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HIV/Aids Statistics


 

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Acknowledgement

References


Understanding HIV/AIDS Statistics

HIV prevalence

Is the estimated percentage of the adult population living with HIV at a specific time, regardless of when infection occurred. [1]It describes the HIV trends in terms of time, place (province) and age. National level prevalence surveys are usually conducted using pregnant women attending antenatal clinics as the sample population. [2]However, they can be conducted amongst a sample of the general population (for example, as was done in the Nelson Mandela/HSRC Survey), but also in workplaces, in specific communities, or amongst particular populations (for example sex workers, or truck drivers).

Prevalence is expressed as a percentage of a particular population – for example, “20% of women attending public sector antenatal clinics were HIV positive”.

HIV Incidence

Is the number of new infections occurring over a given time period among previously uninfected people. This is usually expressed as a number of a particular population – for example, it is estimated that there are 600 new infections occurring per day.

Measuring new infections is a complex process and is usually estimated rather than being measured directly.

Estimates are usually derived from antenatal prevalence surveys, by estimating incidence using prevalence rates amongst young people (eg. 15-19 year olds) as it is more likely that any infections in this group will have occurred quite recently. Although there are limitations to this approach, changes in HIV prevalence amongst younger age groups may reflect important new trends in the epidemic.[3]

Confidence Interval

The term “95% confidence interval (CI)” is often used in HIV prevalence and behavioural surveys. Confidence intervals show how precise an estimate is. For example, the HIV prevalence of 15-19 year olds might be estimated to be 13% – but we need to know how precise that estimate is. What the 95% CI shows is the level of confidence that is influenced by the number of observations of HIV infection – so for example, the sample size might have been too small to make a very accurate estimate, and what is then given is the likely range of the estimate. In the case of the example, the researchers would say that they believe that the rate is 13%, but because of the limitations of their sample, this might range from 10% to 16%, with a 95% likelihood that it is 13.

Narrower CI ranges indicate a higher level of sampling efficiency – so a CI range of 12%-14% is better than a range of 10%-16%, in the case of our example.

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HIV/AIDS Globally

UNAIDS/WHO annually publish their AIDS Epidemic Update[4] prior to World AIDS Day. This report provides an overview of global and regional HIV/AIDS trends, and highlights key issues confronting the global community in addressing the epidemic.

The HIV/AIDS estimates published by UNAIDS/WHO are based upon the most recent available data on the spread of HIV in countries around the world. The estimates provided by UNAIDS/WHO are provisional and cannot be compared with previous estimates or those that may be published subsequently. This is owing to the fact that UNAIDS/WHO estimates may be adjusted as a result of improved knowledge of the epidemic and methods in deriving the estimates.

UNAIDS bi-annually publishes a report on the Global HIV/AIDS Epidemic. This report provides an overview on the state of the HIV/AIDS epidemic and provides and overview of the responses to the epidemic[5].

Global Summary of HIV/AIDS, December 2002 [6]

Number of People living with HIV/AIDS Total
Adults
Women
Children under 15
42 million
38.6 million
19.2 million
3.2 million
People newly infected with HIV 2002 Total
Adults
Women
Children under 15
5 million
4.2 million
2 million
800 000
AIDS Deaths 2002 Total
Adults
Women
Children under 15
3.1 million
2.5 million
1.2 million
610 000
Source: UNAIDS AIDS Epidemic Update, December 2002

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Sub-Saharan Africa

The HIV/AIDS epidemic in Sub-Saharan Africa is a development issue. Without access to life prolonging treatment, the epidemic will negatively impact on all sectors of society.

The economic impact of AIDS includes costs to both corporations and individual households and communities. Cost to workplaces include increasing numbers of staff falling ill, the need to replace and train new staff members; costs associated with reduced productivity owing to the attendance of funerals, caring for their friends and families living with HIV/AIDS. However the greatest economic cost will be felt at the household and community level where increasing amounts of personal income will be expended on health, care and support and funerals. These costs can only be covered through diverting expenditure away from core resources.

HIV/AIDS will impact negatively on food production as an increasing number of people become too sick, too poor or too overburdened to provide for themselves and their families. The United Nations warns that HIV/AIDS threatens to destabilise countries across the region by undermining social services, weakening communities and an increasing orphan population.

Across the continent a number of countries are mounting programmes to address the impact of the HIV/AIDS epidemic. These include programmes prevention aimed at preventing new infections, care and support for those living with HIV/AIDS, emphasising home-based care and positive living and increasingly the provision of treatment to those in need in countries such as Uganda, Botswana and Nigeria.

Such programme are undertaken in partnership between governments, multilateral development agencies such as the United Nations and its specialised agencies, bilateral donors, international and local NGOs.

Summary of HIV/AIDS in Sub-Saharan Africa

Adults and Children living with HIV with HIV/AIDS, end 2002

Youth aged 15 – 24 living with HIV
% of young women living with HIV

29.4 million


10 million
6 – 11%

% of young men living with HIV

Children under 15 living with HIV

3 – 6%

3 million

Adults and children newly infected with HIV/AIDS during 2002 3.5 million
Africans in need of treatment

Africans currently receiving treatment

4.1 million

50 000

Deaths owing to HIV/AIDS 2002 2.4 million
Adult Prevalence Rates 8.8%
Main Mode of Transmission Heterosexual
Source: UNAIDS AIDS Epidemic Update, December 2002; UNAIDS Global Report of the HIV/AIDS Epidemic, 2002; WHO. 2003. Global AIDS treatment emergency. http://www.who.int/mediacentre/factsheets/2003/fs274/en/

The table below summarises the HIV prevalence rates amongst adults aged 15 – 49 at the end of 2001 in Southern Africa.

Country HIV Prevalence amongst adults 15-49 end 2001
Angola 5.5
Botswana 38.8
Lesotho 31
Malawi 15
Mozambique 13
Namibia 22.5
South Africa 20.1
Swaziland 33.4
Tanzania 7.8
Zambia 21.5
Zimbabwe 33.7
Source: UNAIDS. 2002. Report on the Global HIV/AIDS Epidemic. Geneva. UNAIDS

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HIV/AIDS in South Africa

Antenatal Clinic Surveys (ANC)

Antenatal Clinic Survey (ANCs) have been undertaken in South Africa since 1990. This survey comprises an anonymous, unlinked survey among pregnant women attending antenatal care at selected sites in all nine provinces of the country. The data derived from the ANC provides an estimate of HIV prevalence amongst pregnant women attending public sector antenatal clinics. These prevalence levels provide us with a picture of the HIV epidemic over time.

The graph below shows the trends in HIV infection amongst women attending ante-natal clinics in South Africa since 1990.

Figure 2: HIV prevalence trends among antenatal clinic attendees in South Africa, 1990 - 2002


Source: Department of Health, 2003. National HIV and Syphilis Antenatal Sero-Prevalence Survey in South Africa: 2002

Estimates for HIV prevalence amongst the total population are derived from antenatal data through the use of assumptions and mathematical modelling[7].

The ANCs have limitations in estimating national prevalence as they are limited to currently or sexually active pregnant women of a limited age group (15-49) do not include men and excludes women utilizing private medical services in South Africa[8].

Summary of Key Findings from the ANC’s 2002


Source: Department of Health, 2003. National HIV and Syphilis Antenatal Sero-Prevalence Survey in South Africa: 2002

Nelson Mandela / HSRC Study of HIV/AIDS: South African National HIV Prevalence, Behavioural Risks and Mass Media Household Survey 2002

This survey was conducted for the first time in 2002 by the Human Sciences Research Council (HSRC), Medical Research Council (MRC), Centre for AIDS Development Research and Evaluation (CADRE) and ANRS.

The survey sampled people living in households and hostels throughout South Africa and provides detailed information on HIV infection rates by age, race, sex, province and locality-type as well as information on knowledge, attitudes and behaviours[9].

Estimates for the entire population are based on applying findings to the census. The wide confidence intervals indicate that in some cases the sample sizes were quite small. The Actuarial Society of South Africa[10] cautioned that this may have resulted in bias in relation to prevalence rates relating to province, race and amongst children aged 2-14.

Summary of key findings from the Nelson Mandela / HSRC study of AIDS


Source: Nelson Mandela/HSRC Study of HIV/AIDS: South African National HIV Prevalence, Behavioural Risks and Mass Media, Household Survey 2002

Actuarial Society of South Africa: AIDS 2000 AIDS and Demographic Model

The Actuarial Society of South Africa (ASSA) is a voluntary association of actuaries working in the field of HIV/AIDS. The ASSA AIDS Model 2000 is one in a series of epidemiological models developed by ASSA since 1996. This model enables predictions to be made of the impact of the epidemic at both the national and regional level through calibrating to reproduce past antenatal clinic survey data and the number of adult deaths recorded by the Department of Health on the population register (adjusted for an estimate for under-recording). As such the models represent the triangulation of data from the census, antenatal survey and registered deaths by some of the country's top actuaries, demographers and epidemiologists. The model provides data according to two scenarios one in which there is no change and another which takes into change factors into account[11].

Summary of key data from the ASSA 2000 AIDS and Demographic Model

Source: www.assa.org.za/aidsmodel.html

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Reporting Tips

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Acknowledgements

Sarah Bennett, Actuarial Society of South Africa (ASSA) AIDS Committee and NMG Levy

Dominic Liber, Actuarial Society of South Africa (ASSA) AIDS Committee and Quindiem Consulting.

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Contacts

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References

1 UNAIDS & WHO. 2002. AIDS Epidemic Update: December 2002. UNAIDS. Geneva.
2 Department of Health, 2003. National HIV and Syphilis Antenatal Sero-prevalence Survey in South Africa: 2002.
3 UNAIDS & WHO. 2002. AIDS Epidemic Update: December 2002. UNAIDS. Geneva.
4 UNAIDS & WHO. 2002. AIDS Epidemic Update: December 2002. UNAIDS. Geneva
5 UNAIDS. 2002. Report on the Global HIV/AIDS Epidemic 2002. UNAIDS. Geneva.
6 UNAIDS & WHO. 2002. AIDS Epidemic Update: December 2002. UNAIDS. Geneva.
7 Department of Health, 2003. National HIV and Syphilis Antenatal Sero-prevalence Survey in South Africa: 2002.
8 Department of Health, 2003. National HIV and Syphilis Antenatal Sero-prevalence Survey in South Africa: 2002.
9 Shisana, et al. 2002. Nelson Mandela / HSRC Study of HIV/AIDS: South African National HIV Prevalence, Behavioural Risks and Mass Media, Household Survey 2002. Human Sciences Research Council. Cape Town.
10 Actuarial Society of South Africa. 2003. Contrary Finding to HSRC. In: AIDS Analysis Africa
11 Actuarial Society of South Africa, http://www.assa.org.za/aidsmodel.html, Accessed: October 2003.

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