The
expanding HIV/AIDS epidemic represents
one of the greatest threats to human health and
international development today, and strengthening
the global response is imperative. Despite recent
progress in expanding access to HIV/AIDS
treatment [1], the world
continues to severely under-invest in efforts to
fight HIV/AIDS, missing a tremendous
opportunity to change the course of the epidemic by
bringing proven treatment and prevention
interventions to scale.
Nowhere is the need for
an expanded response more apparent – and the
potential impact greater – than in efforts to
prevent the spread of new infections.
In 2005 alone,
nearly 5 million people worldwide became infected
with HIV, and today more than 40 million people are
living with HIV, more than in any previous year [2].
Although extensive studies have shown the
effectiveness of numerous strategies for preventing
the transmission of HIV [3], new
infections continue to occur at alarming rates
because proven tools are not being used.
Fewer than
one in five people at high risk for HIV have access
to effective prevention [4], and
funding for prevention programs is woefully
inadequate [5]. There is also an
urgent need to increase research funding and
accelerate the development of new technologies for
HIV prevention [6].
By bringing new and more
focused attention to prevention, the world can slow,
and ultimately reverse, the spread of HIV. An
analysis in 2002 by the World Health Organization
and UNAIDS found that expanded access to existing
prevention strategies could avert up to two-thirds
of the 45 million HIV infections projected to occur
between 2002 and 2010 [7], and a
study in early 2005 affirmed that expanded access to
these tools could stop roughly half of infections by
2020 [8]. Still more infections
could be prevented by the development and
introduction of new tools currently being evaluated,
such as topical microbicides, new treatments for
other sexually transmitted diseases, male
circumcision, female diaphragms, and the best
long-term hope, a preventive vaccine.
Expanded access to
HIV/AIDS prevention is also critical for sustaining the
important progress being made in providing
antiretroviral therapy to people living with HIV.
Unless the rate of new infections is sharply
curtailed, treatment will never be able to keep pace
with the growing need. For example, while the World
Health Organization's recent "3 by 5" campaign
sought to provide antiretroviral treatment to 3
million people by 2005, 5 million people became
newly infected this year alone.
To help accelerate
HIV
prevention access and research, the Bill & Melinda
Gates Foundation's Global Health program has
committed approximately $1.1 billion in grants for
HIV/AIDS programs since 1998 [9].
HIV/AIDS is among the priority diseases and health
conditions addressed by the foundation, which
provides support to organizations worldwide to
address health problems that cause the greatest
illness and death in developing countries, yet
receive far too little attention and resources. The
remainder of this article describes the foundation's
HIV/AIDS grantmaking priorities, which focus on two
critical areas: first, maximizing use of currently
available prevention tools and integrating them with
treatment and care; and second, accelerating
research on new prevention tools.
Maximizing available tools
A top priority for the foundation is expanding
access to proven HIV prevention strategies for those
who need them most. In Botswana, where an estimated
35% of the adult population is living with HIV
infection [10], the foundation is
partnering with the national government and Merck &
Co., Inc., to bring a comprehensive prevention and
treatment response to national scale. In India, the
foundation's $200 million Avahan initiative aims to
expand access to HIV prevention programs for the
most vulnerable populations, including sex workers,
their clients, injection drug users, and migrant
workers. Avahan works in partnership with national
and local governments and NGOs, and every month
reaches tens of thousands of people in six
high-prevalence states and along the most-traveled
highways.
The foundation's programs to expand access to
HIV
prevention are large-scale demonstration projects
designed to show what is possible and catalyze
others to provide support. Our resources, though
significant, are not great enough to solve
countries' HIV/AIDS challenges, and sustaining
access to health services must ultimately be the
primary responsibility of the public sector. For
example, the foundation's contribution of $150
million to the Global Fund to Fight AIDS,
Tuberculosis, and Malaria – which is assisting 128
countries in scaling up national responses to
HIV/AIDS and other leading infectious diseases – was
intended to help the fund get started and attract
other donors.
As HIV prevention programs are scaled up, it is
essential that they make use of the full range of
available prevention options, and that prevention
programs are closely integrated with treatment
services. The foundation is a co-convener of the
Global HIV Prevention Working Group, an
international body of HIV/AIDS experts focused on
HIV prevention analysis and advocacy. In 2004, the
Working Group released HIV Prevention in the Era
of Expanded Treatment Access, the first report
to identify the benefits and challenges to effective
prevention posed by expanding treatment access. (See
http://www.gatesfoundation.org/GlobalHealth/Pri_Diseases/HIVAIDS/HIVProgramsPartnerships/Prevention_Working_Group.htm.)
Accelerating research on
new tools
While today's tools have been proven effective,
there is no "magic bullet" for HIV prevention.
Women, in particular, need far greater options to
protect themselves from infection. The foundation
has committed substantial funds to research new
prevention technologies that could have a
substantial impact on reducing new HIV infections,
including many that could be initiated by women. The
foundation provides grants to support basic research
and clinical trials of investigational HIV
prevention technologies, some of which could be
available within the next few years:
Microbicides
Microbicides are topical gels or creams designed to
be applied to the vagina or rectum to prevent HIV
infection. The foundation has made grants to support
a variety of research and development efforts for microbicides, including support for a large-scale
efficacy trial of a leading microbicide candidate.
Herpes treatment
for HIV prevention
Like many other sexually transmitted diseases,
herpes (HSV-2) infection significantly increases the
risk of HIV transmission. The foundation is
supporting clinical research to assess whether using
the inexpensive drug acyclovir to treat
HSV-2
reduces the risk of HIV acquisition and
transmission.
Diaphragms
Most HIV infections in women are believed to occur
in the cervix and endocervix. By covering the
cervix, the female diaphragm may provide protection
against HIV infection. The foundation has provided
grants to support studies to help assess diaphragms
for HIV prevention in developing countries.
Male circumcision
Results from an initial clinical trial in South
Africa suggest that male circumcision reduces the
likelihood of female-to-male sexual HIV transmission
by 60% [11]. In order to confirm
these results, the foundation is supporting a trial
in Uganda, which is designed to determine if male
circumcision also reduces the risk of male-to-female
HIV transmission.
Pre-exposure
prophylaxis with antiretrovirals
Researchers are evaluating the drug tenofovir – a
nucleotide reverse transcriptase inhibitor currently
approved for the treatment of HIV – in high-risk,
HIV-negative individuals to prevent HIV infection. Tenofovir is administered in pill form and is long
lasting, slow to generate resistance, and has
relatively few side effects. The foundation has
provided support for international trials of
tenofovir for HIV prevention.
Vaccines
A preventive HIV vaccine represents the greatest
long-term hope for reversing the epidemic, but
research progress has been slow. The foundation has
contributed $126 million toward research on
promising approaches to HIV vaccination. In
addition, the foundation has joined with leading
research agencies and other funders to form the
Global HIV Vaccine Enterprise, a cooperative
alliance that aims to accelerate HIV vaccine
development through greater collaboration, strategic
focus, and resources. Future grantmaking by the
foundation in the vaccine field will be guided by
the priorities identified in the Vaccine
Enterprise's scientific strategic plan [12].
