HIV Prevention Efforts Have
Curbed the U.S. AIDS Epidemic: Scientific Analysis Estimates the Overall
Benefit to Society
ATLANTA -- If not for HIV prevention efforts, it is likely that the
number of additional individuals infected with HIV in the United States
would be equivalent to the population of a moderate-sized to large city,
according to research conducted by David Holtgrave, PhD, from Emory
University's Center for AIDS Research.
The research, published in
the Nov. 22, 2002 edition of AIDS: The Official Journal of the International
AIDS Society, is significant because it begins to answer two of the
most frequently asked questions related to the AIDS epidemic in the
United States: (1) roughly how many individual lives may have been saved
because of our nation's investment in HIV prevention since the onset
of the epidemic and (2) have these HIV prevention efforts ultimately
resulted in cost-savings to society?
"It is impossible to count
exactly how many HIV infections would have occurred if efforts to prevent
the spread of the virus had never been put in place," said Dr. Holtgrave,
professor of behavioral science and health education in the Rollins
School of Public Health. "However, we can do the next best thing and
explore through statistical modeling the course the U.S.. epidemic might
have followed without HIV prevention programs."
To accomplish this, Dr. Holtgrave
began by charting the HIV incidence patterns (or yearly patterns of
new HIV cases) in order to highlight the incidence curve (or the point
at which new HIV cases begin to level off). To gauge the effectiveness
of HIV prevention, one would have to compare the HIV incidence curve,
as experienced, with the HIV incidence curve that would have occurred
had there been no HIV prevention activities. The area between these
two curves would then represent the number of HIV infections prevented.
The challenge researchers have had in developing even general estimates
of effectiveness of HIV prevention efforts is that no one can say for
certain how high the U.S. incidence curve would have gotten without
HIV prevention efforts, before naturally decreasing and eventually leveling
off..
Dr. Holtgrave's research
utilized scenario analysis to estimate where the incidence curve could
have leveled off under a wide range of plausible possibilities, and
then assessed (a) the order of magnitude of the number of HIV infections
prevented in the U.S. from 1978 to 2000; and (b) whether national HIV
prevention efforts could generally be considered cost-effective.
Under four conservative scenarios
regarding the course the AIDS epidemic might have taken had there been
no prevention efforts in place, it is estimated that our nation's investment
in HIV prevention has averted at least 204,000 and as many as 1.585
million HIV infections (see attachment below for specific details).
If the actual number of infections prevented were 204,000 (the bottom
of the range), it is estimated that the cost per infection prevented
would be a little under $50,000, which is less than the lifetime medical
cost of treating an individual with AIDS (approximately $154,000 to
$195,000 currently; and approximately $56,000 before advanced HIV/AIDS
treatment regimens).
If the actual number of infections
prevented were closer to the top of the range, at 1,585,000, then it
is estimated that the cost per infection prevented would be around $6,400,
which is only a small fraction of the cost of treating an individual
with AIDS. "Either way," said Dr. Holtgrave, "although limited by multiple
sources of uncertainty, the findings indicate a strong likelihood that
HIV prevention efforts to date in the United States have literally saved
hundreds of thousands of Americans, and have resulted in significant
cost savings to society."
"Another way of stating these
results," he added, " is that each of the 204,000 to 1.5 million HIV
infections that were prevented saved society $56,000 to $195,000 in
averted medical costs -- or a total of at least $11 billion saved. These
analyses do not include other real benefits of prevented HIV infections
such as increased worker productivity and decreased pain and suffering."
Background Information -
Estimating the effectiveness and efficiency of U.S. HIV prevention efforts
using scenario and cost-effectiveness analysis
Scenario and cost-effectiveness
analyses were used to estimate the effectiveness and efficiency of HIV
prevention activities in the United States from 1978 until 2000. Under
four conservative scenarios (see below) on the course the AIDS epidemic
might have taken had there been no prevention efforts, the findings
estimate that prevention activities averted between 204,000 and 1,585,000
HIV infections at a cost of between $49,700.00 and $6,400.00 per infection
prevented.
Description of Scenarios
Scenario/Descrip./Approx.
HIV Infections Averted/Net Cost Per Infect. Averted/Gross Cost Per Infec.
Averted 1 / Stayed flat after peak at 161,000 infects. a yr. / 1,585,000
/ $6,400 / Cost-Saving
2 / Declined (after peak),
then flattened at 123,000 infects. a yr. /1,031,000/$9,800/Cost-Saving
3 / Declined (after peak)
at 6.2% per yr. / 672,000 / $15,100 / Cost-Saving
4 /Decl. (after peak) at
12.4% per yr. until flat at 40,000 infect. yr./204,000/$49,700/Cost-Saving
Description of HIV Prevention
Budget
Up to and including fiscal
year 2000, the federal Centers for Disease Control and Prevention (CDC)
had a budget for HIV prevention of approximately $7.2 billion (summed
over all years as raw dollar figures). However, this is not the entire
national contribution to HIV prevention; other federal, state and private
contributions must be added. We estimated that an additional 8.1% was
spent on other federal programs, another 27% on state-funded efforts,
and a further 5.6% from private sources. (There is uncertainty as these
additional percentages were based on limited data available for a short
time period and extrapolated across the time frame of the epidemic;
further, since these figures are budgetary, the true costs of the programs
may have been more or less than budgeted.) Including all of these sources
of funding, the estimated expenditure on HIV prevention programs in
the United States through fiscal year 2000 is $10.1 billion. |