: Of 8500 targeted employees, 6521 were screened for HIV; mean participation rate was 78.6%. Overall 15.0% (95% CI 14.2-15.9%) of employees tested HIV positive (range 3.0-23.9% across companies). The mining sector had the highest percentage of HIV-positive employees (21.0%); the information technology (IT) sector had the lowest percentage (4.0%). Out of 6205 previously uninsured employees, 61% had enrolled in private health insurance by October 2008. The majority of these new insurances (78%) covered HIV/AIDS only. CONCLUSION: The proportion of HIV-positive formal sector employees in Namibia is in line with national prevalence estimates and varies widely by employment sector. Following the surveys, there was a considerable increase in private health insurance uptake. This suggests that anonymous HIV workplace surveys can serve as a tool to motivate private companies to provide health insurance to their workforce. Health insurance taken up by those who are able to pay the fees will alleviate the burden on the public sector.