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The potential impact of expanding antiretroviral therapy and combination prevention in Vietnam: towards elimination of HIV transmission.

Kato M, Granich R, Bui DD, Tran HV, Nadol P, Jacka D, Sabin K, Suthar AB, Mesquita F, Lo YR, Williams B - J. Acquir. Immune Defic. Syndr. (2013)

Bottom Line: Annual HTC and immediate treatment for key populations, combined with scale-up of methadone maintenance therapy and condom use, will reduce new infections by 14,723 (81%) with similar costs (US $22.7 million).This combination prevention scenario will reduce the incidence to less than 1 per 100,000 in 14 years and will result in a relative cost saving after 19 years.Targeted periodic HTC and immediate ART combined with other interventions is cost-effective and could lead to potential elimination of HIV in Can Tho.

View Article: PubMed Central - PubMed

Affiliation: *World Health Organization Vietnam Country Office, Hanoi, Vietnam; †World Health Organization HIV/AIDS Department, Geneva, Switzerland; ‡Vietnam Authority of HIV/AIDS Control, Ministry of Health, Hanoi, Vietnam; §Partners in Health Research, Hanoi, Vietnam; ‖US Center for Disease Prevention and Control Vietnam Country Office, Hanoi, Vietnam; ¶World Health Organization Regional Office for the Western Pacific Manila, Philippines; and #South African Centre for Epidemiological Modelling and Analysis, Geneva, Switzerland.

ABSTRACT

Background: Few studies have assessed the effects of antiretroviral therapy (ART) to prevent HIV transmission in Asian HIV epidemics. Vietnam has a concentrated HIV epidemic with the highest prevalence among people who inject drugs. We investigated the impact of expanded HIV testing and counseling (HTC) and early ART, combined with other prevention interventions on HIV transmission.

Methods: A deterministic mathematical model was developed using HIV prevalence trends in Can Tho province, Vietnam. Scenarios included offering periodic HTC and immediate ART with and without targeting subpopulations and examining combined strategies with methadone maintenance therapy and condom use.

Results: From 2011 to 2050, maintaining current interventions will incur an estimated 18,115 new HIV infections and will cost US $22.1 million (reference scenario). Annual HTC and immediate treatment, if offered to all adults, will reduce new HIV infections by 14,513 (80%) and will cost US $76.9 million. Annual HTC and immediate treatment offered only to people who inject drugs will reduce new infections by 13,578 (75%) and will cost only US $23.6 million. Annual HTC and immediate treatment for key populations, combined with scale-up of methadone maintenance therapy and condom use, will reduce new infections by 14,723 (81%) with similar costs (US $22.7 million). This combination prevention scenario will reduce the incidence to less than 1 per 100,000 in 14 years and will result in a relative cost saving after 19 years.

Conclusions: Targeted periodic HTC and immediate ART combined with other interventions is cost-effective and could lead to potential elimination of HIV in Can Tho.

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Related in: MedlinePlus

Schematic diagram showing the links between the different subpopulations in the model. Red arrow shows HIV transmission via needle sharing, green arrow shows sexual transmission among MSM, and blue arrow shows heterosexual transmission. The groups coloured pink indicate that HIV transmission happens within the group.
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Figure 1: Schematic diagram showing the links between the different subpopulations in the model. Red arrow shows HIV transmission via needle sharing, green arrow shows sexual transmission among MSM, and blue arrow shows heterosexual transmission. The groups coloured pink indicate that HIV transmission happens within the group.

Mentions: A standard compartmental model with susceptible people, PLHIV not on ART, and PLHIV on ART24,25 was developed for each of 7 subpopulations. Although generalized epidemics are often modeled assuming 1 population with similar characteristics, concentrated epidemics require the establishment of subpopulations with different HIV prevalence, different roles in HIV transmission dynamics, and different interventions. To address this issue, a network structure that links subpopulations as seen in Vietnam was used to construct the model (Fig. 1) The model includes the following: PWID, men who have sex with men (MSM), female sex workers (FSWs), male clients of female sex workers (MCF), and low-risk women (LRW). MSM and FSWs are further divided into 2 groups: those who inject drugs and those who do not. It is assumed that a certain proportion of men in all male groups visit FSW or have regular female partners (see Appendix, Supplemental Digital Content,http://links.lww.com/QAI/A431). We also assumed that although LRW can be infected by their male sexual partners, they do not infect other adults. The low-risk men, including low-risk MSM, were excluded from the model, with the assumption that their contribution to the epidemic and studied outcomes are negligible. However, if a person in key populations ceases to be engaged in the risk behavior, but is infected with HIV, he or she was retained in the model and counted in the original risk groups. The equations and further details for the model are given in the Appendix (see Supplemental Digital Content,http://links.lww.com/QAI/A431) and are implemented in Microsoft Excel. The model is fitted using maximum likelihood, allowing for overdispersion of the data where necessary, and checking that the fit is statistically acceptable for each subpopulation separately and collectively.


The potential impact of expanding antiretroviral therapy and combination prevention in Vietnam: towards elimination of HIV transmission.

Kato M, Granich R, Bui DD, Tran HV, Nadol P, Jacka D, Sabin K, Suthar AB, Mesquita F, Lo YR, Williams B - J. Acquir. Immune Defic. Syndr. (2013)

Schematic diagram showing the links between the different subpopulations in the model. Red arrow shows HIV transmission via needle sharing, green arrow shows sexual transmission among MSM, and blue arrow shows heterosexual transmission. The groups coloured pink indicate that HIV transmission happens within the group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814627&req=5

Figure 1: Schematic diagram showing the links between the different subpopulations in the model. Red arrow shows HIV transmission via needle sharing, green arrow shows sexual transmission among MSM, and blue arrow shows heterosexual transmission. The groups coloured pink indicate that HIV transmission happens within the group.
Mentions: A standard compartmental model with susceptible people, PLHIV not on ART, and PLHIV on ART24,25 was developed for each of 7 subpopulations. Although generalized epidemics are often modeled assuming 1 population with similar characteristics, concentrated epidemics require the establishment of subpopulations with different HIV prevalence, different roles in HIV transmission dynamics, and different interventions. To address this issue, a network structure that links subpopulations as seen in Vietnam was used to construct the model (Fig. 1) The model includes the following: PWID, men who have sex with men (MSM), female sex workers (FSWs), male clients of female sex workers (MCF), and low-risk women (LRW). MSM and FSWs are further divided into 2 groups: those who inject drugs and those who do not. It is assumed that a certain proportion of men in all male groups visit FSW or have regular female partners (see Appendix, Supplemental Digital Content,http://links.lww.com/QAI/A431). We also assumed that although LRW can be infected by their male sexual partners, they do not infect other adults. The low-risk men, including low-risk MSM, were excluded from the model, with the assumption that their contribution to the epidemic and studied outcomes are negligible. However, if a person in key populations ceases to be engaged in the risk behavior, but is infected with HIV, he or she was retained in the model and counted in the original risk groups. The equations and further details for the model are given in the Appendix (see Supplemental Digital Content,http://links.lww.com/QAI/A431) and are implemented in Microsoft Excel. The model is fitted using maximum likelihood, allowing for overdispersion of the data where necessary, and checking that the fit is statistically acceptable for each subpopulation separately and collectively.

Bottom Line: Annual HTC and immediate treatment for key populations, combined with scale-up of methadone maintenance therapy and condom use, will reduce new infections by 14,723 (81%) with similar costs (US $22.7 million).This combination prevention scenario will reduce the incidence to less than 1 per 100,000 in 14 years and will result in a relative cost saving after 19 years.Targeted periodic HTC and immediate ART combined with other interventions is cost-effective and could lead to potential elimination of HIV in Can Tho.

View Article: PubMed Central - PubMed

Affiliation: *World Health Organization Vietnam Country Office, Hanoi, Vietnam; †World Health Organization HIV/AIDS Department, Geneva, Switzerland; ‡Vietnam Authority of HIV/AIDS Control, Ministry of Health, Hanoi, Vietnam; §Partners in Health Research, Hanoi, Vietnam; ‖US Center for Disease Prevention and Control Vietnam Country Office, Hanoi, Vietnam; ¶World Health Organization Regional Office for the Western Pacific Manila, Philippines; and #South African Centre for Epidemiological Modelling and Analysis, Geneva, Switzerland.

ABSTRACT

Background: Few studies have assessed the effects of antiretroviral therapy (ART) to prevent HIV transmission in Asian HIV epidemics. Vietnam has a concentrated HIV epidemic with the highest prevalence among people who inject drugs. We investigated the impact of expanded HIV testing and counseling (HTC) and early ART, combined with other prevention interventions on HIV transmission.

Methods: A deterministic mathematical model was developed using HIV prevalence trends in Can Tho province, Vietnam. Scenarios included offering periodic HTC and immediate ART with and without targeting subpopulations and examining combined strategies with methadone maintenance therapy and condom use.

Results: From 2011 to 2050, maintaining current interventions will incur an estimated 18,115 new HIV infections and will cost US $22.1 million (reference scenario). Annual HTC and immediate treatment, if offered to all adults, will reduce new HIV infections by 14,513 (80%) and will cost US $76.9 million. Annual HTC and immediate treatment offered only to people who inject drugs will reduce new infections by 13,578 (75%) and will cost only US $23.6 million. Annual HTC and immediate treatment for key populations, combined with scale-up of methadone maintenance therapy and condom use, will reduce new infections by 14,723 (81%) with similar costs (US $22.7 million). This combination prevention scenario will reduce the incidence to less than 1 per 100,000 in 14 years and will result in a relative cost saving after 19 years.

Conclusions: Targeted periodic HTC and immediate ART combined with other interventions is cost-effective and could lead to potential elimination of HIV in Can Tho.

Show MeSH
Related in: MedlinePlus