SUNScholar - Browsing by Author "Middelkoop, Keren"

Browsing by Author "Middelkoop, Keren"

Now showing 1 - 6 of 6

Burden of new and recurrent tuberculosis in a major South African city stratified by age and HIV-status
(Public Library of Science, 2011-10-10) Wood, Robin; Lawn, Stephen D.; Caldwell, Judy; Kaplan, Richard; Middelkoop, Keren; Bekker, Linda-Gail
Aim To describe the burden of tuberculosis (TB) in Cape Town by calculating TB incidence rates stratified by age and HIV-status, assessing the contribution of retreatment disease and estimating the cumulative lifetime TB risk in HIV-negative individuals. Methods Details of TB cases were abstracted from the 2009 electronic TB register. Population denominators were estimated from census data and actuarial estimates of HIV prevalence, allowing calculation of age-specific and HIV-stratified TB notification rates. Results The 2009 mid-year population was 3,443,010 (3,241,508 HIV-negative and 201,502 HIV-positive individuals). There were 29,478 newly notified TB cases of which 56% were laboratory confirmed. HIV status was recorded for 87% of cases and of those with known HIV-status 49% were HIV-negative and 51% were positive. Discrete peaks in the incidence of non-HIV-associated TB occurred at three ages: 511/100,000 at 0–4 years of age, 553/100,000 at 20–24 years and 628/100,000 at 45–49 years with 1.5%, 19% and 45% being due to retreatment TB, respectively. Only 15.5% of recurrent cases had a history of TB treatment failure or default. The cumulative lifetime risks in the HIV-negative population of all new TB episodes and new smear-positive TB episodes were 24% and 12%, respectively; the lifetime risk of retreatment disease was 9%. The HIV-positive notification rate was 6,567/100,000 (HIV-associated TB rate ratio = 17). Although retreatment cases comprised 30% of the HIV-associated TB burden, 88% of these patients had no history of prior treatment failure or default. Conclusions The annual burden of TB in this city is huge. TB in the HIV-negative population contributed almost half of the overall disease burden and cumulative lifetime risks were similar to those reported in the pre-chemotherapy era. Retreatment TB contributed significantly to both HIV-associated and non-HIV-associated TB but infrequently followed prior inadequate treatment. This likely reflects ongoing TB transmission to both HIV-negative and positive individuals.
High prevalence of self-reported undiagnosed HIV despite high coverage of HIV testing : a cross-sectional population based sero-survey in South Africa
(Public Library of Science, 2011-09-28) Kranzer, Katharina; Van Schaik, Nienke; Karmue, Unice; Middelkoop, Keren; Sebastian, Elaine; Lawn, Stephen D.; Wood, Robiin; Bekker, Linda-Gail
Objectives To measure HIV prevalence and uptake of HIV counseling and testing (HCT) in a peri-urban South African community. To assess predictors for previous HIV testing and the association between the yield of previously undiagnosed HIV and time of last negative HIV test Methods A random sample of 10% of the adult population (≥15 years) were invited to attend a mobile HCT service. Study procedures included a questionnaire, HIV testing and CD4 counts. Predictors for previous testing were determined using a binominal model. Results 1,144 (88.0%) of 1,300 randomly selected individuals participated in the study. 71.0% (68.3–73.6) had previously had an HIV test and 37.5% (34.6–40.5) had tested in the past 12 months. Men, migrants and older (>35 years) and younger (<20 years) individuals were less likely to have had a previous HIV test. Overall HIV prevalence was 22.7 (20.3–25.3) with peak prevalence of 41.8% (35.8–47.8) in women aged 25.1–35 years and 37.5% (26.7–48.3) in men aged 25.1–45 years. Prevalence of previously undiagnosed HIV was 10.3% (8.5–12.1) overall and 4.5% (2.3–6.6), 8.0% (CI 3.9–12.0) and 20.0% (13.2–26.8) in individuals who had their most recent HIV test within 1, 1–2 and more than 2 years prior to the survey. Conclusion The high burden of undiagnosed HIV in individuals who had recently tested underscores the importance of frequent repeat testing at least annually. The high prevalence of previously undiagnosed HIV in individuals reporting a negative test in the 12 months preceding the survey indicates a very high incidence. Innovative prevention strategies are needed.
Indoor social networks in a South African township : potential contribution of location to tuberculosis transmission
(Public Library of Science, 2012-06-29) Wood, Robin; Racow, Kimberly; Bekker, Linda-Gail; Morrow, Carl; Middelkoop, Keren; Mark, Daniella; Lawn, Stephen D.
Background We hypothesized that in South Africa, with a generalized tuberculosis (TB) epidemic, TB infection is predominantly acquired indoors and transmission potential is determined by the number and duration of social contacts made in locations that are conducive to TB transmission. We therefore quantified time spent and contacts met in indoor locations and public transport by residents of a South African township with a very high TB burden. Methods A diary-based community social mixing survey was performed in 2010. Randomly selected participants (n = 571) prospectively recorded numbers of contacts and time spent in specified locations over 24-hour periods. To better characterize age-related social networks, participants were stratified into ten 5-year age strata and locations were classified into 11 types. Results Five location types (own-household, other-households, transport, crèche/school, and work) contributed 97.2% of total indoor time and 80.4% of total indoor contacts. Median time spent indoors was 19.1 hours/day (IQR:14.3–22.7), which was consistent across age strata. Median daily contacts increased from 16 (IQR:9–40) in 0–4 year-olds to 40 (IQR:18–60) in 15–19 year-olds and declined to 18 (IQR:10–41) in ≥45 year-olds. Mean daily own-household contacts was 8.8 (95%CI:8.2–9.4), which decreased with increasing age. Mean crèche/school contacts increased from 6.2/day (95%CI:2.7–9.7) in 0–4 year-olds to 28.1/day (95%CI:8.1–48.1) in 15–19 year-olds. Mean transport contacts increased from 4.9/day (95%CI:1.6–8.2) in 0–4 year-olds to 25.5/day (95%CI:12.1–38.9) in 25–29 year-olds. Conclusions A limited number of location types contributed the majority of indoor social contacts in this community. Increasing numbers of social contacts occurred throughout childhood, adolescence, and young adulthood, predominantly in school and public transport. This rapid increase in non-home socialization parallels the increasing TB infection rates during childhood and young adulthood reported in this community. Further studies of the environmental conditions in schools and public transport, as potentially important locations for ongoing TB infection, are indicated.
Lipoarabinomannan in urine during tuberculosis treatment : association with host and pathogen factors and mycobacteriuria
(BioMed Central, 2012-02) Wood, Robin; Racow, Kimberly; Bekker, Linda-Gail; Middelkoop, Keren; Vogt, Monica; Kreiswirth, Barry N.; Lawn, Stephen D.
Socio-behaviour challenges to phase III HIV vaccine trials in Sub-Saharan Africa
(Makerere University Medical School, 2005-09) Smit, Joalida; Middelkoop, Keren; Myer, Landon; Lindegger, Graham; Swartz, Leslie; Seedat, Soraya; Tucker, Tim; Wood, Robin; Bekker, Linda-Gail; Stein, Dan J.
Background: A number of countries in sub-Saharan Africa are preparing for HIV vaccine efficacy trials. Social and behavioural factors related to HIV transmission require examination in each setting where these trials are considered. As part of this, several countries have also recently begun preparatory research investigating relevant social and behavioural issues. There is a need for a review of the literature to help focus such research efforts in Sub-Saharan Africa. Objective: To examine key social and behavioural issues that may impact on the conduct of HIV vaccine efficacy trials in sub- Saharan Africa. Design: Literature review Methods: Major databases (PubMed, PsychInfo, EBSCOhost, and AIDSline) were searched for literature that discussed social and behavioural issues related to HIV vaccine trials. Three areas are highlighted as being particularly significant for HIV vaccine research: (1) willingness to participate in future HIV vaccine efficacy trials, (2) retention of participants in studies, and (3) sexual risk reporting during trials. For each of these topics, major findings from both developed and developing countries are described and avenues for further research are discussed. Results: There are few data from Sub-Saharan Africa regarding willingness to participate in HIV vaccine trials. Data on participant retention rates varies widely, and maintaining large cohorts of individuals within Phase III trials presents an important challenge. In addition, the possible impact of trial participation on sexual disinhibition, and response bias on sexual risk-reporting remain as issues for HIV vaccine trials in African contexts. Conclusions: Social and behavioural research forms an important part of preparations for HIV vaccine efficacy trials, and there is a clear need for more research of this type in Sub-Saharan Africa. Innovative approaches are required to address issues such as willingness to participate in vaccine research, participant retention during efficacy trials, and the accurate reporting by participants of sexual risk behaviours.
TB transmission is associated with prolonged stay in a low socio-economic, high burdened TB and HIV community in Cape Town, South Africa
(BMC (part of Springer Nature), 2020-02-10) Tadokera, Rebecca; Bekker, Linda-Gail; Kreiswirth, Barry N.; Mathema, Barun; Middelkoop, Keren
Background: While several studies have assessed the associations between biological factors and tuberculosis (TB) transmission, our understanding of the associations between TB transmission and social and economic factors remains incomplete. We aimed to explore associations between community TB transmission and socio-economic factors within a high TB-HIV burdened setting. Methods: We conducted a cross-sectional molecular epidemiology study among adult patients attending a routine TB clinic. Demographic and clinical data were extracted from TB registers and clinical folders; social and economic data were collected using interviewer-administered questionnaires; Mycobacterium tuberculosis isolates were genotyped and classified as clustered/non-clustered using IS6110-based Restriction Fragment Length Polymorphism. Composite “social” and “economic” scores were generated from social and economic data. Data were analyzed using StataCorp version 15.0 software. Stratified, bivariable analyses were performed using chisquared. Wilcoxon signed rank tests; univariable and multivariable logistic regression models were developed to explore associations in the social, economic, traditional and composite TB risk factors with TB transmission. Results: Of the 505 patient Mtb strains, 348(69%) cases were classified as clustered and 157(31%) were nonclustered. Clustered cases were more likely to have lived longer in the study community, (odds ratio [OR] = 1.05, 95% Confidence interval [C.I]:1.02–1.09, p = 0.006); in the same house (OR = 1.04, C.I: 0.99–1.08, p = 0.06); and had increased household crowding conditions (i.e fewer rooms used for sleeping, OR = 0.45, C.I:0.21–0.95, p = 0.04). Although a higher proportion of clustered cases had a low economic score, no statistically significant association was found between clustering and either the economic score (p = 0.13) or social score (p = 0.26). Conclusions: We report a novel association between Mtb transmission and prolonged stay within a high burdened community. Transmission was also associated with fewer rooms for sleeping in a household. Increased social interaction and prolonged residence in a high burdened community are important factors linked to Mtb transmission, possibly due to increased probability of higher effective contact rates. The possible importance of degrees of poverty within low socio-economic setting warrants further study.

Browsing by Author "Middelkoop, Keren"

Results Per Page

Sort Options