Good immune restitution but unsatisfactory viral suppression in children on ART in a remote Western Kenya area

Mexico AIDS Conference 200

Viral load testing cascade for HIV infected children on non-nucleoside reverse transcriptase inhibitor-based first line regimen at selected health facilities in western Kenya

Background: Viral load (VL) testing is critical in monitoring response to HIV treatment for children.Objectives: To describe access to VL testing and testing outcomes for children on Nevirapine or Efavirenz based first line antiretroviral treatment  (ART).Design: Retrospective cohort studySetting: HIV clinics. Participants: Children aged 6 weeks to 14 years.Main outcome measures: VL test results, viral suppression, Methods: We reviewed records of children initiated on ART between 2010 and 2014. Clinic attendance within 90 days was considered active. Virological failure was defined as VL>1000copies/ml while repeat VL>1000c/ml qualified for regimen switch. Analysis used Stata Version 13.1 and Cox proportional hazard ratio was used to explore the association between outcome measures and sociodemographic at p≤0.05 level of significanceResults: Of 3,432 eligible children, 69.1% had VL results and 69.5% achieved viral suppression. Of 3,118 active on ART, 73.1% had VL results and 70.1% achieved viral suppression compared to 314 attritions from care with 29.5% and 55.4% respectively (P<0.001). Fewer children on ART < 24 months had VL results compared to those on ART for longer, 52.1% vs 76.1% (p<0.001). Probability of virological failure was higher for males and duration on ART of > 24 months but lower for age 2 – 10 years and CD4 >500 cells/mm3 compared to age < 2 years and CD4 <350 cells/mm3 respectively. Of 809 (30%) children with virological failure, 81.1% had repeat VL results of whom 72.0% had VL >1000 copies/ml and 58.9% had regimen switch. Of the 809, 308 (38.1%) switched regimen without repeat VL results and 79.9% had follow up VL >1000 copies/ml.Conclusion: Although most children achieved viral suppression, gaps in access to timely VL testing remain a challenge. Children aged >24 months and those switched without repeat VL results need additional support to achieve viral suppression

Modelling local and global effects on the risk of contracting Tuberculosis using stochastic Markov-chain models

For some diseases, the transmission of infection can cause spatial clustering of disease cases. This clustering has an impact on how one estimates the rate of the spread of the disease and on the design of control strategies. It is, however, difficult to assess such clustering, (local effects on transmission), using traditional statistical methods. A stochastic Markov-chain model that takes into account possible local or more dispersed global effects on the risk of contracting disease is introduced in the context of the transmission dynamics of tuberculosis. The model is used to analyse TB notifications collected in the Asembo and Gem Divisions of Nyanza Province in western Kenya by the Kenya Ministry of Health/National Leprosy and Tuberculosis Program and the Centers for Disease Control and Prevention. The model shows evidence of a pronounced local effect that is significantly greater than the global effect. We discuss a number of variations of the model which identify how this local effect depends on factors such as age and gender. Zoning/clustering of villages is used to identify the influence that zone size has on the model's ability to distinguish local and global effects. An important possible use of the model is in the design of a community randomised trial where geographical clusters of people are divided into two groups and the effectiveness of an intervention policy is assessed by applying it to one group but not the other. Here the model can be used to take the effect of case clustering into consideration in calculating the minimum difference in an outcome variable (e.g. disease prevalence) that can be detected with statistical significance. It thereby gauges the potential effectiveness of such a trial. Such a possible application is illustrated with the given time/spatial TB data set. (C) 2009 Elsevier Inc. All rights reserved