Peter W. Young
Centers for Disease Control and Prevention
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Featured researches published by Peter W. Young.
BMC Infectious Diseases | 2013
Peter W. Young; Mussagy Mahomed; Roberta Horth; Ray W. Shiraishi; Ilesh V Jani
BackgroundOpt-out HIV testing is offered at 70% of antenatal care (ANC) clinics in Mozambique through the prevention of mother-to-child transmission (PMTCT) program. If routine data from this program were of sufficient quality, their heightened coverage and continuous availability could complement or even replace biannual sentinel serosurveys that currently serve as the primary HIV surveillance system in Mozambique.MethodsWe assessed the efficacy of routine HIV testing data from prevention of mother-to-child transmission programs for estimating the prevalence of HIV infection among pregnant women. The PMTCT program uses sequential point-of-care rapid tests conducted on site while ANC surveillance surveys use dried blood spots tested sequentially for HIV-1/2 antibodies at a central laboratory. We compared matched routine PMTCT and ANC surveillance test results collected during 2007 and 2009 ANC surveillance surveys from 36 sentinel sites.ResultsAfter excluding 659 women without PMTCT data, including 83 who refused rapid testing, test results from a total of 20,563 women were available. Pooling the data from both years indicated HIV prevalence from routine PMTCT testing was 14.4% versus 15.2% from surveillance testing (relative difference -5.1%; absolute difference -0.78%). Positive percent agreement (PPA) of PMTCT versus surveillance tests was 88.5% (95% Confidence Interval [CI]: 85.7-91.3%), with 19 sites having PPA below 90%; Negative percent agreement (NPA) was 98.9% (CI: 98.5-99.2%). No significant difference was found among three regions (North, Center and South), however both PPA and NPA were significantly higher in 2009 than 2007 (p < 0.05).ConclusionsWe found low PPA of PMTCT test results compared to surveillance data which is indicative either of testing errors or data reporting problems. Nonetheless, PPA improved significantly from 2007 to 2009, a possible positive trend that should be investigated further. Although use of PMTCT test results would not dramatically change HIV prevalence estimates among pregnant women, the impact of site-level differences on surveillance models should be evaluated before these data are used to replace or complement ANC surveillance surveys.
PLOS ONE | 2014
E. Kainne Dokubo; Ray W. Shiraishi; Peter W. Young; Joyce J. Neal; John Aberle-Grasse; Nely Honwana; Francisco Mbofana
Objective To determine factors associated with HIV status unawareness and assess HIV prevention knowledge and condom use among people living with HIV/AIDS (PLHIV) in Mozambique. Design Cross-sectional household-based nationally representative AIDS Indicator Survey. Methods Analyses focused on HIV-infected adults and were weighted for the complex sampling design. We identified PLHIV who had never been tested for HIV or received their test results prior to this survey. Logistic regression was used to assess factors associated with HIV status unawareness. Results Of persons with positive HIV test results (N = 1182), 61% (95% confidence interval [CI] 57–65%) were unaware of their serostatus. Men had twice the odds of being unaware of their serostatus compared with women [adjusted odds ratio (aOR) 2.05, CI 1.40–2.98]. PLHIV in the poorest wealth quintile were most likely to be unaware of their serostatus (aOR 3.15, CI 1.09–9.12) compared to those in the middle wealth quintile. Most PLHIV (83%, CI 79–87%) reported not using a condom during their last sexual intercourse, and PLHIV who reported not using a condom during their last sexual intercourse were more likely to be unaware of their serostatus (aOR 2.32, CI 1.57–3.43) than those who used a condom. Conclusions Knowledge of HIV-positive status is associated with more frequent condom use in Mozambique. However, most HIV-infected persons are unaware of their serostatus, with men and persons in the poorest wealth quintile being more likely to be unaware. These findings support calls for expanded HIV testing, especially among groups less likely to be aware of their HIV status and key populations at higher risk for infection.
PLOS ONE | 2013
Dulce Bila; Peter W. Young; Harriet Merks; Adolfo Vubil; Mussagy Mahomed; Angelo Augusto; Celina Monteiro Abreu; Nédio Mabunda; James Brooks; Amilcar Tanuri; Ilesh Jani
Objective In Mozambique, highly active antiretroviral treatment (HAART) was introduced in 2004 followed by decentralization and expansion, resulting in a more than 20-fold increase in coverage by 2009. Implementation of HIV drug resistance threshold surveys (HIVDR-TS) is crucial in order to monitor the emergence of transmitted viral resistance, and to produce evidence-based recommendations to support antiretroviral (ARV) policy in Mozambique. Methods World Health Organization (WHO) methodology was used to evaluate transmitted drug resistance (TDR) in newly diagnosed HIV-1 infected pregnant women attending ante-natal clinics in Maputo and Beira to non-nucleoside reverse transcriptase inhibitors (NNRTI), nucleoside reverse transcriptase inhibitors (NRTI) and protease inhibitors (PI). Subtypes were assigned using REGA HIV-1 subtyping tool and phylogenetic trees constructed using MEGA version 5. Results Although mutations associated with resistance to all three drug were detected in these surveys, transmitted resistance was analyzed and classified as <5% in Maputo in both surveys for all three drug classes. Transmitted resistance to NNRTI in Beira in 2009 was classified between 5–15%, an increase from 2007 when no NNRTI mutations were found. All sequences clustered with subtype C. Conclusions Our results show that the epidemic is dominated by subtype C, where the first-line option based on two NRTI and one NNRTI is still effective for treatment of HIV infection, but intermediate levels of TDR found in Beira reinforce the need for constant evaluation with continuing treatment expansion in Mozambique.
AIDS | 2016
Andrea A. Kim; Peter W. Young; Joy Mirjahangir; Mwanyumba S; Wamicwe J; Bowen N; Wiesner L; Ng'ang'a L; De Cock Km
Objectives:This analysis assessed the impact of undisclosed HIV infection and antiretroviral therapy (ART) on national estimates of diagnosed HIV and ART coverage in Kenya. Methods:HIV-positive dried blood spot samples from Kenyas second AIDS Indicator Survey were tested for an antiretroviral biomarker by liquid chromatography-tandem mass spectrometry. Weighted estimates of diagnosed HIV and ART coverage based on self-report were compared with those corrected for undisclosed HIV infection and ART use based on antiretroviral test results. Multivariate analysis determined factors associated with undisclosed HIV infection and ART use among persons on ART. Results:The antiretroviral biomarker was detected in 42.5% [confidence interval (CI) 37.4–47.7] of HIV-infected persons. Antiretroviral drugs were present in 90.7% (CI 86.1–95.2) of HIV-infected persons reporting HIV-positive status and receiving ART, 66.7% (CI 59.9–73.4) reporting HIV-positive status irrespective of ART use, 21.0% (CI 13.4–28.6) reporting HIV-negative status, and 19.3% (CI 9.0–29.5) reporting no previous HIV test. After correcting for undisclosed HIV infection and ART use, diagnosed HIV increased from 46.9 to 57.2% and ART coverage increased from 31.8 to 42.8%. Undisclosed HIV infection while on ART was associated with being aged 25–39 years and not visiting a health provider in the past year, while younger age and higher wealth were associated with undisclosed ART use. Conclusion:Substantial levels of undisclosed HIV infection and ART use among persons on ART were observed, resulting in diagnosed HIV underestimated by approximately 112000 persons and ART coverage by approximately 131000 persons. Supplementing self-reported ART status with objective measures of ART use in national population-based serosurveys can improve monitoring of HIV diagnosis and treatment targets in countries.
The Lancet HIV | 2018
M. W. Borgdorff; Daniel Kwaro; David Obor; George Otieno; Viviane Kamire; Frederick Odongo; Patrick Owuor; Jacques Muthusi; Lisa A. Mills; Rachael Joseph; Mary E Schmitz; Peter W. Young; Emily Zielinski-Gutierrez; Kevin M. De Cock
BACKGROUND In Kenya, coverage of antiretroviral therapy (ART) among people with HIV infection has increased from 7% in 2006, to 57% in 2016; and, in western Kenya, coverage of voluntary medical male circumcision (VMMC) increased from 45% in 2008, to 72% in 2014. We investigated trends in HIV prevalence and incidence in a high burden area in western Kenya in 2011-16. METHODS In 2011, 2012, and 2016, population-based surveys were done via a health and demographic surveillance system and home-based counselling and testing in Gem, Siaya County, Kenya, including 28 688, 17 021, and 16 772 individuals aged 15-64 years. Data on demographic variables, self-reported HIV status, and risk factors were collected. Rapid HIV testing was offered to survey participants. Participants were tracked between surveys by use of health and demographic surveillance system identification numbers. HIV prevalence was calculated as a proportion, and HIV incidence was expressed as number of new infections per 1000 person-years of follow-up. FINDINGS HIV prevalence was stable in participants aged 15-64 years: 15% (4300/28 532) in 2011, 12% (2051/16 875) in 2012, and 15% (2312/15 626) in 2016. Crude prevalences in participants aged 15-34 years were 11% (1893/17 197) in 2011, 10% (1015/10 118) in 2012, and 9% (848/9125) in 2016; adjusted for age and sex these prevalences were 11%, 9%, and 8%. 12 606 (41%) of the 30 520 non-HIV-infected individuals enrolled were seen again in at least one more survey round, and were included in the analysis of HIV incidence. HIV incidence was 11·1 (95% CI 9·1-13·1) per 1000 person-years from 2011 to 2012, and 5·7 (4·6-6·9) per 1000 person-years from 2012 to 2016. INTERPRETATION With increasing coverage of ART and VMMC, HIV incidence declined substantially in Siaya County between 2011 and 2016. VMMC, but not ART, was suggested to have a direct protective effect, presumably because ART tended to be given to individuals with advanced HIV infection. HIV incidence is still high and not close to the elimination target of one per 1000 person-years. The effect of further scale-up of ART and VMMC needs to be monitored. FUNDING Data were collected under Cooperative Agreements with the US Centers for Disease Control and Prevention, with funding from the Presidents Emergency Fund for AIDS Relief.
PeerJ | 2018
Anthony Waruru; Thomas O. Achia; Hellen Muttai; Lucy Ng’ang’a; Emily Zielinski-Gutierrez; Boniface Ochanda; Abraham Katana; Peter W. Young; James L. Tobias; Peter Juma; Kevin M. De Cock; Thorkild Tylleskär
Introduction Using spatial–temporal analyses to understand coverage and trends in elimination of mother-to-child transmission of HIV (e-MTCT) efforts may be helpful in ensuring timely services are delivered to the right place. We present spatial–temporal analysis of seven years of HIV early infant diagnosis (EID) data collected from 12 districts in western Kenya from January 2007 to November 2013, during pre-Option B+ use. Methods We included in the analysis infants up to one year old. We performed trend analysis using extended Cochran–Mantel–Haenszel stratified test and logistic regression models to examine trends and associations of infant HIV status at first diagnosis with: early diagnosis (<8 weeks after birth), age at specimen collection, infant ever having breastfed, use of single dose nevirapine, and maternal antiretroviral therapy status. We examined these covariates and fitted spatial and spatial–temporal semiparametric Poisson regression models to explain HIV-infection rates using R-integrated nested Laplace approximation package. We calculated new infections per 100,000 live births and used Quantum GIS to map fitted MTCT estimates for each district in Nyanza region. Results Median age was two months, interquartile range 1.5–5.8 months. Unadjusted pooled positive rate was 11.8% in the seven-years period and declined from 19.7% in 2007 to 7.0% in 2013, p < 0.01. Uptake of testing ≤8 weeks after birth was under 50% in 2007 and increased to 64.1% by 2013, p < 0.01. By 2013, the overall standardized MTCT rate was 447 infections per 100,000 live births. Based on Bayesian deviance information criterion comparisons, the spatial–temporal model with maternal and infant covariates was best in explaining geographical variation in MTCT. Discussion Improved EID uptake and reduced MTCT rates are indicators of progress towards e-MTCT. Cojoined analysis of time and covariates in a spatial context provides a robust approach for explaining differences in programmatic impact over time. Conclusion During this pre-Option B+ period, the prevention of mother to child transmission program in this region has not achieved e-MTCT target of ≤50 infections per 100,000 live births. Geographical disparities in program achievements may signify gaps in spatial distribution of e-MTCT efforts and could indicate areas needing further resources and interventions.
PLOS ONE | 2018
Sizulu Moyo; Peter W. Young; Eleanor Gouws; Inbarani Naidoo; Joyce Wamicwe; Irene Mukui; Kimberly Marsh; Ehimario U. Igumbor; Andrea A. Kim; Thomas Rehle
Objective To assess changes and equity in antiretroviral therapy (ART) use in Kenya and South Africa. Methods We analysed national population-based household surveys conducted in Kenya and South Africa between 2007 and 2012 for factors associated with lack of ART use among people living with HIV (PLHIV) aged 15–64 years. We considered ART use to be inequitable if significant differences in use were found between groups of PLHIV (e.g. by sex). Findings ART use among PLHIV increased from 29.3% (95% confidence interval [CI]: 22.8–35.8) to 42.5% (95%CI: 37.4–47.7) from 2007 to 2012 in Kenya and 17.4% (95%CI: 14.2–20.9) to 30.3% (95%CI: 27.2–33.6) from 2008 to 2012 in South Africa. In 2012, factors independently associated with lack of ART use among adult Kenyan PLHIV were rural residency (adjusted odds ratio [aOR] 1.98, 95%CI: 1.23–3.18), younger age (15–24 years: aOR 4.25, 95%CI: 1.7–10.63, and 25–34 years: aOR 5.16, 95%CI: 2.73–9.74 versus 50–64 years), nondisclosure of HIV status to most recent sex partner (aOR 2.41, 95%CI: 1.27–4.57) and recent recreational drug use (aOR 2.50, 95%CI: 1.09–5.77). Among South African PLHIV in 2012, lack of ART use was significantly associated with younger age (15–24 years: aOR 4.23, 95%CI: 2.56–6.70, and 25–34 years: aOR 2.84, 95%CI: 1.73–4.67, versus 50–64 years), employment status (aOR 1.61, 95%CI: 1.16–2.23 in students versus unemployed), and recent recreational drug use (aOR 4.56, 95%CI: 1.79–11.57). Conclusion Although we found substantial increases in ART use in both countries over time, we identified areas needing improvement including among rural Kenyans, students in South Africa, and among young people and drug users in both countries.
PLOS ONE | 2017
Peter W. Young; Andrea A. Kim; Joyce Wamicwe; Lilly Nyagah; Catherine Nduku Kiama; John Stover; Johansen Oduor; Emily Rogena; Edwin Walong; Emily Zielinski-Gutierrez; Andrew Imbwaga; Martin Sirengo; Timothy A. Kellogg; Kevin M. De Cock
Background Declines in HIV prevalence and increases in antiretroviral treatment coverage have been documented in Kenya, but population-level mortality associated with HIV has not been directly measured. In urban areas where a majority of deaths pass through mortuaries, mortuary-based studies have the potential to contribute to our understanding of excess mortality among HIV-infected persons. We used results from a cross-sectional mortuary-based HIV surveillance study to estimate the association between HIV and mortality for Nairobi, the capital city of Kenya. Methods and findings HIV seropositivity in cadavers measured at the two largest mortuaries in Nairobi was used to estimate HIV prevalence in adult deaths. Model-based estimates of the HIV-infected and uninfected population for Nairobi were used to calculate a standardized mortality ratio and population-attributable fraction for mortality among the infected versus uninfected population. Monte Carlo simulation was used to assess sensitivity to epidemiological assumptions. When standardized to the age and sex distribution of expected deaths, the estimated HIV positivity among adult deaths aged 15 years and above in Nairobi was 20.9% (95% CI 17.7–24.6%). The standardized mortality ratio of deaths among HIV-infected versus uninfected adults was 4.35 (95% CI 3.67–5.15), while the risk difference was 0.016 (95% CI 0.013–0.019). The HIV population attributable mortality fraction was 0.161 (95% CI 0.131–0.190). Sensitivity analyses demonstrated robustness of results. Conclusions Although 73.6% of adult PLHIV receive antiretrovirals in Nairobi, their risk of death is four-fold greater than in the uninfected, while 16.1% of all adult deaths in the city can be attributed to HIV infection. In order to further reduce HIV-associated mortality, high-burden countries may need to reach very high levels of diagnosis, treatment coverage, retention in care, and viral suppression.
Aids and Behavior | 2015
Cynthia Semá Baltazar; Roberta Horth; Celso Inguane; Isabel Sathane; Freide César; Helena Ricardo; Carlos Botão; Ângelo Augusto; Laura A. Cooley; Beverly Cummings; Henry F. Raymond; Peter W. Young
Aids and Behavior | 2015
Rassul Nalá; Beverley Cummings; Roberta Horth; Celso Inguane; Marcos Benedetti; Marcos Chissano; Isabel Sathane; Peter W. Young; Danilo da Silva; Joy Mirjahangir; Michael Grasso; H. Fisher Raymond; Willi McFarland; Tim Lane