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New HIV Diagnoses, AIDS Cases And Deaths: National Overview
The cause of AIDS (Acquired Immune Deficiency Syndrome) is a virus, HIV (Human Immunodeficiency Virus) first isolated in 1983 (1).
HIV-1 and HIV-2 are the main strains that cause the majority of infections and cases of AIDS (2). HIV attacks the CD4+ lymphocytes, killing off these cells, weakening the immune system, which leads to AIDS and death if immune system severely affected (2;3).
The main transmission routes for this infection are via sexual intercourse or through contact with infected blood (4).
Epidemiology Of HIV & AIDS
The infection is now in over 200 countries and territories worldwide and is spreading rapidly in many affected populations, particularly in developing countries. A UNAIDS report estimates the HIV prevalence for the UK as a relatively low 0.2% (0.1 - 0.5, low estimate - high estimate) of the adult population (aged 15 years and older) (5). In developing countries, like Malawi, there are much higher estimates 11.9% (11.0 - 12.9) of the adult population (aged 15 years and older) (5).
Ever since 1987, HIV treatment, which reduces viral replication and so not a cure, has been available through antiretroviral drugs (3). Furthermore, since 1996, we have seen a substantial reduction in HIV morbidity and mortality due to a combination antiretroviral drug therapy (6). In the last decade there has been newer treatments introduced, like Highly Active Antiretroviral Therapy (HAART), and a concentration on prevention measures (7;8).
However, despite the impact of antiretroviral therapy, HIV is still an important communicable disease and control of transmission a major public health challenge in the UK (9;10). The infection is not only associated with serious morbidity, but also with high treatment costs and care (10). There is still significant mortality associated with HIV, along with a high number of years of life lost. In addition, with HIV, there is a prolonged ‘silent' period, during which it often remains undiagnosed (2).
The following were the key epidemiological findings of the 2008 HPA report:
- "New HIV diagnoses among men who have sex with men continue to increase and over four-fifths of these infections were probably acquired in the UK (10)."
- "The estimated number of persons infected through heterosexual contact within the UK has increased from 540 new diagnoses in 2003 to 960 in 2007, and has doubled, from 11% to 23%, as a proportion of all heterosexual diagnoses during this period (10)."
- "Almost a third (31%) of persons newly diagnosed with HIV were diagnosed late, that is at a point after which therapy should have begun (CD4 cell count less than 200 per mm3) (10)."
- "Seventy percent of the 56,556 persons seen for HIV care were receiving antiretroviral therapy. Almost one in five HIV-infected persons with severe immunosuppression, however, were not on treatment (10)."
- "Uptake of HIV testing in genitourinary medicine and antenatal clinic settings reached 75% and 94%, respectively (10)."
The data presented in Table 1 is from the HIV, Diagnoses Surveillance Tables (8). It shows the new cases of HIV and AIDS diagnoses and Deaths in all HIV-diagnosed individuals, by sex and year (1993-2009).
It is important to note that the data shown in the table for 1993 includes numbers from earlier years and data in 2009 is only up to June of that year, as a result these cannot be compared with the other years and are removed from any figures created.
Taking this into account, even though there has been many campaigns to make people aware of the infection, each year, there is still first time diagnosis with HIV of many thousands of individuals, for example in 2008, there were 4,614 men and 2,684 women (Table 1).
The Health Protection Agency (HPA) reported that by the end of 2007 an estimated 77,400 people were living with the infection (7). It also reported 28% of them were unaware they were infected. So despite HAART and prevention measures, newly diagnosed HIV infection more than doubled in the past decade, from 2,903 in 1997 to 7,495 in 2007 (Table 1).
The data in the table also shows there is a difference in reported new cases of HIV, AIDS and deaths between men and women, with the later having lower numbers. This difference seen will be in part due to the HIV infections in men who have sex with men (MSM).
However, in the estimated 6,840 newly diagnosed with HIV in the UK in 2007, it was estimated that 56% acquired their infection heterosexually and an estimated 38% were men who have sex with men (MSM) (8).
Table 1: HIV and AIDS cases by year of diagnosis and deaths in HIV-infected individuals by year of death and sex. Source: Health Protection Agency Centre for Infections and Health Protection Scotland. Unpublished HIV, Diagnoses Surveillance Tables 01:2009 Table, page 6.
Trends In New Cases Of HIV
Figure 1 show the trends in reported new cases of HIV, AIDS and deaths over time taken from data in Table 1, but care must be taken in intrepreting these trends over time, as each data source is subject to variable reporting delay (8).
The HPA reported in 2007 an estimated, newly diagnosed with HIV, of 6,840 persons (adjusted for reporting delays) and this showed a 12% decline from a peak of 7,800 reported in 2005 (8).
However, when looking at new cases data, diagnosis of HIV in an asymptomatic person is dependent on risk recognition, access and willingness to have an HIV test and test. As a result recent guidelines re-emphasise the use of routine HIV testing in key health services, especially GUM and antenatal services. In addition, these guidelines recommend considering offering HIV testing to all men and women newly registering with a general practice and also with general medical admissions in areas where the prevalence of diagnosed HIV infection is greater than two per 1,000 (15 to 59 year olds) (11).
In England, 42 primary care organisations exceeded this two per 1,000 in 2007, and these can be seen in Map 1 (10).
Trends In New Cases Of AIDS And Deaths
Also from Figure 1, the number of deaths over the past decade has remained stable, but the number of AIDS diagnoses continues to decline. In 2007, there were an estimated 750 first AIDS diagnoses and 540 deaths in HIV infected persons (8). In a meta-analysis of cohort studies, showed that AIDS diagnoses and deaths could be reduced further with earlier diagnosis and treatment initiation (6). This analysis showed delaying combination therapy until a CD4 cell count of 251-350 cells/µl was associated with higher rates of AIDS and death than starting treatment later, 351-450 cells/µl. The authors were 95% confident that the hazard ratio was between 1.04 and 1.57 (HR 1.28) (6). Previous guidelines recommended treatment a CD4 cell count persistently 200 cells/µL (i.e. for 3 months or more) but the British HIV Association guidelines, in response to the above analysis recommend this should be 350 cells/µL (i.e. for 3 months or more) (12).
Infant HIV, AIDS And Death
The figures reported in Table 1 are for adults, 15-59 years old, but the HPA also collates mother to child transmission data as well. The number reported exposed children (born to infected mothers),aged up to 16 years old, was 8,831 and it was found that 9% (816/8831) were infected with HIV (10). However, the 2008 report estimated that exposed infants (born to both diagnosed and undiagnosed women) who are infected has decreased from 17% in 1998 to less than 5% in 2007 (10).
The recommended change in antiretroviral therapy, regarding CD4 count, is important in exposed and infected infants, as a study has shown a positive linear relationship between the mother's CD4+ cell count and that of the infant at one, three, and nine months of age (correlation coefficient at nine months n = 44, 0.48; P<0.002) (13). At the time of delivery, the rate of progression in HIV and possible death by opportunistic infections positively relates to the severity of HIV in the mother.
The national HIV and AIDS new diagnoses and deaths database is the data source used. Access to the data is via the HPA website (http://www.hpa.org.uk). This is an independent agency, although set up by government in 2003 as a special health authority, which uses an integrated approach to protect the public health of the UK (14). It does this by supporting and advising the Department of Health and other interested bodies e.g. NHS, local authorities, etc. Evidence-based research underpins all the HPA's services and information.
Within the HPA, the Centre for Infections (CfI) at Colindale is the base for communicable disease surveillance and specialist microbiology (14). The CfI collects the data for the national HIV and AIDS new diagnoses and deaths database.
The HIV and Sexually Transmitted Infections Department collects the demographic and epidemiological information on adults (aged 15 years and older) newly diagnosed with HIV. This covers England, Wales and Northern Ireland data only. Health Protection Scotland collects the data for new adult HIV cases in Scotland (14).
The Centre for Infections collates the data on a six monthly basis and puts this on the website as unpublished HIV Diagnoses Surveillance Tables. The last report, “HIV in the United Kingdom: 2008 Report (10)”, was published in November 2008. This unpublished and published data provides an understanding of the HIV epidemic in the UK.
The following surveillance centre records are sources for the HIV diagnosis data (8):
- Laboratory and clinician reports
- Reported to the HIV & STI department, Health Protection Agency Centre for Infections (HPA CfI) and to Health Protection Scotland
- Returns to the Oxford Haemophilia Centre for the United Kingdom
- Haemophilia Centre Directors' Organisation
- National Study of HIV in Pregnancy
- At the Royal College of Obstetricians and Gynaecologists
- British Paediatric Surveillance Unit
- Of the Royal College of Paediatrics and Child Health
- Each site collects record of HIV diagnosis, AIDS, and death based on the following definitions:
- "HIV infected individual: an individual for whom HIV diagnosis and/or AIDS, and/or death with HIV infection has been reported (8)."
- "AIDS case: The European AIDS case definition is used for AIDS surveillance in the UK. It is based on that developed in USA as modified in 1987 and 1993, but does not include a CD4 count of less than 200 in an HIV infected person as AIDS defining (8)."
- "Death in an HIV infected individual: these include AIDS and non AIDS related deaths (8)."
- "Date of HIV diagnosis: This is taken to be the date of the first HIV defining event for an individual in the UK, for example, a laboratory report of HIV infection or a diagnosis of AIDS (8)."
They also merge records relating to the same individual into one record. The CfI combines this cumulative data every six-month period, which produce the new HIV diagnosis data set but only for reported individuals.
Therefore, simply taking away deaths from diagnosed HIV individuals does not provide an estimate of prevalence of HIV in the UK. However, to find out HIV prevalence you need to use the Survey of Prevalent HIV Infections Diagnosed (SOPHID) and the report of the Unlinked Anonymous HIV Surveillance Program (Department Of Health Report) (15).
Other sources for the HPA are clinicians reporting all deaths of HIV infected individuals and Office for National Statistics (ONS) reports for all deaths related to AIDS and HIV (16).
Are There Any Problems With HPA Data?
The HPA makes every effort to collect robust data on new cases of HIV from wide range of sources. However, the HPA recognises some limitations in the data they collect:
- “These data inevitably include reports of some individuals who have subsequently left the UK (8).”
- “They may include some whose various records because of, for instance, transcription errors or missing information were not recognised as being related (8)”.
Another factor related to HIV infections is that the current HIV testing does not always seek to distinguish between HIV-1 and HIV-2 infection. However, the HPA reports that 137 diagnosis of HIV-2 infections (without HIV-1 co-infection) and 37 diagnoses of HIV-1 and HIV-2 co-infections by the end of 2008 (8). As there is a geographical link for HIV-2 infections to West Africa (4), and the low number of infections reported by the HPA report this does not demand a major change to current HIV testing.
These factors can have an impact the data presented but the HPA when presenting data always reports potential problems as in the notes for Table 1, which includes some records of the same individuals, unmatchable because of differences in the information supplied.
HIV is still an important communicable disease and control of transmission a major public health challenge in the UK, despite the reduction in new AIDS cases and deaths, the number of new cases of HIV has risen. The role of the HPA in monitoring and reporting trends is crucial in helping to tackle this rise in new cases and its impact on public health.
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(2) WHO. WHO Fact Sheet 1 HIV/AIDS: the infection. Geneva. World Health Organisation; 2009 [accessed 17-11-2009]. Available from: http://www.who.int/hiv/abouthiv/fact_sheet_hiv.htm.
(3) Arya OP, Hart CA. Sexually Transmitted Infections and AIDS in the Tropics. Wallingford: CABI Publishing; 1998.
(4) WHO. WHO Fact Sheet 1 HIV/AIDS: the infection. Geneva. World Health Organisation; 2009 [accessed 17-11-2009]. Available from: http://www.who.int/hiv/abouthiv/fact_sheet_hiv.htm.
(5) UNAIDS. 2008 Report on the global AIDS epidemic. Geneva: UNAIDS; 2008.
(6) Sterne JA, May M, Costagliola D, de WF, Phillips AN, Harris R, et al. Timing of initiation of antiretroviral therapy in AIDS-free HIV-1-infected patients: a collaborative analysis of 18 HIV cohort studies. Lancet 2009 Apr 18;373(9672):1352-63.
(7) HPA Centre for Infections. Testing Times: HIV and other Sexually Transmitted Infections in the United Kingdom: 2007. London: Health Protection Agency; 2007.
(8) HPA Centre for Infections. United Kingdom HIV New Diagnoses to End of June 2009. London: Health Protection Agency; 2009.
(9) Lattimore S, Yin Z, Logan L, Rice B, Thornton A, Molinar D, et al. Situation of HIV infections and STIs in the United Kingdom in 2007. Euro Surveill 2008 Dec 4;13(49).
(10) HPA Centre for Infections. HIV in the United Kingdom: 2008 report. London: Health Protection Agency; 2008.
(11) British HIV Association, British Association of Sexual Health and HIV, British Infection Society. UK National Guidelines for HIV Testing 2008. London: British HIV Association; 2008.
(12) Gazzard BG. British HIV Association Guidelines for the treatment of HIV-1-infected adults with antiretroviral therapy 2008. HIV Med 2008 Oct;9(8):563-608.
(13) Blanche S, Mayaux MJ, Rouzioux C, Teglas JP, Firtion G, Monpoux F, et al. Relation of the Course of Hiv-Infection in Children to the Severity of the Disease in Their Mothers at Delivery. New England Journal of Medicine 1994;330(5):308-12.
(14) HPA. Who we are. London. Health Protection Agency; 2009 [accessed 19-12-2009]. Available from: http://www.hpa.nhs.uk/HPA/AboutTheHPA/WhoWeAre/.
(15) HPA. Numbers accessing HIV care. London. Health Protection Agency; 2009 [accessed 19-11-2009]. Available from: http://www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1201094588844/.
(16) Office for National Statistics. Focus on health. Basingstoke: PALGRAVE MACMILLAN; 2006.