NIH-sponsored
trial suggests home-based HIV testing and referral to care works at
population level
NIH/NATIONAL
INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
New
HIV infections declined by 30 percent in southern African communities
where health workers conducted house-to-house voluntary HIV testing,
referred people who tested positive to begin HIV treatment according
to local guidelines, and offered other proven HIV prevention measures
to those who tested negative. Local guidelines evolved during the
study from offering HIV treatment based on immune health to offering
immediate treatment for all.
Surprisingly,
the investigators found that new HIV infections did not decline in
communities where those who tested positive were offered immediate
treatment throughout the study. Analyses are under way to try to
explain this puzzling outcome.
These
results from the large clinical trial called «Population Effects
of Antiretroviral Therapy to Reduce HIV Transmission» (PopART),
or HPTN 071, were announced today at the Conference on Retroviruses
and Opportunistic Infections (CROI) in Seattle. The findings also
will be presented Wednesday as an oral abstract at the conference.
«The
results of the PopART study suggest that conducting population-wide,
home-based HIV testing and offering treatment to those diagnosed with
HIV could help control the epidemic in certain settings,» said
Anthony S. Fauci, M.D., director of the National Institute of Allergy
and Infectious Diseases (NIAID), part of the National Institutes of
Health. «These findings indicate that a universal test-and-treat
strategy could be an important addition to our toolbox of proven HIV
prevention modalities.»
The
goal of PopART was to learn whether conducting HIV testing throughout
a population and promptly offering treatment to all who test positive
would achieve a high level of community-wide HIV suppression, thereby
reducing the rate of new infections in the population.
NIAID
sponsored and co-funded PopART, which was funded primarily by the
U.S. President’s Emergency Plan for AIDS Relief (PEPFAR),
administered by the Office of the U.S. Global AIDS Coordinator and
Health Diplomacy in the U.S. Department of State. Leading the study
were Richard Hayes, M.Sc., D.Sc., F.Med.Sci., professor of
epidemiology and international health at the London School of Hygiene
& Tropical Medicine; and Sarah J. Fidler, M.B.B.S., Ph.D.,
professor of HIV medicine at Imperial College London.
The
PopART study took place from 2013 to 2018 in 21 urban and peri-urban
communities in South Africa and Zambia. Each community had an average
of roughly 50,000 residents for a total study population of about 1
million. The communities were clustered into seven groups of
three–«triplets»–matched by geographical location and
estimated HIV prevalence. The communities in each triplet were
assigned at random to one of three study groups. The first group
received annual house-to-house voluntary HIV testing and counseling,
linkage to care for those who tested positive and the opportunity to
immediately begin treatment, and the offer of a suite of proven HIV
prevention measures to those who tested negative. The second group
received the same services as the first, except treatment was offered
according to national guidelines. The third group served as a control
and received HIV prevention and testing services according to the
local standard of care as well as HIV treatment according to national
guidelines.
At
the beginning of the trial, the national guidelines for HIV treatment
in Zambia and South Africa specified that people living with HIV
should start antiretroviral therapy (ART) when their CD4+ T cell
count–a measure of immune health–had declined to 350 cells per
microliter. That threshold was raised to 500 cells/μL
in 2014. Then in 2016, the countries recommended that everyone
diagnosed with HIV begin ART immediately, regardless of CD4+ T-cell
count. Consequently, the first and second groups of communities in
the PopART study received the same intervention during the last two
years of the trial.
To
measure the impact of the PopART interventions, the investigators
recruited a random sample of 48,300 adults ages 18 to 44 years from
the overall study population, including roughly 2,300 adults from
each community. Members of the study team visited these participants,
called the «population cohort,» at the start of the trial
and then once a year for three years to collect data through a
questionnaire and blood testing, including a test for HIV infection.
Between
the first and third years of the study, 553 new HIV infections
occurred in the population cohort during nearly 40,000 person-years
of follow up for an incidence rate of 1.4 infections per 100
person-years (p-y). Investigators found that HIV incidence was 7
percent lower in group 1 than in the control group (1.5/100 p-y
versus 1.6/100 p-y), but this difference was not statistically
significant. In contrast, investigators found that HIV incidence was
30 percent lower in group 2 than in the control group (1.1/100 p-y
versus 1.6/100 p-y), and this difference was highly statistically
significant and consistent across all seven matched triplets.
Among
those members of the population cohort who tested positive for HIV by
the second year of the study, the investigators determined the
proportion who had an undetectable level of virus in their blood.
Viral suppression was achieved by 72 percent of these study
participants in group 1, 68 percent in group 2 and 60 percent in the
control group.
«We
found very strong evidence of an effect in the group that received
treatment according to national guidelines, said Dr. Hayes. «The
absence of a clear reduction in HIV incidence in the group that
received the most intensive HIV prevention intervention is surprising
and inconsistent with the group’s rate of viral suppression. Further
analyses of qualitative and quantitative data from the study
communities may help us better understand this unexpected result.»
The
study data include information on mobility and migration as well as
findings from an ongoing study of the genetic evolution of
circulating HIV strains in the study population.
«The
HPTN 071 (PopART) study, the largest HIV prevention study conducted
to date, highlights the importance of conducting large-scale studies
that aim to measure the impact of an integrated prevention strategy,»
said Wafaa El-Sadr, M.D., M.P.H., M.P.A. Dr. El -Sadr is co-principal
investigator of the NIH-funded HIV Prevention Trials Network (HPTN)
and professor of epidemiology and medicine at Columbia University.
«Achieving HIV epidemic control will require the integration of
various evidence-based interventions tailored to the needs of
specific populations,» she added.
The
PopART study was conducted by HPTN investigators in collaboration
with the London School of Hygiene & Tropical Medicine, Imperial
College London, the Zambia AIDS-Related Tuberculosis Project and the
Desmond Tutu TB Centre of South Africa. HIV care and treatment were
provided by government health services in the study communities with
support from PEPFAR under the direction of the U.S. Agency for
International Development and the U.S. Centers for Disease Control
and Prevention.
In
addition to PEPFAR and NIAID, study funders included the
International Initiative for Impact Evaluation with support from the
Bill & Melinda Gates Foundation, as well as the National
Institute on Drug Abuse and the National Institute of Mental Health,
both part of NIH.
###
For
more information about the PopART clinical trial, please search
ClinicalTrials.gov using study identifier NCT01900977.
This
study was supported by NIAID grants UM1AI068613-07, UM1AI068617-07
and UM1AI068619-07.
Reference: R
Hayes et
al.
Impact
of universal testing and treatment in Zambia and South Africa: HPTN
071 (PopART). Oral presentation at the Conference on Retroviruses and
Opportunistic Infections (CROI), Seattle. Presented March 6, 2019.
NIAID
conducts and supports research–at NIH, throughout the United States,
and worldwide–to study the causes of infectious and immune-mediated
diseases, and to develop better means of preventing, diagnosing and
treating these illnesses. News releases, fact sheets and other
NIAID-related materials are available on the NIAID
website.
About
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Services. NIH is the primary federal agency conducting and supporting
basic, clinical, and translational medical research, and is
investigating the causes, treatments, and cures for both common and
rare diseases. For more information about NIH and its programs,
visit http://www.nih.gov.
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