Demographic and socioeconomic impact of AIDS

Introduction Six years have passed since AIDS published a supplement on the demographic impact of AIDS [1]. That volume reviewed the evidence of the impact of AIDS on mortality and fertility in the early and mid-1990s. Community studies showed increases in adult and child mortality and a fertility reduction among HIV-infected individuals; demographic and health surveys and national censuses showed substantial increases in adult mortality in several countries, and models showed the large effects of AIDS on mortality and moderate impacts on population growth. Since 1998, a large amount of new evidence has become available from specialist community-based studies, national surveys and censuses. Various analytical techniques have been developed that allow us to use these data in new ways. In addition to demographers and epidemiologists, social scientists and economists are now starting to look at empirical evidence on the effects of HIV, at the family, community and national level. Although modelling was the primary basis for an assessment of the size and future of the epidemic in the past, increasingly use is made of real data to inform policy and to evaluate national responses to the epidemic. In this context it is timely and appropriate to re-visit this problem area, to summarize our wider knowledge of the demographic and social impacts of the epidemic, and to broaden the range of effects that we scrutinize critically to include macro and micro-economic impacts. These impacts of AIDS are having an increased impact on policy making: the health services are stretched; the education system is losing teachers; and numbers of orphans are growing. Policy needs to be advised by good data and rigorous analysis. A scientific meeting on the Demographic and Socioeconomic Impact of AIDS was held in Durban, South Africa, on 26–28 March 2003, and forms the basis for the reviews in this supplement. Most evidence of the impact of the epidemic presented here relates to sub-Saharan Africa. With an estimated 26.6 million HIV infections out of the global total estimate of 40 million by end-2003, and with an adult HIV prevalence at least 10 times higher than in most other parts of the world [2], it is clear that the magnitude of the impact in sub-Saharan Africa on the population and economies is bound to be of a different scale. Also within Africa there are huge and widening differences in the spread of HIV, which implies that the consequences of the epidemic will differ substantially, irrespective of differences in non-AIDS conditions [3]. HIV prevalence among pregnant women in southern Africa is as much as five times higher than in western Africa and three times higher than in eastern Africa. Adult mortality The most dramatic impact of the HIV epidemic is on adult mortality. In the worst affected countries of eastern and southern Africa, the probability of a 15-year old dying before reaching the age of 60 years has risen dramatically, from a range of 10 to 30% in the mid-1980s, to a range of 30–60% at the turn of the century [4]. Two of the review papers in this volume focus on the topic of adult mortality. The first, by Porter and Zaba [5] examines the direct evidence furnished by community-based studies in which the serological status of individuals is measured, allowing comparisons to be made between the mortality of infected and uninfected individuals. The second, by Blacker [6], looks at the indirect evidence afforded by national level statistics, in which serostatus is unknown, but time trends and age patterns strongly suggest a major impact of the HIV epidemic. In five community-based studies in eastern Africa, mortality in HIV-infected adults was between 10 and 20 times higher than in uninfected individuals after standardizing for age. There is a characteristic age pattern in the relationship between mortality rates for infected and uninfected individuals, so that the maximum impact is usually observed between the ages of 20 and 40 years, earlier for women and later for men, a reflection of typical age patterns of incidence, which peak 5–10 years earlier for women. Porter and Zaba [5] examine a variety of methods for calculating the population-attributable fraction of mortality to obtain estimates of how much lower overall mortality would be without HIV-related deaths from a variety of data sources. In the seven studies reviewed, crude adult prevalence ranged from 4 to 16%, attributable mortality ranged from 24 to 74%, generally the population-attributable fraction is approximately six times prevalence, the exact relationship depending on epidemic maturity and background mortality level. A few developing country cohort studies have furnished evidence about mortality by duration since infection; the most reliable estimates come from the Masaka study [7], and suggest that median survival time post-infection is of the order of 9 years, approximately 2 years less than observed survival in developed country cohort studies before the advent of effective antiretroviral therapy. Blacker [6] reviews the usefulness of sources such as vital registration systems, national censuses, demographic surveys and demographic surveillance systems for furnishing information on adult mortality trends in the context of the HIV epidemic. He provides an incisive discussion of the weaknesses of each source when it comes to furnishing concrete proof of the impact of AIDS, and describes some useful methods for adjusting and correcting estimates on the basis of these data. Census and survey data from Kenya, Malawi and Zimbabwe showed rising adult mortality in the 1990s: in Kenya the probability of dying between the ages of 15 and 60 years (45q15) increased from 18% in the early 1990s to 28% by the end of the decade; in Malawi it is now over 45%, having been below 30% in the early 1980s; in Zimbabwe by 1997 45q15 was 50% in women and 65% in men. In Zimbabwe, these results are confirmed by trends in mortality rates based on vital registration, after making allowances for improved coverage of the death registration system. Registration data in Thailand and Trinidad also furnish evidence for mortality increases, even though HIV prevalence is considerably lower than in most of Africa. In Thailand, the crude mortality rate for young adults (aged 15–49 years) increased from 2.8 to 5.4 per thousand between 1987 and 1996; in Trinidad AIDS has become the leading cause of death in the 15–44 year age group. Given the imperfections in the data sources and the periodic nature of censuses and large-scale population surveys, the general population mortality impacts of HIV only become apparent some 10 years or more after HIV prevalence reaches significant levels. Indirect evidence of mortality impact should be sought primarily in those age groups (20–40 years), which the direct studies have identified as having the most disparate mortality rates between infected and uninfected and a high prevalence of infection. Child mortality Since the beginning of the HIV pandemic, nearly four million children under 15 years of age worldwide have been infected with HIV, and in the year 2003 alone an estimated 700 000 children were newly infected [2], nearly always through mother-to-child transmission, which can occur before, during and after delivery, including breastfeeding. In the absence of vital registration and reliable cause of death information, evidence on the impact of HIV infection on child mortality is limited to data from either relatively small hospital-based studies or to more extensive population-based data that have been manipulated with specific assumptions to arrive at estimated rates of child mortality caused by HIV/AIDS. The review by Newell et al. [8] focuses on survival among HIV-infected children, factors affecting survival among HIV-infected children, survival among children of HIV-infected mothers compared with children of HIV-negative mothers, and child mortality trends and estimates from population-based surveys. Before the introduction of antiretroviral therapy, the progression of disease among HIV-infected children in Europe and the USA was considerably slower than that observed in a few studies in Africa. Data from the studies in west and east Africa indicate that the median survival time is below 2 years of age compared with well over 5 years of age in industrialized country studies. There is increasing evidence that the survival time of children is affected by the stage of infection of the mother, maternal survival, the use of antiretroviral therapy, background mortality levels and possibly the timing of infection. Currently, there is no consistent evidence that children who acquire infection in utero or intrapartum have a higher mortality rate than those who become infected through breastfeeding. Data from population-based longitudinal studies with HIV testing of adults in Malawi, Tanzania and Uganda permit an assessment of child mortality among children of HIV-positive mothers. Allowing for geographical and temporal differences in background levels of mortality, for the child's sex and for the mother's age, children born to HIV-infected mothers were estimated to be three times more likely to die than children born to uninfected mothers, with the effect lasting throughout the first 5 years of childhood. The results also indicate that having a dead or dying HIV-negative mother is associated with similar adverse consequences to having a healthy HIV-infected mother. Trend data for child mortality are available for many countries from vital registration, census, or more recently, household surveys. In many countries there is evidence of a reversal of the child mortality decline during the 1990s, especially in some of the more severely AIDS-affected countries, and modelling indicates that AIDS is a significant contributor to the changes in many countries. There are, however, large differences between African countries, and both disparate trends in HIV prevalence and varying levels of non-HIV-associated child mortality will ensure very different impacts in different countries. It has been estimated that HIV/AIDS was the primary cause of approximately 10% of under-five deaths in sub-Saharan Africa in 2003 [9]. Fertility In a review of six community studies, it was concluded in 1998 that in societies with low contraceptive use, HIV-infected women have at least 25% lower fertility than HIV-uninfected women, except for the youngest age group in which selection for early sexual activity results in higher fertility for the HIV infected. Lewis et al. [11] examined new evidence from 19 community studies on the estimates of the fertility rate ratio and population-attributable change in total fertility, and concluded that the earlier estimates are still valid. A few studies contributed multiple observations over time, which is of particular interest for the assessment of biases associated with the mainstay of HIV surveillance in generalized epidemics: monitoring trends among women attending antenatal clinics. No clear patterns of change in the association between fertility and HIV over time have emerged. The direct fertility impact of the AIDS epidemic at the population level is small but not negligible if the epidemic is severe. Lewis et al. [11] concluded that a 1% change in HIV prevalence is associated with a population-attributable change of 0.37% in total fertility, and also showed that Uganda had 6% fewer births during the past two decades because of AIDS. Little is known about the fertility behaviour of the much larger HIV-negative population in the era of AIDS. National surveys do not reveal any association between fertility intentions and the stage of the epidemic. It is clear, however, that better data are needed. Population and family structure The impact of the AIDS epidemic on adult mortality may affect the welfare of affected families and social institutions. Heuveline [12] considered such compositional changes, changes in the age structure of the population or in the composition of households, which may ultimately have far-reaching social and economic consequences. Changes in the population age–sex structure have hitherto been limited to specific age groups, and no dramatic changes have occurred in most countries. Focusing on the most severely affected parts of Africa, Heuveline [12] found that demographic and social processes have diffused the impact of the epidemic throughout the entire population and spread it over all households. Limited evidence of the impact of the epidemic has to but overall family systems of the most affected have been there are good to and the monitoring of and affected by the epidemic, as the is likely to increases in adult mortality, even if to antiretroviral increases National household surveys are an large-scale monitoring and data from 40 national surveys in sub-Saharan Africa to the impact of AIDS on the prevalence of and to children under 15 years of age in the 40 countries, nearly of the had at least and 1% had both The prevalence of increased during the 1990s in countries more severely affected by HIV/AIDS. In a child is very irrespective of the survival status of the most orphans to with a family most with the if not with the The surveys some evidence for the association between education and among of estimates of impact estimates are the most source of information on the size and impact of the AIDS epidemic. of are usually because of the of the available data. The of an and HIV has the of HIV The of evidence on the association between AIDS, adult and child mortality and an assessment of the of demographic and et al. compared the ratio of mortality among HIV-positive and HIV-negative the of all adult deaths attributable to AIDS, and the of orphans between studies in countries with generalized with estimates published by The differences between the demographic from the two sources are generally within the range of or which was by for the In other these results are and indicate that the demographic estimates based on surveillance data and demographic models are and for and it is to that there is a range the in including population-based surveys with HIV testing and the of antenatal surveillance the population will to the of the of the estimates by better estimates of HIV the other it is not likely that more data will become available to the of survival time to antiretroviral is likely to the the mortality impact of the epidemic. Socioeconomic impact of AIDS is on presented at a that both the demographic and impact of AIDS. The of the and papers on family family and household empirical evidence of impacts in the and empirical evidence for impact in the the papers 19 were about the impact of the disease on welfare or in some the impact was the seven review papers in the volume do not include on The of this will there are no economic and reviews in the It will also some of the more information on the effects of the HIV epidemic and some on the HIV/AIDS usually adults at the peak of years and for significant of time before pattern of mortality is well in the demographic of the supplement. an economic it is at the level of individuals and that the epidemic has most significant a large of are as in many countries in sub-Saharan Africa and some countries in and the the economic impact of HIV/AIDS to the particular economic and entire national In economic the macro is made of the each and death and increased to the families and of those but it is the many of that may cause economic to There are a of empirical papers on the impact of AIDS have not been in this which include the of empirical data The first is the of data. have to censuses, vital registration data and Demographic and large national do not have this information It is to the or social will there are a of household and studies, which are the and household impact data are not in national surveys, so we are on a small of surveys, with on to other There has been a study of a national which to the impact of AIDS and it would be very to for more use to be made of data at the household level for the of and national surveys. It is not to such information to HIV but it at least be to it to information on household of mortality and It is very to look at the impact because most of the consequences of increased adult and mortality have not been alone in many countries will not be for many The nature of the disease that and death between and 10 years after and the consequences will in the years after In many African countries HIV prevalence is still There is evidence from Uganda to that the prevalence of HIV to decline in the early 1990s, the of orphans in the country was still increasing in that if HIV prevalence is peak the of orphans will for many more years, and the social of with this will to is in and vital such as births and and that is also in at AIDS. individuals with or by AIDS the of to and may be as as the deaths and for among it is to for early or death and than for of are likely to be by among and mortality are the of impacts on families and and in the on national are better at mortality than of problem for economists and is that in some we may be to that is not The worst affected and if a survey is out at a household level the that have will be in this volume that AIDS deaths are associated with an in household and child Although the children will generally end in survey to the new household may not on the that to the of the children, because these occurred in of this at the national level is that we that AIDS and the of some parts of the world as has of direct but how do that has not come to a The of In at the impact of and death on and economies the problem is that not all are, in economic world economies may more and that there will be fewer and less to on however, deaths not affect the of the at the level and in economic the be better The of the of is to be very as is who will the and how will on this be These are but as economists may have an Most that look at the impacts of AIDS similar the impact on households, the effects on health and education because this is the limited data are the and A of review and have this than through the here we will some of the presented at the and or that have since The with the most empirical evidence on impact from the for at of the source of two The first on the of HIV/AIDS to showed that AIDS is to an Six in South Africa and and data and out HIV surveys. The estimated the of HIV infections with a median survival and real HIV prevalence in the ranged from to It was estimated that HIV/AIDS among to the and and among levels within depending on the levels and of HIV prevalence, and the status of The presented new data on the effect of AIDS on on a in Kenya The that there is very on because in most the health the of an can be this are by the amount each and from There is a of data on both the and the health of each The reviewed of health and over a found that during years of who as a of AIDS were from as as other Most of this of to as early as years before death for those infected with the years of individuals who were to die of HIV infection only of the the year before the to in the year of and in the The were data is on a range of education through the and a and The data on mortality in was but so only over a and it with increased mortality, the may be as a for data There is real about the impact of AIDS on the health but by and large this is There will be an increased for and as and Since the was held in March 2003, the new of the has made a that three million will be antiretroviral by by 5 The of this for the health are huge and this is an that needs data. made in the showed how is huge was the impact of AIDS on and has been to by the by the of that the huge in country in is caused by the of with AIDS The had a a million The economic impact of HIV/AIDS on is so significant because most individuals with HIV/AIDS in affected countries are and for households. the impact is because other and death to be within with two or more adults affected as on the to or The impact on is in a of different ways. is affected as are during of and as a of are affected as and to and on other of and services are and are affected as use to the of after the deaths of that orphans are usually out to family or to for and were to be and In South Africa many of the affected below the per In Kenya the death of a household is associated with a reduction in the of the much less effects were found in the of the death of other household was to was that AIDS and affected be with HIV/AIDS to relatively more on of and services than do households. In significant differences were found between on within affected and households. on were and less among and affected than were among and impact of HIV/AIDS on is that it to in household and and increases in after the from as a of or the death of a household at a variety of including and the study in found that affected approximately less than Although in the study more from and services than affected households, affected were more likely to from There is no empirical evidence for the impact of HIV/AIDS. on the likely impact of AIDS are based on models of but always economic with and without AIDS. The models have been based on two that there will be a of from the as individuals and and second, that the of these and deaths will be from that would to Most models a small impact on of the order of between and less per Although this is significant over time, at any it is very There are other on economies and which may have the models suggest that total may the impact on the per is less per may even depending on how many individuals die and the impact of this mortality on In other the may be but the of individuals among it is will be even a effect that is generally not because of and major with models is that have not The most to the of the epidemic is the The that the economic of AIDS are to be very much higher than those to and may even be the of in an when to South Africa of economic in three is the on the demographic and economic impact of AIDS that the of this have in The first was in That meeting in two the demographers the supplement to AIDS to at the beginning of this [1]. The social scientists and economists an The is to the between and years we to has been is clear, and that is that the social will have in the of empirical data that demographers are to is a reflection of the nature of the epidemic and There are those who would that we will always the impact of this disease when we economic and social can orphans and effect has on and but and impacts are much more to the in of household in families that in but it would be to the impact of the of orphans on the of other children in these or the effect of and for children in a do we a the time, the evidence of demographic evidence has during of the evidence however, by a small of longitudinal studies in sub-Saharan Africa, and there is a clear for more studies to the impact of the epidemic as it impact data will be to the impact of the AIDS epidemic through an effective