Estimating PMTCT's Impact on Heterosexual HIV Transmission: A Mathematical Modeling Analysis.
BACKGROUND
Prevention of mother-to-child HIV transmission (PMTCT) strategies include combined short-course antiretrovirals during pregnancy (Option A), triple-drug antiretroviral treament (ART) during pregnancy and breastfeeding (Option B), or lifelong ART (Option B+). The WHO also recommends ART for HIV treatment and prevention of sexual transmission of HIV. The impact of PMTCT strategies on prevention of sexual HIV transmission of HIV is not known. We estimated the population-level impact of PMTCT interventions on heterosexual HIV transmission in southwestern Uganda and KwaZulu-Natal, South Africa, two regions with different HIV prevalence and fertility rates.


METHODS
We constructed and validated dynamic, stochastic, network-based HIV transmission models for each region. PMTCT Options A, B, and B+ were simulated over ten years under three scenarios: 1) current ART and PMTCT coverage, 2) current ART and high PMTCT coverage, and 3) high ART and PMTCT coverage. We compared adult HIV incidence after ten years of each intervention to Option A (and current ART) at current coverage.


RESULTS
At current coverage, Options B and B+ reduced heterosexual HIV incidence by about 5% and 15%, respectively, in both countries. With current ART and high PMTCT coverage, Option B+ reduced HIV incidence by 35% in Uganda and 19% in South Africa, while Option B had smaller, but meaningful, reductions. The greatest reductions in HIV incidence were achieved with high ART and PMTCT coverage. In this scenario, all PMTCT strategies yielded similar results.


CONCLUSIONS
Implementation of Options B/B+ reduces adult HIV incidence, with greater effect (relative to Option A at current levels) in Uganda than South Africa. These results are likely driven by Uganda's higher fertility rates.
Department of Medicine, University of Chicago, Chicago, Illinois, United States of America.
Aditya S
AS
Khanna
Department of Global Health, University of Washington, Seattle, Washington, United States of America; Department of Epidemiology, University of Washington, Seattle, Washington, United States of America.
Sarah T
ST
Roberts
Department of Epidemiology, University of Washington, Seattle, Washington, United States of America; Department of Geography, University of California, Santa Barbara, California, United States of America.
Susan
S
Cassels
Department of Global Health, University of Washington, Seattle, Washington, United States of America.
Roger
R
Ying
Department of Global Health, University of Washington, Seattle, Washington, United States of America; Department of Epidemiology, University of Washington, Seattle, Washington, United States of America; Department of Medicine, University of Washington, Seattle, Washington, United States of America; Department of Pediatrics, University of Washington, Seattle, Washington, United States of America.
Grace
G
John-Stewart
Department of Anthropology, University of Washington, Seattle, Washington, United States of America.
Steven M
SM
Goodreau
Department of Global Health, University of Washington, Seattle, Washington, United States of America; Department of Epidemiology, University of Washington, Seattle, Washington, United States of America; Department of Medicine, University of Washington, Seattle, Washington, United States of America.
Jared M
JM
Baeten
College of Physicians and Surgeons, Columbia University, New York, New York, United States of America.
Pamela M
PM
Murnane
Department of Global Health, University of Washington, Seattle, Washington, United States of America; Department of Epidemiology, University of Washington, Seattle, Washington, United States of America; Department of Medicine, University of Washington, Seattle, Washington, United States of America.
Connie
C
Celum
Department of Global Health, University of Washington, Seattle, Washington, United States of America; Department of Medicine, University of Washington, Seattle, Washington, United States of America; Department of Pediatrics, University of Washington, Seattle, Washington, United States of America; Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
Ruanne V
RV
Barnabas
D000293:Adolescent; D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D005260:Female; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D020010:Heterosexuality; D006801:Humans; D015994:Incidence; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D015995:Prevalence; D013019:South Africa; D014454:Uganda; D055815:Young Adult