Dr Richard Hunt

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VIROLOGY - CHAPTER  SEVEN    

PART FIVE

HUMAN IMMUNODEFICIENCY VIRUS AND AIDS  

STATISTICS

Leading causes of death worldwide WHO

Figure 9

AIDS is currently defined in persons older than 13 years as the presence of one of 25 conditions indicative of severe immunosuppression or HIV infection in an individual with a CD4⁺ cell count of less than 200 cells per cubic mm of blood. AIDS is the end point of an infection that is continuous, progressive and pathogenic. With the prevalence of HIV in the developing world, HIV and its complications will be with us for many generations to come. AIDS is now a leading cause of death worldwide (figure 9).

There are about 33.2 million (estimate range: 30.6 million - 36.1 million) HIV-infected people in the world of whom about 22.5 million (range: 20.9 million - 24.3 million) are in sub-Saharan Africa where the adult infection prevalence is 5.9%.

Approximately 14,000 new HIV infections occur daily around the world and over 90% of these are in developing countries. One thousand are in children less than 15 years of age. Of adult infections, 40% are in women and 15% in individuals of 15-25 years of age. Perinatal infection is now resulting in a large number of children being born with HIV. 30-50% of mother to child transmissions of HIV results from breast feeding and about a quarter of babies born to HIV-infected mothers are themselves infected.

  Evolution of an epidemic. Estimated AIDS incidence in the US through 2000
Figure 10A

AIDS Cases by Age and Sex, Reported 1981-1998, United States  CDC
Figure 10B

Estimated Number of Adults and Adolescents Living with AIDS, by Sex, 1993 - 2001, United States. CDC
Figure 10C
 

United States Statistics from Centers for Disease Control

Total number of cases

As of December 2005, 984,155 Americans had been reported with AIDS (up from 641,086 in 1996). Adult and adolescent AIDS cases total 943,525 with 761,723 cases in males and 181,802 cases in females (figure 10B). Through the same time period, 9,101 AIDS cases were estimated in children under age 13.

At least  550,394 infected Americans have died of AIDS (2005 numbers). Of these, 525,442 were adults or adolescents and 4,865 were children under 13. In the early years of the epidemic, AIDS incidence increased by 65-95% each year but partly as a result of prevention efforts targeting those at highest risk, the rate of increase fell to less than 5% per year by the mid 1990's. This was prior to the introduction of combination therapies for HIV.  In 1996, estimated AIDS incidence dropped for the first time, declining 6%. Deaths among people with AIDS also declined for the first time in 1996, dropping 25% (Figure 10A) (More information)

New cases

The number of new HIV infections in the United States has fallen in recent years as has the number of cases of AIDS disease. The fall in the number of people with overt disease results from the use of anti-retroviral drugs. At the end of 2003, CDC reported an estimated 1,039,000 to 1,185,000 persons in the United States were living with HIV/AIDS (up from 242,000 in 1996), with 24 - 27% undiagnosed and unaware of their HIV infection (figure 10C). The number of people living with AIDS, that is the disease, in 2005 was 433,760 of whom 418,084 were adults and adolescents and 3,787 were children under 13.

Note: As more and more people survive with an HIV infection because of successful chemotherapeutic intervention, the number of infectious people in the population is rising even though fewer people are dying of AIDS (figure 10C). Thus, if declines in AIDS deaths continue, there will also be an increase in HIV prevalence, pointing to an increased need for both prevention and treatment services.

MORE US STATISTICAL INFORMATION

AIDS CASES BY AGE AND ETHNICITY IN THE UNITED STATES

Estimated number of AIDS related deaths worldwide 1980-2000  WHO

Mother to child transmission of HIV 1979-1999 by breast-feeding or other cause   WHO 

  HIV prevalence among pregnant women in South African provinces 1990-97

  HIV prevalence rate among teenagers in Kisumu, Kenya, by age  UNAIDS
 

HIV prevalence rate among women in their teens and twenties, various African studies 1995-98 UNAIDS

Changes in life expectancy in selected African countries with high HIV prevalence, 1950-2000 UNAIDS

Go here for more data on AIDS and HIV prevalence   UNAIDS  (PowerPoint)

Figure 11

World Statistics from The World Health Organization and UNAIDS

HIV infections have leveled off in the west and the wave of infections threatening to affect western heterosexuals has not materialized. However, this is not the case elsewhere and there have been huge increases in southern Asia and southern Africa.   

Africa

In sub-Saharan Africa, there are an estimated 22.5 million (range: 20.9 million–24.3 million; 2007 figures]) people infected by HIV with over 2.8 million new infections in 2006. In this region, there were 2.1 million deaths (figure 11 and 12). Ten million young Africans between the ages of 15 and 24 and 3 million children are infected.  Young African women are more likely to be infected with HIV than young men. According to UNAIDS, 61% of HIV-infected people in sub-Saharan Africa are female and the gap is increasing. This is in contrast to the rest of the world where more men than women are infected. Women are being infected with HIV at an earlier age than men in most countries in sub-Saharan Africa. The differences in infection levels are most pronounced among young people (aged 15 – 24 years) with, on average, 36 young women living with HIV for every 10 young men in sub-Saharan Africa.

AIDS is responsible for a decrease in life expectancy and increase in child mortality (figure 11). Child mortality rates in East Africa will double by 2010 and adult life expectancy has already declined by 2 years in that region. 

The overall infection rate for adults in sub-Saharan Africa in 2006 was 5.9% but several countries in sub-Saharan Africa report infection rates of over 30% in urban areas. In some Kenyan and Zambian towns, 1 in 5  girls is HIV-positive by the age of 20. In men over 25, the percentage who are HIV-infected can be as high as 40%. In Botswana, the proportion of the adult population living with HIV has more than doubled over the last five years, with 43% of pregnant women testing HIV-positive in 1997 in the major urban center of Francistown. (For further statistics see figure 13).

Asia-Pacific

In 2006, about 1 million people in the Asia/Pacific region became infected by HIV and 630,000 people died. The total infected population in this region is an estimated 4.9 million (range 3.7 million - 6.7 million] people; of these, 2.1 million are age 15 to 24 years and 2.4 million are women (up 21% since 2004). In this region, HIV is increasing at a rate of 10% per year. In India, the infection rate is under 1% but this means that there were 5.1 million infected people which puts India behind only South Africa in total number of cases. Much of the Indian epidemic of HIV infection results from intravenous drug use.

China also has a severe problem with up to 1.5 million HIV-infected people in 2004 (prevalence rate: 0.1%). It is predicted that if nothing is done to prevent the increasing infection rate, China will have 10 million cases by 2010.

Access to treatment in low to middle income countries

According the the WHO, just 1.6 million HIV-infected people were receiving anti-retroviral drugs in 2006. Although this is four times the number in 2003, it still represents a minority of patients who need the drugs.

It is likely that other factors than the presence of HIV influence the course of the disease but there is no strong evidence that there is any other specific infecting agent than HIV in AIDS (Please see appendix for further details).

  

HIV infection statistics by continent
Figure 12A

Global and sub-Saharan Africa AIDS Epidemic
Figure 12B

Spread of HIV infections in South Africa 1986-2001
(animated)

Spread of HIV infections in South America 1986-2001
(animated)

WEB RESOURCES

For the latest (November 2007) WHO statistics go here

UNAIDS fact sheet 2007
Key Facts
PDF

Explanation of revised 2007 estimates
PDF

UNAIDS

HIV prevalence in adults in sub-Saharan Africa, 1986-2001

PART I HUMAN IMMUNODEFICIENCY VIRUS AND AIDS

PART II HIV AND AIDS, THE DISEASE

PART III COURSE OF THE DISEASE

PART IV COFACTORS

PART V STATISTICS

PART VI  SUBTYPES AND CO-RECEPTORS

PART VII  COMPONENTS AND LIFE CYCLE OF HIV

PART VIII  LATENCY OF HIV

PART IX GENOME OF HIV

PART X  LOSS OF CD4 CELLS

PART XI  OTHER CELLS INFECTED BY HIV AND POPULATION POLYMORPHISM

APPENDIX I  ANTI-HIV VACCINES

APPENDIX II  DOES HIV CAUSE AIDS?

APPENDIX III  ANTI-HIV CHEMOTHERAPY