《卫生经济学》课程参考文献（WHO年度报告）：World Health Report 2004 changing history.pdf_P11-P15

1 chapter one a global emergency: a combined response This chapter outlines the current state of the global HIV/AIDS pandemic and explains why an international response is needed. It describes some of the tragic social and economic consequences of the disease, including its destructive impact on health systems. The response must embrace prevention, support, treatment and long-term care. Together, these components can effectively combat the seemingly inexorable progress of HIV/AIDS epidemics, offering the worstaffected countries and populations their best hope of survival. Comprehensive action will accelerate progress towards all the Millennium Development Goals while offering an opportunity to help strengthen health systems. THE GLOBAL SITUATION Although it has seemed a familiar enemy for the last 20 years, HIV/ AIDS is only now beginning to be seen for what it is: a unique threat to human society, whose impact will be felt for generations to come. Today, an estimated 34–46 million people are living with HIV/AIDS. Already, more than 20 million people have died from AIDS, 3 million in 2003 alone (1). Four million children have been infected since the virus fi rst appeared. Of the 5 million people who became infected with the virus in 2003, 700 000 were children, almost entirely as the result of transmission during pregnancy and childbirth, or from breastfeeding. The most explosive growth of the epidemic occurred in the mid- 1990s, especially in Africa (see Figure 1.1). In 2003, Africa was home to two-thirds of the world’s people living with HIV/AIDS, but only 11% of the world’s total population. Today, about one in 12 African adults is living with HIV/AIDS. One-fi fth of the people infected with HIV live in Asia. Globally, unprotected sexual intercourse between men and women is the predominant mode of transmission of the virus. In sub-Saharan Africa and the Caribbean, women are at least as likely as men to become infected. Other important modes of transmission include unprotected penetrative sex between men, injecting drug use, and unsafe injections and blood transfusions. In many countries, including most countries in the Americas, Asia and Europe, HIV infection is mainly concentrated in populations engaging in high-risk behaviour, such as unprotected sex (particularly in the context of commercial sex work or between men) and sharing of drug injection

2 The World Health Report 2004 a global emergency: a combined response 3 The uneven spread of HIV A brief analysis of the regional spread of the HIV/AIDS pandemic shows major differences between regions, within regions and within countries, which have important implications for prevention, care and support. The striking differences in the size of the epidemics in sub-Saharan Africa and other regions of the world have been well documented. While almost all countries in sub-Saharan Africa have been severely affected, widening variations are also emerging within the region, indicating that the consequences of the pandemic will vary substantially (10). The trends in HIV prevalence among pregnant women attending the same antenatal clinics since 1997 (see Figure 1.2) show that the epidemics in the countries of southern Africa are much larger than elsewhere in sub-Saharan Africa – and that the gaps appear to be widening. In eastern Africa HIV prevalence is now less than half that reported in southern Africa and there is evidence of a modest decline. In western Africa prevalence is now roughly one-fi fth of that in southern Africa and no rapid growth is occurring. These striking differences are supported by data from population-based surveys and research studies (see Box 1.2). A range of socioeconomic, cultural, behavioural and biological factors are responsible, such as migration, male circumcision practices and the prevalence of herpes simplex virus type 2 infection (12, 13). In most countries in Asia the epidemics tend to be concentrated in drug injecting and commercial sex networks, although Cambodia, Myanmar, Thailand and six equipment. In such situations, however, there is a persistent threat that localized epidemics will spill over into the wider population. In some countries, rapid growth of the size of the vulnerable populations – as a result of civil unrest, a rise in poverty or other social and economic factors – triggers epidemic growth and wider spread of the virus. The prolonged time lag between infection with HIV and the onset of full disease (on average 9–11 years in the absence of treatment) means that the numbers of HIVassociated tuberculosis cases, AIDS cases and deaths have only recently reached epidemic levels in many of the severely affected countries. Globally, the greatest mortality impact is on people between the ages of 20 and 40 years. Dramatic changes in life expectancy can be observed in the most affected parts of the world. The pandemic has reversed decades of gradual gains in life expectancy in sub-Saharan Africa (2). What does the global state of the pandemic mean in terms of progress towards the Millennium Development Goals? The eight goals, established following the historic Millennium Summit in New York in 2000, represent commitments by governments throughout the world to do more to reduce poverty and hunger and to tackle ill-health; specifi cally, to improve access to clean water and to reduce gender inequality, lack of education, and environmental degradation. This includes combating HIV/AIDS, and to have begun to reverse the spread of HIV by 2015. However, progress is not yet being made in many countries, and an unprecedented effort will be required in order for the worst-affected countries to make progress towards all of the Millennium Development Goals (see Box 1.1). 0 10 20 30 40 Year Number of infected adults (millions) 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 Figure 1.1 Estimated number of adults infected with HIV,by WHO region, 1980–2003 Eastern Mediterranean Western Pacific Europe Americas South-East Asia Africa AIDS adds to the caregiving burdens of women and girls, reducing their chances of pursuing education and paid work, and hence undermining Goal 3, to promote gender equity and empower women. Girls are often required to care for their sick brothers and sisters at the expense of their own education. HIV-positive women face many forms of discrimination and psychological and physical abuse. In the seven African countries with the highest adult HIV prevalence, AIDS has already produced a rise of more than 19% in infant mortality and a 36% rise in under-fi ve mortality, thereby reducing many countries’ chances of reaching Goal 4, to reduce child mortality. In Botswana, the under-fi ve mortality rate will reach 104 deaths per 1000 live births by 2005. In the absence of HIV/AIDS, the rate would have been 45 deaths per 1000 (6). The disease reduces the chances of reaching Goal 5, to reduce maternal mortality. In Rakai, Uganda, maternal mortality was found to be 1687 per 100 000 live births among HIV-positive women and 310 per 100 000 live births among HIV-negative women (7). HIV infection also directly increases the risks of developing tuberculosis, and in HIV/ AIDS-affected countries it is on the rise. In Malawi, for example, the incidence of tuberculosis HIV/AIDS epidemics are reducing the chances of achieving the Millennium Development Goals and targets for many heavily burdened countries, especially in sub-Saharan Africa. The epidemics undermine poverty reduction efforts by sapping economic growth, thus hampering efforts to reach Goal 1, to eradicate extreme poverty and hunger. They have cut annual growth rates by 2–4% per year in Africa (3). But the cumulative long-term macroeconomic effects may be much more devastating and could result in complete economic collapse in some high-burden countries. Educational opportunities recede as HIV/ AIDS cuts family incomes and forces people to spend money on medical care and funerals, thus affecting the chances of reaching Goal 2, to achieve universal primary education. For example, in Uganda, 80% of the children in HIV/AIDS-affected households in one village were removed from school because school fees could not be paid or the children’s labour was needed (4). In Zambia, the number of teachers killed by AIDS in 1998 was equivalent to twothirds of the number of teachers trained in the same year (5). Globally, HIV/AIDS is creating millions of orphans with even fewer educational opportunities. In addition to killing millions of women, HIV/ doubled between 1986 and 1994, largely because people living with HIV/AIDS are seven times more likely to develop tuberculosis than those who are not infected with the virus (8). In Uganda, HIV-infected women were more likely to develop malaria during pregnancy than HIVnegative women. The same study found that the mother-to-child HIV transmission rates were 40% among women with placental malaria compared with 15.4% for women without malaria (9). Thus the pandemic also adversely affects the chances of contending with malaria and other diseases, as part of Goal 6, to combat HIV/AIDS, malaria and other diseases. One target of Goal 7, to ensure environmental stability, is signifi cant improvement in at least 100 million slum dwellers’ lives by 2020. However, HIV/AIDS is likely to threaten many millions of them. All goals depend on Goal 8, to develop a global partnership for development. This goal links donors, governments, civil society and the private sector. HIV/AIDS is undermining progress here, for example through its decimation of countries’ skilled workforces. Providing access to essential medicines is a key target. Expanding HIV/AIDS treatment will be vital to progress. Box 1.1 The impact of HIV/AIDS on the Millennium Development Goals

4 The World Health Report 2004 a global emergency: a combined response 5 states in India have an estimated HIV prevalence among adults of more than 1%. The course of the epidemics in the two most populous countries in the world – China and India – will have a decisive infl uence on the global pandemic. In 2003 it was estimated that 840 000 people in China were living with HIV/AIDS, corresponding to 0.12% of the total adult population aged 15–49 years. About 70% of these infections are thought to have resulted from injecting drug use or faulty plasma-collection procedures; over 80% of all those infected are men. Offi cial estimates in India for 2003 put the number of people infected at 3.8–4.6 million, with considerable variation between states; there has been a modest increase in recent years. Countries in eastern Europe and central Asia are experiencing growing epidemics, driven by injecting drug use and to a lesser extent by unsafe sex among young people. In the Russian Federation, where national prevalence is estimated to be just under 1%, 80% of people living with HIV/AIDS are under 30 years of age. In western Europe, the estimated number of new infections greatly exceeds the number of deaths, largely as a result of the success of antiretroviral therapy in lowering death rates. There are, however, worrying signs of increased incidence of other sexually transmitted infections, such as syphilis and gonorrhoea, and reported increases in risk behaviours in several countries (14, 15). In the WHO Eastern Mediterranean Region it is estimated that there are around 750 000 people living with HIV/AIDS. Heterosexual sex is the main mode of transmission, accounting for nearly 55% of all reported cases. Injecting drug use has an increasing role in transmission and in the near future may become the driving force of the epidemics. A fi vefold increase in infections among injecting drug users between 1999 and 2002 was recorded. In Sudan, the most affected country in the region, heterosexual sex is the predominant mode of spread. In the Americas, the most affected area is the Caribbean, which has the secondhighest prevalence in the world after sub-Saharan Africa: overall adult prevalence rates are 2–3%. In Latin America, an estimated 1.6 million people are now infected. Most countries here have concentrated epidemics, with injecting drug use and sex between men as the predominant modes of transmission. The predominant mode of transmission in the Caribbean is heterosexual sex, often associated with commercial sex work. In Central America, prevalence rates have been growing steadily and most countries there are facing a generalized epidemic. In the United States of America, 30 000–40 000 new infections occur every year, with African-Americans and Hispanics the most affected populations. Rises in mortality, reductions in life expectancy In many countries there is evidence of a reversal of the declines in child mortality achieved during the 1990s, especially in those most severely affected by HIV/AIDS. These reversals indicate the adverse impact of HIV/AIDS on the Millennium Development Goal of reducing child mortality. Once again, however, large variations between African countries in their HIV-prevalence trends and levels of child mortality not associated with HIV will mean very different impacts in different places. It has been estimated that HIV/AIDS was the primary cause of about 8% of deaths in under-fi ves in sub-Saharan Africa in 2001 (16). In the absence of vital registration and reliable cause-of-death information, evidence on the impact of HIV infection on child mortality is limited. It is known, however, that even before the introduction of antiretroviral therapy the progression of disease among children infected with HIV in Europe and the USA was considerably slower than that observed in Africa. In western and eastern Africa the median survival time is less than two years, compared with well over fi ve years in developed countries (17). The most dramatic effect of the HIV/AIDS epidemic has been on adult mortality (18). In the worst-affected countries of eastern and southern Africa, the probability of a 15-year-old dying before reaching 60 years of age has risen sharply – from 10–30% in the mid-1980s to 30–60% at the start of the new millennium. In community-based studies in eastern Africa, mortality among adults infected with HIV was 10–20 times higher than in non-infected individuals (19). Overall, the greatest difference in mortality between infected and uninfected people is usually observed between the ages of 20 and 40 years. Women tend to die at an earlier age than men, refl ecting the fact that the rates of HIV infection typically peak among women 5–10 years earlier than they do in men. The most reliable estimates of the median survival time following infection with HIV have come from the Masaka study in Uganda (20) where the fi gure was of the order of nine years – two years less than that observed in developed-country cohort studies even before the advent of effective treatment. Vital registration systems, national censuses, demographic surveys and demographic surveillance systems have provided information on mortality trends (18). Census and survey data from Kenya, Malawi and Zimbabwe have revealed steadily rising adult 5 10 15 20 25 30 Southern Eastern Westerna Median HIV prevalence (%) 0 1997–1998 1999–2000 2001–2002 a No estimate available for 1997–1998. Figure 1.2 HIV prevalence among pregnant women attending antenatal clinics in areas of sub-Saharan Africa, 1997–2002 than the existing estimates based on antenatal surveillance. Nationally representative surveys have important advantages over antenatal surveillance, as they provide data on a wider sample of the population and especially on rural populations, which are often underrepresented in antenatal clinic surveillance systems. UNAIDS and WHO adjust data to correct for the underrepresentation of populations with lower prevalence, but this may not have been enough. Population-based surveys vary in their methodologies, sampling approaches, biological sample collection methods, HIV testing strategies, and ways to deal with ethical issues and incentives for participation. Nonresponse rates at the household and individual levels complicate the interpretation of results. In particular, absence from the household is likely to be associated with higher HIV prevaEstimating accurately the number of people living with HIV/AIDS is important for purposes of advocacy, programme planning and evaluation. The estimates for countries with generalized epidemics are based on data generated by surveillance systems that focus on pregnant women attending sentinel antenatal clinics. For countries with concentrated epidemics, the estimates are based on data on HIV prevalence in both high-risk and wider populations. Recently, several countries have conducted national population-based surveys that include HIV testing, and many more countries plan to do so in the near future. Demographic and health surveys have included HIV testing in the Dominican Republic, Kenya, Mali and Zambia. National surveys with HIV testing have also been conducted in Burundi, Niger, South Africa and Zimbabwe. HIV prevalence is generally lower in the population-based surveys lence. In general, survey-based estimates can be expected to be somewhat lower than the true prevalence. All estimates need to be critically appraised. A single method or data source will not usually provide the best estimate of HIV prevalence. The value of antenatal clinic-based surveillance lies primarily in the assessment of trends, and surveys conducted at 4–5-year intervals will help to improve estimates. Highquality population-based surveys can improve the assumptions that are used to estimate national levels of prevalence, for example assumptions related to rural adjustment and the computation of male prevalence. The results of population-based surveys point to the improvements needed in national HIV surveillance systems (11). Box 1.2 HIV estimates and population-based surveys

6 The World Health Report 2004 a global emergency: a combined response 7 mortality throughout the 1990s. In Kenya, the probability of dying between the ages of 15 and 60 years rose from 18% in the early 1990s to 48% by 2002 (see Annex Table 1). In Malawi the fi gure is now 63%; it was less than 30% in the early 1980s. In Zimbabwe, the 1997 probabilities of 50% for women and 65% for men have risen to an overall 80%. There is evidence that in Thailand and Trinidad and Tobago there have been increases in mortality, even though the prevalence of HIV infection is considerably lower in those countries than in most of Africa. In Thailand, for example, the crude mortality rate for those aged 15–49 years almost doubled from 2.8 to 5.4 per thousand between 1987 and 1996. The advent of the HIV/AIDS pandemic has reversed the gains in life expectancy made in sub-Saharan Africa, which reached a peak of 49.2 years during the late 1980s and which is projected to drop to just under 46 years in the period 2000–2005 (2) (see Figure 1.3). This turnaround is most dramatic in those severely affected countries in southern Africa that had relatively high life expectancy prior to the appearance of HIV/AIDS. In Botswana, for example, life expectancy decreased from nearly 65 years in 1985–1990 to 40 years in 2000–2005; in South Africa it is expected to drop from over 60 years to below 50 years. The United Republic of Tanzania (whose epidemic is less than half the size of that in South Africa) is likely to have experienced a decline in life expectancy from 51 to 43 years in the last 15 years. In Nigeria (where the epidemic is about half the size of that in the United Republic of Tanzania) the gradual improvements that were being made have stalled. Overall, life expectancy at birth in the African Region was 48 years in 2002; it would have been 54 years in the absence of HIV/AIDS. In the countries of southern Africa life expectancy would have been 56 years instead of 43 years (see Figure 1.4). THE DEADLY INTERACTION: HIV/AIDS AND OTHER DISEASES The interaction of HIV/AIDS with other infectious diseases is an increasing public health concern. In sub-Saharan Africa, for example, malaria, bacterial infections and tuberculosis (TB) have been identifi ed as the leading causes of HIV-related morbidity (22). HIV infection increases both the incidence and severity of clinical malaria in adults (23). In some parts of Africa, falciparum malaria and HIV infection represent the two most important health problems. The pandemic has brought about devastating changes in the epidemiology of TB, especially in Africa where about one-third of the population is infected with TB but does not necessarily have the disease (it is dormant). However, by the end of 2000 around 17 million people in Africa and 4.5 million people in south-east Asia were infected with both TB and HIV (24). A high proportion of these people can be expected to develop active TB unless they receive treatment (25), because HIV, by weakening the immune system, greatly increases the likelihood of people becoming ill with TB. In African countries with high rates of HIV infection, including those with well-organized control programmes, case-notifi cation rates of TB have risen more than fourfold since the mid-1980s, reaching more than 200 cases per 100 000 population in 2002 (25). In the USA, 16% of TB cases have been attributed to the virus. In parts of Asia and eastern Europe, the number of people coinfected with multidrugresistant TB and HIV is also likely to increase. In India, for example, where an estimated 1.7 million adults in 2000 were coinfected with TB and HIV, there is a multidrug resistance rate of up to 3% of previously untreated TB patients. THE AIDS TREATMENT GAP The situation outlined above shows the devastating effects of the virus on the health of the world’s people. But the effects are not evenly felt, and are often concentrated in the very places where treatment is least likely to be available. Overall, coverage with antiretroviral drugs is extremely low. In 2003, the estimated number of people worldwide needing treatment because they were in advanced stages of infection was nearly 6 million, although the numbers must be interpreted cautiously and the uncertainty range is large (4–8 million). In 2003, about 400 000 people received treatment. Coverage is lowest in the African Region, where the burden is highest and only an estimated 100 000 people are receiving treatment: a coverage of 2%. Some 34 countries accounted for more than 90% of the number of adults in need of treatment in 2003. South Africa accounts for almost one in six people in need of treatment. Half of the global treatment needs are located in just seven countries: India and six countries in the WHO African Region. 0 10 20 30 40 50 60 70 Figure 1.3 Trends in life expectancy in sub-Saharan rends in life expectancy in sub-Saharan Africa and selected countries, 1970–2010 1970–75 1975–80 1980–85 1985–90 1990–95 1995–00 2000–05 2005–10 Year Life expectancy at birth (years) All sub-Saharan Africa Botswana Nigeria South Africa United Republic of Tanzania Source: (21). Central Africa Life expectancy at birth (years) Western Africa Eastern Africa Southern Africa WHO African Region 60 50 40 30 20 10 0 Figure 1.4 Life expectancy in Africa, with and without HIV/AIDS, 2002 Without HIV/AIDS With HIV/AIDS

8 The World Health Report 2004 a global emergency: a combined response 9 THE HUMAN, SOCIAL AND ECONOMIC CONSEQUENCES Epidemics of disease are like famines, wars and natural catastrophes in one major respect: they invariably bring further disasters in their wake. Globally, HIV/AIDS epidemics are already having a disastrous domino effect. Millions of children are orphaned, communities are destroyed, health services are overwhelmed, entire countries face hunger and economic ruin. The disease affects the poor most severely: they are the most vulnerable to infection, and the poorest families are hardest hit by the suffering, illness and death caused by the disease. The effects include devastating fi nancial hardships that lead in turn to further tragic consequences. The disease forces poor families deeper into poverty, and it also condemns households that were relatively wealthy to a similar fate. Large-scale negative changes to patterns of economic and social behaviour are likely to result from the epidemic’s impact on population structure and adult life expectancy (26). Beyond the loss of income and the diversion of income to health expenditures, families resort to various “coping” strategies with negative long-term effects, including migration (27), child labour, sale of assets and spending of savings. Families suffering from the illness or death of one or more of their members experience both the direct costs of medical and funeral expenditures and the indirect costs of the impact of the illness on productivity (28, 29). HIV/AIDS is changing the very structure of populations. There are increased dependency ratios in many African countries, for example, with smaller numbers of working-age adults on whom both children and elderly relatives depend; a situation that is becoming more severe. The psychological effects on young people of seeing their immediate elders dying in huge numbers at such young ages, and consequent fears for their own future, are immense and will have profound effects on economic development. Moreover, as parents (most of them young adults) die prematurely, they fail to hand on assets and skills to their children. In this way, HIV/AIDS weakens the process through which human capital – people’s experience, skill and knowledge – is accumulated and transmitted across generations (30). The crisis of children having lost either or both parents to HIV/AIDS has been af- fl icting Africa for a decade, and will get worse. Today there are about 14 million such children in the world of whom the vast majority are in Africa, but the projected total number will nearly double to 25 million by 2010 (31, 32), a nation of children equal to the total population of Iraq. At that point, anywhere from 15% to 25% of the children in a dozen sub-Saharan countries will be orphans. Even in countries where HIV prevalence has stabilized or fallen, such as Uganda, the numbers of orphans will continue to rise as parents already infected continue to die from the disease. When orphans were relatively few, they could be cared for by extended families, but the numbers are now too great and many children end up living on the street. Women: unequally at risk Women in many countries are already facing severe hardships resulting from inequality, discrimination and victimization, and HIV/AIDS often exacerbates the hardships. In fact, these very factors help explain why women suffer disproportionately from the disease. About 58% of all people living with HIV/AIDS in the WHO African Region are women. They are infected at younger ages than men by, on average, 6–8 years. Young women are often forced into unequal sexual relationships and are frequently unable to negotiate safer sex. The unequal losses of life among women resulting from this situation will create an imbalance in the adult population, with consequences that are unknown. One likely and ominous outcome, however, is that mature men will seek younger and younger women as partners, which in turn intensifi es some of the risk factors for HIV spread. The underestimated economic threat In many countries, the cumulative effects of the epidemics could have catastrophic consequences for long-term economic growth and seriously damage the prospects for poverty reduction. Until recently, most experts believed that a generalized HIV/AIDS epidemic at 10% adult prevalence would reduce economic growth by about 0.5% per year (33). Several country-based studies have suggested that HIV/AIDS epidemics result in a reduction in gross domestic product (GDP) of around 1%, but recent economic studies and estimates suggest a much bleaker picture of current and future economic effects (30, 34). While being treated for tuberculosis at Ngwelezane Hospital, KwaZuluNatal, South Africa, Samkelisiwe Mkhwanazi was diagnosed with HIV/ AIDS. After leaving hospital she stayed for three months with a traditional healer and was treated with herbal medicines, but her condition did not improve. Samkelisiwe, 30 years old, would normally be responsible for taking care of her child and her mother, Nesta, but now she has become dependent on her mother again. “I want to be with her until I die,” she says. The entire family relies on Nesta, who must look after everyone, including Samkelisiwe’s late sister’s children (see Nesta’s story in Chapter 5). Samkelisiwe is just one of approximately 6 million people in developing countries who need urgent treatment with antiretroviral drugs. With health care systems that are unable to cope, most people living with HIV/AIDS must rely on their family or community for care. Gideon Mendel/Network A daughter’s story