HIV Insight: Early HIV Infection

Showing posts with label Early HIV Infection. Show all posts

Thursday, April 7, 2016

Early HAART Initiation May Not Reduce Actual Reproduction Number and Prevalence of MSM Infection: Perspectives from Coupled within- and between-Host Modelling Studies of Chinese MSM Populations

Having a thorough understanding of the infectivity of HIV, time of initiating treatment and emergence of drug resistant virus variants is crucial in mitigating HIV infection. There are many challenges to evaluating the long-term effect of the Highly Active Antiretroviral Therapy (HAART) on disease transmission at the population level. We proposed an individual based model by coupling within-host dynamics and between-host dynamics and conduct stochastic simulation in the group of men who have sex with men (MSM). The mean actual reproduction number is estimated to be 3.6320 (95% confidence interval: [3.46, 3.80]) for MSM group without treatment. Stochastic simulations show that given relatively high (low) level of drug efficacy after emergence of drug resistant variants, early initiation of treatment leads to a less (greater) actual reproduction number, lower (higher) prevalence and less (more) incidences, compared to late initiation of treatment. This implies early initiation of HAART may not always lower the actual reproduction number and prevalence of infection, depending on the level of treatment efficacy after emergence of drug resistant virus variants, frequency of high-risk behaviors and etc. This finding strongly suggests early initiation of HAART should be implemented with great care especially in the settings where the effective drugs are limited. Coupling within-host dynamics with between-host dynamics can provide critical information about impact of HAART on disease transmission and thus help to assist treatment strategy design and HIV/AIDS prevention and control.

Below: Time series of susceptible and infected individuals

Below: Histogram of the number of secondary cases induced by a single infected individual in a simulation

Full article at: http://goo.gl/MHsHUH

By: Xiaodan Sun,¹ Yanni Xiao,^1,* Sanyi Tang,² Zhihang Peng,³ Jianhong Wu,⁴ and Ning Wang^5,*

Gui-Quan Sun, Editor

¹Department of Applied Mathematics, Xi’an Jiaotong University, Xi’an, Shaanxi, China

²College of Mathematics and Information Science, Shaanxi Normal University, Xi’an, Shaanxi, China

³School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China

⁴Laboratory for Industrial and Applied Mathematics, Centre for Disease Modelling, York Institute for Health Research, York University, Toronto, ON, Canada

⁵National Center for AIDS/STD Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing, China

Shanxi University, CHINA

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Tuesday, March 15, 2016

Economic & Health Implications from Earlier Detection of HIV Infection in the United Kingdom

Purpose:

To model the budget and survival impact of implementing interventions to increase the proportion of HIV infections detected early in a given UK population.

Patients and methods:

A Microsoft Excel decision model was designed to generate a set of outcomes for a defined population. Survival was modeled on the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) study extrapolated to a 5-year horizon as a constant hazard. Hazard rates were specific to age, sex, and whether detection was early or late. The primary outcomes for each year up to 5 years were: annual costs, numbers of infected cases, hospital admissions, and surviving cases. Three locations in the UK were chosen to model outcomes across a range of HIV prevalence areas: Lambeth, Southwark, and Lewisham (LSL), Greater Manchester Cluster (GMC), and Kent and Medway (K&M).

Results:

In LSL, the projected cumulative cost savings over 5 years were £3,210,206 or £5,290,206 when including the value of the 104 life-years saved. Savings were insensitive to transmission rates, but sensitive in direct proportion to the percentage shift from late to early detection. In GMC, savings were in a similar proportion to LSL, but the magnitude was smaller, as a consequence of the lower base-case HIV prevalence. In K&M, with a smaller population and lower HIV prevalence than GMC, savings were commensurately smaller (£733,202 cumulatively over 5 years).

Conclusion:

The results strengthen the rationale for implementing increased testing in high prevalence areas. However, in areas of low prevalence, it is unlikely that costs will be returned over a 5-year period.

Purchase full article at: https://goo.gl/6wGaAh

By: Vladimir Zah,^1,2 Mondher Toumi¹

¹Ecole Doctoral Interdisciplinaire Sciences-Santé (EDISS), University of Lyon, Lyon, France; ²ZRx Outcomes Research Inc., Mississauga, Canada

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