HIV Prevention is
Michael H. Merson, MD
Epidemiology and Public Health
Yale University School
60 College Street
New Haven, CT 06511
Estimates at the end
of 1997 indicate that, since the start of the pandemic, approximately 42
million adults and children had been infected with HIV and 11.7 million of
them had developed AIDS. Ninety percent of all infections have occurred in
developing countries. ' Despite these daunting numbers and the well-known
fact that it is difficult to change well established behaviors, there is
increasing evidence, worldwide, that AIDS prevention is possible.
In planning our
prevention interventions, it must be borne in mind that HIV infection is a
classical, sexually-transmitted disease. Worldwide, half of all infections
are in youth 15-24 years of age and the average age of infections declines
as the epidemic becomes more established in a country, reflecting the entry
of newly, sexually active persons into the population. Transmission of the
virus is more efficient from men to women than from women to men. However,
like other sexually transmitted diseases, HIV can be spread parenterally
(through blood) and perinatally (from mother to child). While the percent of
infections transmitted parenterally through injecting drug use worldwide is
relatively small (around 10%), this route is responsible for half of all new
HIV infections in the United States and has been the major means of
introduction of HIV into all Asian countries that now have a major epidemic,
as well some countries in South America. Most perinatal infections occur in
Sub-Saharan Africa and other under served areas where heterosexual
transmission is common. While antiretroviral therapy is highly effective in
reducing transmission from mother to child, there is little or no access to
these drugs in many developing countries.
As the vast majority
of HIV infections worldwide are sexually transmitted, international HIV
prevention efforts have placed greatest emphasis on interrupting this means
of transmission. In almost all settings, heterosexual transmission is the
predominant mode of sexual spread. The main approach to prevention of sexual
transmission has been the promotion of safer sex messages through a wide
variety of channels along with the provision of condoms. When properly
manufactured, stored and used, condoms are virtually 100% effective in
preventing HIV transmission, as best evidenced in studies of discordant
couples (when one member of a couple is positive). ' In many countries
educational interventions have been successful in increasing safer sex
practices, including in high-risk populations, such as men who have sex with
men, commercial sex workers and their clients, truck drivers, factory
workers and the military. Many of these projects have been undertaken by
community-based organizations who deliver safer-sex messages and provide
Because of the
increasing rates of infections in youth and the declining age of first
intercourse, prevention efforts have frequently been undertaken in schools.
The most effective sex education programs in schools have emphasized
abstinence from sex for those who have not been sexually active and prefer
to remain so and use of condoms for those who are sexually active. Some
schools make condoms available through health educators. Such programs have
been successful in increasing condom use and reducing pregnancy rates and
rates of new sexually transmitted diseases (STDs) without increasing sexual
Another type of
effective prevention intervention has been condom social marketing programs.
These programs use modem marketing techniques to promote and sell condoms at
a low price to high-risk populations using multiple channels. They seek to
make condoms popular and to decrease any inhibitions associated with their
use. Condom sales in 37 developing countries with social marketing
assistance from USA organizations increased from 20,000 sold in 1987 to 530
million sold in 1997. In Switzerland a national condom social marketing
program directed at adolescents and young adults has been credited with
slowing the epidemic in that country.
One other type of
preventive intervention has been voluntary testing and counseling programs.
These programs were originally used primarily to detect HIV-infected blood
donors, but have become commonly used by those wishing to know if they were
infected. They have been found to be effective in bringing about safer sex
practices, when counseling is done effectively and both partners of a couple
are tested and counseled. This is especially the case for discordant
Beginning in the late
1980's, there has been acceptance that educational efforts directed toward
safer sex behavior should be accompanied by more effective treatment of
sexually transmitted diseases. This is because genital ulcer disease
increases the risk of HIV transmission per sexual exposure 10 to 50 times
for male to female transmission and 50 to 3 00 times for female to male
transmission. ' Non-ulcerative STD)s (chalmydia and gonorrhea) similarly
increase the risk two to five-fold. A recently conducted study in Tanzania
demonstrated a 42% reduction in new HIV infections after two years of
follow-up as a result of improved STD care.' This included training of
primary health care workers in STD syndromic case management, making
available effective antibiotics and promoting health care seeking behavior
by those infected. The positive impact of comprehensive STD case management
and targeted condom promotion has been demonstrated in a number of
clinic-based and community settings in Africa and Asia, particularly in high
risk populations. The greatest challenge in using this approach is to find
means for identifying the 30-50% of women who have asymptomatic STDs,
particularly those with chlamydia infection.
behavioral and STD treatment interventions are directed toward individuals.
Interventions that change laws, policies or administrative procedures
(structural interventions) or alter living conditions, resources,
opportunities or social preserves (environmental interventions), and thus
are directed toward societal change, are also effective in preventing sexual
transmission. One of the most effective of these has been the 100% condom
use policy in brothels in Thailand! This intervention, which has brought
about nearly universal condom use in brothels, has been responsible for the
dramatic decline in HIV and STD infections in that country between 1990 and
1995. Other similar type of interventions include the removal of import
taxes on condoms (to decrease their price) and the education of women so
that they need not be sex workers to earn income.
Transmission Through Injecting Drug Use
Most the experience
in programs to reduce HIV transmission among injecting drug users (IDUs) has
been in developed nations. The most effective programs are based on the
principle of harm reduction, i.e., reducing the risk of HIV infection in
these injecting drugs. Such programs also reduce the incidence of other
parenterally transmitted infections, particularly hepatitis. One type has
been community outreach programs, which involve the recruitment of outreach
workers who seek out IDUs and provide them education on safe injection
practices, bleach to disinfect injection equipment, and condoms, while
offering them access to voluntary and counseling services and drug
treatment. These programs have been particularly effective in providing
services for hard-to-reach drug users. ' A second type of program is
syringe- exchange. These programs exchange dirty needles and syringes for
clean ones and provide preventive messages and access to health care and
drug treatment. Their effectiveness in reducing HIV transmission without
increasing drug use has been clearly demonstrated. ` A third type of
effective intervention (which is a structural intervention) is the making of
clean needles and syringes readily available to IDUs through pharmacies or
vending machines. This allows IDUs to obtain injection equipment in a more
anonymous manner and has been shown to decrease needle sharing and purchase
of needles and syringes on the street. I'
To achieve their
maximum impact, all three types of interventions should be carried out
simultaneously in order to give IDUs options for prevention. Simultaneously,
drug treatment, particularly methadone maintenance programs, should be
established and sufficient opportunities made available for those needing
treatment. The federal government has recently proposed that methadone be
made available in physician offices, not only in special clinics, in order
to expand access to the drug.
How to Achieve
There are increasing
numbers of countries that have mounted successful prevention efforts.'
Countries like Thailand, Uganda, Tanzania, Zambia, Senegal and Switzerland
have implemented programs that have decreased sexual transmission. So have
gay men in this country. Countries like Australia and New Zealand have
illustrated the achievements possible through harm reduction programs in
decreasing transmission through injection drug use.
One reason why these
countries have been successful is that they have formulated prevention
policies on the basis of sound science. This has enabled them to combat the
many myths that have characterized this pandemic. This includes the myth of
complacency ("we won't / don't have the problem), the myth that condoms are
not effective, that sex education in schools leads to youth having more sex,
that syringe exchange programs increase drug use, that sexual behavior
cannot be changed and that we need to wait for a vaccine before I-HV will be
prevented (a vaccine will help, but all experts agree that it is at least a
decade away). Overcoming some of these myths is often not easy, even in the
presence of solid scientific data, because they are based on moral beliefs
and teachings. Indeed, HIV prevention is "counter-cultural" in that it
requires that we discuss sexuality openly, admit that adolescents have sex,
recognize sexual diversity and delink condom use to distrust of one's
programs have also combated the discrimination and stigmatization often
associated with HIV and AIDS. Because AIDS is contagious, disfiguring and
presumed to be fatal, it elicits fears about our own mortality. Society may
respond to these fears by stigmatizing those infected with HIV and
populations with high rates of infection. Such stigmatization and the
resulting discrimination are particularly difficult for populations that are
already stigmatized, such as gay men, drug users, commercial sex workers
and, in this country, communities of color, which because of their increased
vulnerability, have high rates of HIV infection. Successful programs have
also resisted efforts, often generated by discriminatory policies, to try
and prevent HIV infection through mandatory testing and quarantine which can
never be effective in controlling this disease.
To overcome the myths
of AIDS and combat discrimination requires strong political leadership from
government, the private (business) sector, and leaders in other sectors of
society (including from sports, entertainment, academia and religion).
Countries that have achieved successful prevention have had such leadership.
They also have encouraged "grass root" action by community based groups,
including persons infected and affected by HIV who often are the best
carriers of prevention messages.
Perhaps the greatest
challenge now facing HIV prevention has been the advent of new and improved
anti-retroviral therapy. The new combination therapy has been shown to have
the potential to greatly prolong the life of HIV-infected persons and to
markedly improve the quality of their lives. However, it is making HIV
prevention more difficult, as it gives the impression that there is a "cure"
for AIDS, thereby discouraging the need to practice safer sexual behavior.
This situation is made even more dangerous by the increasing prevalence of
HIV strains resistant to these drugs due to poor adherence or intolerance to
the drug therapy. Because of these concerns, it is essential that health
care providers emphasize the importance of prevention when administering
anti-retroviral drugs and that the media and pharmaceutical industry not
exaggerate the benefits of this therapy.
Throughout the world
religious leaders have played an important role in AIDS care. In particular,
they have provided much needed support and compassion for HIV-infected
persons and have spoken out against the stigmatization and discrimination
HIV-infected persons frequently face in their daily lives. Church leaders
need to continue to help safeguard the rights of persons affected by
HIV/AIDS and to participate actively in discussions of ethical issues posed
by the epidemic at local, national and international levels. In the United
States and elsewhere there are efforts underway to enact measures that will
limit the rights of HIV-infected persons based on the mistaken belief that
such measures can enhance prevention efforts.
participation is needed among religious leaders in addressing their
congregations about HIV prevention and in working more closely with
community-based prevention programs. This task is often difficult because of
the behaviors associated with HIV infection. Experience has shown beyond
doubt that successful prevention requires acknowledging that these behaviors
exist and addressing them in a frank, realistic and non-judgmental manner.
Gay men, commercial sex workers and injecting drug users are often rejected
by society, yet they are among those most vulnerable to HIV infections.
Churches should help to educate these populations as to how to prevent HIV
infection, and to develop locally relevant responses. Similarly, churches
should have special programs to inform youths about how HIV infection is
transmitted and how to protect themselves. They should also work with women
as they seek to attain equality with men socially and economically, since
this equality is essential to reduce their vulnerability to HIV infection.
communities need to feel empowered to cope with the challenges of the
epidemic. They need to believe that they are not rejected by their religious
communities. Religious leaders can thus play a key role in engendering this
empowerment so that these communities can obtain the prevention and care
services they need. In some circumstances this will require that religious
communities confront their own fears and prejudices about those populations
that are most vulnerable to MV infection. If churches can provide a climate
of love, acceptance and support for those who are vulnerable to, or affected
by, HIV and AIDS, other sectors of society are likely to follow.
on the Global HIV/AIDS Epidemic. 1997 World Health Organization:
2.De Vincenzi, 1.
(1994). A Longitudinal Study of Human Immunodeficiency Virus Transmission
by Heterosexual Partners.
New Engl J Med,
3.Merson, M., Dayton,
J., (1998). Effectiveness of HIV Prevention Interventions in Developing
4.Kirby, D., Short,
L., Collins, J., et al (1994). School-Based Programs to Reduce Sexual Risk
Behaviors: A Review of Effectiveness.
Public Health Reports,
Jeannin, A., Konings, E., et al (1997). Increased Condom Use without Other
Major Changes in Sexual Behavior among the General Population in
American Journal of
87 (4): 558 566
Schulz, K.F. & Plummer, F.A. (1995). The Cofactor Effect of Genital Ulcers on
the Per-Exposure Risk of HIV Transmission in SubSaharan Africa.
J Trop Med
Mosha, F., Todd, J. et al. (1995). Impact of improved treatment of sexually
transmitted diseases on HIV infection in rural Tanzania: Randomized
W. & Hanenberg R. (1996). The 100 percent condom program in
9.Coyle, S. L.,
Needle, R., Normand, J. (1998) Outreach-Based HIV Prevention for Injecting Drug
Users: A Review of Published Outcome Data.
Public Health Reports, 113(l):19-30.
10.Vlahov, D. & Junge,
B. (1998). The Role of Needle Exchange Programs in HIV Prevention.
Public Health Reports, 113(l):75-80.
Weinstein, B., Jones, T.S., et al. (1995). Impact of Increased
Legal Access to Needles and Syringes on Practices of Injecting-Drug Users
and Police Officers-Connecticut, 1992-1993. Journal of Acquired
Immune Deficiency and Human Retro virology, 10:82-89.