Intended for healthcare professionals

Clinical Review Regular review

Reducing heterosexual transmission of HIV in poor countries

BMJ 2002; 324 doi: (Published 26 January 2002) Cite this as: BMJ 2002;324:207
  1. Peter R Lamptey, president, FHI AIDS Institute (Plamptey{at}
  1. Family Health International, 2101 Wilson Boulevard, Suite 700, Arlington, VA 22201, USA

    The HIV/AIDS pandemic has devastated many countries, reversing national development, widening the gap between rich and poor people, and pushing already stigmatised groups closer to the margins of society.1 It has killed millions of people, decimated families and communities, and adversely affected the lives of hundreds of millions. AIDS stands to kill more than half the young adults in the most severely affected countries.1

    By the end of 2001 an estimated 65 million people worldwide had been infected with HIV—25 million had died and 40 million were living with HIV or AIDS, most of whom have no access to the lifesaving drugs available in industrialised countries.1 Countries in sub-Saharan Africa and South and South East Asia are the worst affected (fig 1).

    Fig 1.
    Fig 1.

    Global distribution of adults and children living with HIV or AIDS at end of 2001

    The pandemic continues its relentless spread—about 14 000 people are infected each day. This article describes the impact on health and the economic and social impact of the HIV/AIDS pandemic in poor countries, discusses the many factors that promote the heterosexual transmission of HIV, highlights successes around the world in preventing infection, and outlines some of the challenges for the future.

    Summary points

    Almost all (95%) of new infections of HIV are in the world's poor countries

    Without access to antiretroviral drugs, most of the 40 million people currently living with HIV will die

    Heterosexual transmission is responsible for most HIV infections in poor countries

    Programmes to change behaviour and promote condoms and treatment of sexually transmitted infections are effective in preventing the spread of HIV

    Large scale prevention efforts have been successful in only a few countries, mainly because of inadequate resources and lack of international commitment

    Antiretroviral drugs reduce viral load in blood and consequently in genital fluids and may help prevent transmission of HIV and other sexually transmitted infections


    I performed searches of Medline, AIDS databases, global HIV and AIDS libraries (with particular emphasis on the UNAIDS website and its publications), the US Bureau of Census, and publications of the United Nations Development Programme. I also relied on personal experience through my work with Family Health International and the implementation of HIV/AIDS prevention and care programmes in more than 60 of the world's poorest countries.

    The impact of HIV/AIDS on populations

    The HIV and AIDS pandemic is having a devastating demographic impact. Gains in life expectancy over the past half century have been reversed (fig 2). Infant mortality and adult mortality have increased by more than 50% in some countries.1 Figure 3 shows the projected population structure of Botswana with and without the AIDS epidemic for the year 2020. The change from a normal population pyramid to a chimney shape reflects the disproportionate death rate among the young, sexually active, and productive segments of the population. As a result large numbers of young children and older adults will have to be supported by a shrinking proportion of productive adults.

    Fig 2.
    Fig 2.

    Life expectancy in some countries in sub-Saharan Africa with a high prevalence of HIV

    Fig 3.
    Fig 3.

    Projected population structure of Botswana in 2020 with and without HIV/AIDS


    Impact of HIV and AIDS

    • Gains in life expectancy have been reversed in many countries

    • Infant mortality and adult mortality have increased by more than 50% in severely affected countries

    • More than 13 million children, mostly in Africa, have lost one or both parents to AIDS

    • Loss of income, cost of treatment, and burial expenses severely deplete income of affected households

    The pandemic threatens to reverse the progress that has been made by the already fragile economies of poor countries. But the most severe economic impact is at the level of households, and affected families often become impoverished. In Ethiopia and Tanzania the average costs of basic treatment of the symptoms of AIDS and of funeral and mourning expenses amount to several times the average annual household income.2 A study in Thailand showed that agricultural output was halved in a third of rural families affected by AIDS, which also threatens their food security.1

    Heterosexual transmission of HIV

    Heterosexual intercourse is the most common mode of transmission of HIV in poor countries. In Africa slightly more than 80% of infections are acquired heterosexually, while mother to child transmission (5-15%) and transfusion of contaminated blood account for the remaining infections.3 In Latin America most infections are acquired through men having sex with men and through misuse of injected drugs, but heterosexual transmission is rising. Heterosexual contact and injection of drugs are the main modes of HIV transmission in South and South East Asia.1

    The rapid spread of HIV in poor countries has been attributed to several factors (box).1 Besides these risk factors pertaining to individuals, societal factors beyond the control of individuals are important in the transmission of HIV and other sexually transmitted infections.

    Key factors in the heterosexual transmission of HIV

    • Frequent change of sexual partners

    • Unprotected sexual intercourse

    • Presence of sexually transmitted infections and poor access to treatment

    • Lack of male circumcision

    • Social vulnerability of women and young people

    • Economic and political instability of the community

    Despite the explosive spread of HIV and AIDS, there have been several successful interventions to reduce the heterosexual spread of HIV. The mainstays of these programmes are interventions to change behaviour, improved access to condoms to reduce the risk of infection and decrease vulnerability to HIV, and the effective management of sexually transmitted infections.47

    Decreasing the risk of infection slows the epidemic

    Interventions to reduce risky behaviours are aimed at high risk sexual behaviours such as frequent change of sexual partners, unprotected sexual intercourse, sex at a young age among adolescents, and poor behaviour in seeking treatment for sexually transmitted infections. Such interventions also aim to change situations where there is a greater risk of being infected with HIV, such as circumstances that lead to coercive sex. To change their behaviour people need to have some basic knowledge of HIV and be aware of their risk for HIV infection.7 They must be taught a set of protective skills and offered access to appropriate services and products, such as condoms. They must also perceive their environment to be supportive of changing or maintaining safe behaviours.

    Interventions to change behaviour can be targeted at the general population or at high risk groups (the people who are at most risk of acquiring and transmitting HIV). Programmes for the general population are designed to improve awareness, knowledge, and attitudes, to change social norms, and to create a supportive environment. The groups at the highest risk of acquiring HIV are typically sex workers and their clients, people who are highly mobile, such as long distance truck drivers and migrant workers, and the military and police.

    Ways to reduce heterosexual transmission of HIV

    • Better recognition of the symptoms of sexually transmitted infections and improved behaviour in seeking treatment

    • Better management of sexually transmitted infections

    • Sexual abstinence or delayed onset of sex, especially in adolescents

    • Fewer sexual partners

    • Safer sex practices, including consistent, correct use of condoms

    • Supportive social environment to sustain behavioural change

    • Reduced stigma and discrimination against people with HIV

    • Promotion of male circumcision

    Among the most successful interventions are those targeted at sex workers and their clients.7 In Nairobi, Kenya, behaviour change programmes among these groups increased the percentage of sex workers who reported always using a condom from less than 5% in 1985 to more than 85% in the mid-1990s and reduced the annual incidence of HIV from 47% to about 1% over the same period.8 In Thailand and Cambodia, programmes promoting 100% use of condoms in brothels have successfully reduced HIV transmission in sex workers and their clients, as well as in the general population. 1 6 9 (Two figures showing trends in prevalence in particular groups are shown on

    Decreasing vulnerability decreases risk of infection

    Vulnerability refers to individual and societal factors that increase the risk of HIV infection. Societal factors include poverty, unemployment, illiteracy, gender inequities, cultural practices, lack of information and services, and human rights abuses.10 These factors greatly increase the vulnerability of women, young people, and other marginalised groups. For example, illiterate women with limited skills, few job opportunities, and limited access to health information and services are more likely than other women and the population as a whole to engage in unprotected sex for money, thereby increasing their vulnerability and risk of HIV infection. 11 12 Child prostitution in South East Asia and financial enticement of young girls by adult men in many countries increase vulnerability of girls to HIV.1 Interventions to address vulnerability seek to change adverse policies, social norms, and harmful cultural practices as well as to create income generation schemes and programmes for orphans and other vulnerable children. The most vulnerable population groups in many countries include adolescent girls, women, sex workers, illegal immigrants, orphans, and displaced people.

    Behaviour change interventions address two factors: what places people and communities at risk, and why they are at risk.1 Reducing the risk of HIV infection slows the epidemic. By decreasing vulnerability we can decrease the risk of infection and the impact of the epidemic. By decreasing the impact of the epidemic we can likewise reduce vulnerability to HIV and AIDS.

    Treating sexually transmitted infections reduces HIV transmission

    There are more than 300 million new cases of curable sexually transmitted infections throughout the world each year, with a global distribution that closely mirrors that of HIV. Each new infection not only increases the risk of HIV transmission but also carries the potential of other serious complications—miscarriage, stillbirths, infertility, ectopic pregnancy, and severe congenital infections.

    Epidemiological studies have shown that people with a sexually transmitted infection are more susceptible to acquiring HIV infection and that the presence of a sexually transmitted infection increases the risk of spreading HIV to an uninfected person.13 The behavioural risk factors for HIV are similar to those for sexually transmitted diseases, and HIV alters the epidemiology of some sexually transmitted infections.1416

    Treating sexually transmitted infections reduces HIV transmission

    • Worldwide more than 300 million new cases of sexually transmitted infections occur each year, mostly in poor countries

    • The global distributions of sexually transmitted infections and HIV are similar

    • Sexually transmitted infections are an important cause of ill health, especially in women and children

    • The presence of sexually transmitted infections increases the transmission of HIV

    • Effective management of sexually transmitted infections can reduce the risk of HIV infection

    In a study in Malawi, the successful treatment of men with both HIV and other sexually transmitted infections led to a threefold reduction in the concentration of HIV in semen two weeks after treatment.17 Effective management of sexually transmitted infections can reduce the risk of HIV transmission and acquisition as well as reduce the serious health, social, and economic consequences of sexually transmitted infections. In Thailand a reduction of the incidence of curable sexually transmitted infections by more than 80% in five years, through improved treatment and promotion of condom use, led to a decline in the prevalence of HIV in sex workers, their clients, and the military.9 In rural Mwanza, Tanzania, improving the case management of sexually transmitted infections through “syndromic” management (a diagnosis is made by matching a syndrome or group of easily recognised symptoms to well defined aetiologies, avoiding the need for sophisticated laboratory tests) in clinics reduced the incidence of HIV infection by 40%.1416 While the same intervention in Rakai, Uganda, had no effect on HIV transmission, it did show that in an area with a mature HIV epidemic, such as Rakai, services to manage sexually transmitted diseases need to be long term and that an important target group is adolescents. From the Rakai and Mwanza interventions we have learnt that prevention and treatment or control of sexually transmitted diseases can be very effective at reducing the incidence of HIV in areas where prevalence of these diseases is high and prevalence of HIV is low.1416

    HIV treatment promotes prevention

    An effective HIV prevention programme is one that is comprehensive and that addresses a community's prevention, care, and treatment needs. Essential components of a comprehensive programme include HIV testing and voluntary counselling, prevention of mother to child transmission, clinical care, and antiretroviral treatment (fig 4). Testing combined with voluntary counselling is an effective, pivotal strategy in HIV prevention and care for people with the virus, providing many benefits for people who test positive as well as for those who remain HIV negative.18 A randomised controlled trial in Kenya, Tanzania, and Trinidad showed that voluntary counselling and testing significantly reduced high risk sexual behaviour among individuals and couples.18

    Fig 4.
    Fig 4.

    Components of a comprehensive HIV/AIDS programme

    Key challenges for the future

    • Increasing resources for prevention and care

    • Reducing stigma and discrimination

    • Building the capacity in poor countries for an expanded and comprehensive response to the pandemic

    • Scaling up interventions

    • Improving access to care and treatment

    • Improving programmes aimed at orphans and other vulnerable children

    • Improving technologies, such as vaccines and microbicides

    Providing care and treatment enhances the efficacy of prevention programmes in several ways. Access to care and treatment helps to reduce the stigma associated with HIV infection, allows testing of more people, and may promote change in behaviour. But studies in industrialised countries have shown that there is a tendency for high risk sexual behaviour to increase when effective treatment becomes available.19 Prevention services must therefore provide ongoing counselling for people on antiretroviral drugs about the need to continue to practise safe sex.

    Embedded Image

    Hoarding in Delhi warning of the dangers of multiple sex partners


    The use of antiretroviral drugs to prevent mother to child transmission of HIV exemplifies the power of biological prevention strategies.19 Recent work in Uganda has shown that the concentration of HIV in the blood—and, by extension, in genital secretions—determines the efficiency of the sexual transmission of HIV within serodiscordant couples.19 These observations, together with extensive work with macaques, indicate that antiretroviral drugs can reduce the transmission of HIV. This has important implications: the extensive use of antiretroviral drugs in a population may reduce the sexual transmission of HIV from infected individuals to their uninfected partners, and antiretroviral drugs given (before or after exposure) at the community level can prevent the acquisition of HIV. However, no studies of antiretroviral prophylaxis in humans have yet been done, largely because of the difficulty in developing research strategies capable of proving the benefit of prophylaxis.19

    HIV treatment enhances prevention

    • Prevention programmes are more effective in the context of comprehensive HIV/AIDS services

    • Effective antiretroviral treatment reduces the risk of sexual transmission of HIV

    • However, access to antiretroviral drugs may lead to an increase in high risk behaviour


    Unprotected sex between men and women continues to fuel the HIV/AIDS pandemic in most of the world's poor countries, despite the efforts of prevention programmes. Major obstacles to controlling HIV/AIDS are the lack of adequate international and national commitment to the problem, inadequate resources, the lack of an expanded and comprehensive response to the pandemic, and the stigma attached to—and discrimination against—people living with HIV.

    The cost and limitations of current technologies—such as male and female condoms, microbicides, antiretroviral drugs, diagnostics and vaccines—also inhibit efforts to contain the spread of HIV and reduce the impact of AIDS.

    In the 14th century the Black Death, the most severe pandemic in history, ravaged Asia and Europe, leaving more than 40 million people dead and making a profound social and economic impact. Despite the impressive advances in medicine since then, HIV/AIDS is likely to surpass the Black Death as the worst pandemic ever. We urgently need an effective and safe vaccine, an affordable cure, and intensified prevention, care, and support programmes.


    • Competing interests None declared.

    • Embedded ImageTwo additional figures appear on


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