The human immunodeficiency virus (HIV) which causes acquired immune deficiency syndrome (AIDS) has brought about a global epidemic of massive proportions. HIV is a retrovirus and also the term often applied to the infection before the deterioration of the immune system to produce a full-blown picture of AIDS.
Within the UK the HPA Centre for Infections receives information on HIV infections from several sources. The major sources of information are reports from clinicians and laboratories of newly diagnosed infections, an annual survey of all patients seen for HIV-related treatment or care, and a family of unlinked anonymous surveys which test blood samples taken for other investigations, after they have been irreversibly unlinked from any patient identifiers. All reporting methods are confidential and avoid the use of names.
Epidemiology
Worldwide
It has become a massive problem and according to the World Health Organization in 2008:[1]
- An estimated 33.4 million people are living with HIV worldwide. 2006 figures were 38.6 million.
- There were 2.7 million newly infected people in 2008. 2006 figures were 4.1 million.
- 2.0 million people died of AIDS in 2008. 2006 figures were 2.8 million.
Poor record keeping and returns from some countries make these figures unreliable.
In Africa antiretroviral treatment coverage has also increased:[1]
In Africa antiretroviral treatment coverage has also increased:[1]
- In 2003 in Sub-Saharan Africa, approximately 100,000 people were receiving treatment; 2% of those needing it.
- In 2008 2,120,000 people were receiving treatment; 30% of those needing it.
- The percentage of pregnant women receiving antiretrovirals for preventing mother-to-child transmission of HIV in Sub-Saharan Africa increased from 15% in 2005 to 45% in 2008.
- The median percentage of people 15-49 years old who know their HIV status, through an HIV test in Sub-Saharan Africa, was 22%. High and low respectively Sierra Leone 100%, Ghana 7%.
- The percentage of children under 18 years old who have lost one or both parents, in countries with HIV prevalence greater than 1 percent, is 28% in Lesotho, 24% in Zimbabwe and 21% in Swaziland (3 highest).
While this progress is notable, the HIV prevention response falls short in many areas. The response to the problem of AIDS varies considerably between countries, irrespective of risk. Some are just slow to take the matter seriously whilst others are still denying that it is a problem in their country. In many parts of Africa the prevalence appears to be getting stable. This means that the number of people dying from the disease is roughly equal to the number of new cases.
According to a report from the Health Protection Agency (HPA), there were an estimated 83,000 adults aged over 15 with HIV in the UK in 2008, 27% of whom were unaware of their infection.[2] The number of deaths among HIV-infected people has remained stable over the past decade, and a total of 525 people (387 men and 138 women) infected with HIV were reported to have died in 2008. There were 7,298 new diagnoses in 2008 in the UK. This represents a slight decline on previous years, predominantly due to fewer diagnoses among young people who acquired their infection abroad.United Kingdom
Within the UK the HPA Centre for Infections receives information on HIV infections from several sources. The major sources of information are reports from clinicians and laboratories of newly diagnosed infections, an annual survey of all patients seen for HIV-related treatment or care, and a family of unlinked anonymous surveys which test blood samples taken for other investigations, after they have been irreversibly unlinked from any patient identifiers. All reporting methods are confidential and avoid the use of names.
Description
AIDS is currently defined as an illness characterised by the development of one or more AIDS-indicating conditions. It is diagnosed in people infected with HIV when they develop certain opportunistic infections or malignancies for the first time. The following list relates to diagnosis in adults. Congenital HIV and childhood AIDS has its own separate article.
| AIDS-defining conditions in adults | |
|---|---|
| Candidiasis of bronchi, trachea or lungs. | Lymphoma, Burkitt's (or equivalent term). |
| Candidiasis, oesophageal. | Lymphoma, immunoblastic (or equivalent term). |
| Cervical carcinoma, invasive. | Lymphoma, primary, of brain. |
| Coccidioidomycosis, disseminated or extrapulmonary. | Mycobacterium avium complex (MAC) or M. kansasii, disseminated or extrapulmonary. |
| Cryptococcosis, extrapulmonary. | Mycobacterium tuberculosis, any site (pulmonary or extrapulmonary). |
| Cryptosporidiosis, chronic intestinal (>1 month's duration). | Mycobacterium, other species or unidentified species, disseminated or extrapulmonary. |
| Cytomegalovirus (CMV) disease (other than liver, spleen or nodes). | Pneumocystis jirovecii pneumonia. |
| CMV retinitis (with loss of vision). | Pneumonia, recurrent. |
| Encephalopathy, HIV-related. | Progressive multifocal leukoencephalopathy. |
| Herpes simplex: chronic ulcer(s) (>1 month's duration); or bronchitis, pneumonitis or oesophagitis. | Salmonella septicaemia, recurrent. |
| Histoplasmosis, disseminated or extrapulmonary. | Toxoplasmosis of brain. |
| Isosporiasis, chronic intestinal (>1 month's duration). | Wasting syndrome due to HIV. |
| Kaposi's sarcoma. | |
This case definition includes 3 new clinical conditions of pulmonary tuberculosis, recurrent pneumonia and invasive cervical carcinoma.
Presentation
When HIV infection is diagnosed in a routine test, as for blood donation, in pregnancy, or after counselling a person with a lifestyle that puts him or her at risk, there is not usually full AIDS but just infection with HIV. When the disease is suspected, HIV counselling must precede testing. There is a characteristic presentation of the infection that is described in the separate article Primary HIV infection. Once the diagnosis is made, the separate article Managing HIV Positive Individuals in Primary Care becomes relevant. The separate article HIV and Skin Disorders outlines the many dermatological manifestations of the disease.
Modes of transmission
Awareness of modes of transmission is very important, as the key to tackling this disease lies less in treating it than in preventing its spread. The relative importance of the various means of transmission varies considerably from country to country and even within countries. The following is derived from information on the HPA website and is applicable to the UK.[3]
Sex between men
38% of infections in the UK have occurred through sex between men and this group remains at greatest risk. There has been no evidence in recent years of a decline in the numbers of new infections in this group and over 1,800 new diagnoses of HIV are currently occurring each year.
Despite generally high levels of awareness of the risks for HIV acquisition, in 2008 an estimated 32% of adults aged over 15 years were diagnosed with a CD4 cell count ≤200 per mm3 within three months of diagnosis.[2] The percentage diagnosed with CD4 cell counts ≤350 per mm3 (the threshold at which treatment should be considered according to 2008 British HIV Association guidelines) was 43%.
Estimation of current incidence of HIV is difficult. A newly developed laboratory technique, which identifies recently acquired infections, suggests there has been little change in HIV incidence in men who have sex with men over recent years. If there has been a decrease in transmissibility associated with antiretroviral treatment in those diagnosed it may have been offset by an increase in risky behaviours. London has been the main focus of the HIV epidemic in the UK. Of those infected by sex between men, 55% live in London.
This must be a great disappointment to those who have worked hard to educate this group.
Despite generally high levels of awareness of the risks for HIV acquisition, in 2008 an estimated 32% of adults aged over 15 years were diagnosed with a CD4 cell count ≤200 per mm3 within three months of diagnosis.[2] The percentage diagnosed with CD4 cell counts ≤350 per mm3 (the threshold at which treatment should be considered according to 2008 British HIV Association guidelines) was 43%.
Estimation of current incidence of HIV is difficult. A newly developed laboratory technique, which identifies recently acquired infections, suggests there has been little change in HIV incidence in men who have sex with men over recent years. If there has been a decrease in transmissibility associated with antiretroviral treatment in those diagnosed it may have been offset by an increase in risky behaviours. London has been the main focus of the HIV epidemic in the UK. Of those infected by sex between men, 55% live in London.
This must be a great disappointment to those who have worked hard to educate this group.
Sex between men and women
Nowadays, the number of new cases of AIDS acquired from heterosexual intercourse is greater than from homosexual activity. However, most of these cases were not acquired in this country. Almost 82% are recorded as having been acquired abroad with around 70% of the total from Africa. In the late 1980s and early 1990s the majority of the African infections were acquired in East Africa but, more recently, the impact of the HIV epidemics in South Eastern Africa has been greater. Infections acquired in Asia and in Latin America/the Caribbean have shown a slight upward trend since the late 1990s but this is modest compared with the contribution of the African epidemic.
In several other European countries there has been much more heterosexual spread from individuals infected through intravenous drug abuse than in the UK. The numbers of acquisitions from high-risk partners diagnosed each year have remained fairly steady and constitute a decreasing percentage of the total of new diagnoses, at around 1.5% of the total of new diagnoses amongst heterosexuals.
With the rise in the numbers of those who acquired their infections heterosexually there has been an increase in the number of women diagnosed. The male:female ratio for all new infections diagnosed in 1985/1986 was approximately 14:1, whereas in 2008 it was about 1.6:1.
It is estimated that around 33% of all HIV infections acquired heterosexually are currently undiagnosed. Many heterosexuals remain undiagnosed until testing is prompted by HIV-related symptoms late in the course of illness. Around two thirds of those with heterosexually acquired infection are being diagnosed late with a CD4 count of less than 350 cells/mm3.
Markers of promiscuity, such as the numbers of new cases of gonorrhoea, are increasing among heterosexuals and this must mean an increased risk of HIV transmission too.
In several other European countries there has been much more heterosexual spread from individuals infected through intravenous drug abuse than in the UK. The numbers of acquisitions from high-risk partners diagnosed each year have remained fairly steady and constitute a decreasing percentage of the total of new diagnoses, at around 1.5% of the total of new diagnoses amongst heterosexuals.
With the rise in the numbers of those who acquired their infections heterosexually there has been an increase in the number of women diagnosed. The male:female ratio for all new infections diagnosed in 1985/1986 was approximately 14:1, whereas in 2008 it was about 1.6:1.
It is estimated that around 33% of all HIV infections acquired heterosexually are currently undiagnosed. Many heterosexuals remain undiagnosed until testing is prompted by HIV-related symptoms late in the course of illness. Around two thirds of those with heterosexually acquired infection are being diagnosed late with a CD4 count of less than 350 cells/mm3.
Markers of promiscuity, such as the numbers of new cases of gonorrhoea, are increasing among heterosexuals and this must mean an increased risk of HIV transmission too.
Injecting drug users
The total number of cases of HIV in the UK includes 170 cases from injecting drug use (IDU). IDU has played a smaller part in the HIV epidemic in the UK than it has in many other European countries and the numbers of new diagnoses have been around 100 for the last few years. The age of diagnosis rose throughout the 1990s, suggesting that new diagnoses are being made on an ageing population largely infected in the mid-1980s and that new infections are becoming less frequent. These figures mask geographical variations and, in Eastern Scotland, there was rapid HIV spread through IDU in the early to mid-1980s.
HIV infected injecting drug users are predominantly male as are all drug users. This has meant that the relatively small heterosexual spread from infected drug users has been predominantly to women, with 74% of those reported infected by this route being female.
Behavioural changes among injectors and the prompt introduction of harm reduction measures such as needle exchange programmes from the mid- 1980s probably prevented many other urban areas in the UK from experiencing the localised epidemics on the scale seen in Scotland. In the UK, sharing rates remain higher than in the mid-1990s with almost one in three injectors in the Unlinked Anonymous survey of injecting drug users reporting direct sharing of needles and syringes in the previous 4 weeks. The continuing transmission of hepatitis B and hepatitis C in those aged under 25 shows the potential for further HIV spread among injecting drug users.
HIV infected injecting drug users are predominantly male as are all drug users. This has meant that the relatively small heterosexual spread from infected drug users has been predominantly to women, with 74% of those reported infected by this route being female.
Behavioural changes among injectors and the prompt introduction of harm reduction measures such as needle exchange programmes from the mid- 1980s probably prevented many other urban areas in the UK from experiencing the localised epidemics on the scale seen in Scotland. In the UK, sharing rates remain higher than in the mid-1990s with almost one in three injectors in the Unlinked Anonymous survey of injecting drug users reporting direct sharing of needles and syringes in the previous 4 weeks. The continuing transmission of hepatitis B and hepatitis C in those aged under 25 shows the potential for further HIV spread among injecting drug users.
Mother to child
There are separate articles on Congenital HIV and its Prevention and Management of HIV in Pregnancy and so this section will be shortened.
HIV prevalence among women giving birth remained highest in London (3.7 per 1,000) and has been stable since 2004. In the rest of England the prevalence has increased five-fold over the past decade but remains relatively low (1.5 per 1,000) in 2008.
By the end of June 2009, 9,874 children (including individuals now aged 16 years or older, but diagnosed before their 16th birthday) had been diagnosed in the UK. Almost all children diagnosed with HIV in the UK in 2008 were reported to have been infected through mother-to-child transmission, and 60% of them were born abroad. Most of the children infected through other routes were infected through blood or blood product treatment in the early 1980s. Since viral inactivation of blood products was introduced in 1985, no transmissions through blood products have been reported in the UK.
About 92% of women with HIV are diagnosed before delivery.They can benefit from interventions which can reduce the risk of mother-to-child transmission to well under 3%. These interventions include: antiretroviral therapy, Caesarean section delivery and avoidance of breast-feeding.
HIV prevalence among women giving birth remained highest in London (3.7 per 1,000) and has been stable since 2004. In the rest of England the prevalence has increased five-fold over the past decade but remains relatively low (1.5 per 1,000) in 2008.
By the end of June 2009, 9,874 children (including individuals now aged 16 years or older, but diagnosed before their 16th birthday) had been diagnosed in the UK. Almost all children diagnosed with HIV in the UK in 2008 were reported to have been infected through mother-to-child transmission, and 60% of them were born abroad. Most of the children infected through other routes were infected through blood or blood product treatment in the early 1980s. Since viral inactivation of blood products was introduced in 1985, no transmissions through blood products have been reported in the UK.
About 92% of women with HIV are diagnosed before delivery.They can benefit from interventions which can reduce the risk of mother-to-child transmission to well under 3%. These interventions include: antiretroviral therapy, Caesarean section delivery and avoidance of breast-feeding.
Blood products and blood transfusion
Production of the clotting factor concentrates, mainly to treat patients with haemophilia A and haemophilia B (Christmas disease), involves the pooling of very many donations and a single donation could contaminate a batch of concentrate used to treat many patients. There have been no recorded transmissions of HIV by this route in the UK since the introduction of heat inactivation of concentrates and donor screening in 1985.
Around 1,350 people in the UK have been infected through treatment with blood factor concentrates and all but 13 are male. Two-thirds have died, 31% of them without AIDS having been reported. People with haemophilia may die from liver disease and haemorrhage before the development of an AIDS-defining condition.
Since 1985, all blood donations have been screened for HIV antibody. There have been only two proven incidents of antibody-negative blood infectious for HIV being accepted for transfusion in the UK since then (the donor being in the 'window period' when blood is infectious because of recent HIV infection but too early for antibodies to be reliably detected by the screening antibody test). Most diagnoses from blood transfusions come from areas of the world where screening is unreliable and inconsistent.
Around 1,350 people in the UK have been infected through treatment with blood factor concentrates and all but 13 are male. Two-thirds have died, 31% of them without AIDS having been reported. People with haemophilia may die from liver disease and haemorrhage before the development of an AIDS-defining condition.
Since 1985, all blood donations have been screened for HIV antibody. There have been only two proven incidents of antibody-negative blood infectious for HIV being accepted for transfusion in the UK since then (the donor being in the 'window period' when blood is infectious because of recent HIV infection but too early for antibodies to be reliably detected by the screening antibody test). Most diagnoses from blood transfusions come from areas of the world where screening is unreliable and inconsistent.
Investigations
Investigations for HIV are described in the separate Human Immunodeficiency Virus (HIV) article. Further investigations for AIDS-defining conditions may be indicated. Media interventions can improve the uptake of testing but this might not be sustained.[4]
Management
The basis of management is described in the separate article on HIV. There may be defining conditions such as Pneumocystis jirovecii pneumonia that will need treatment. Highly active antiretroviral therapy (HAART) has improved the prognosis enormously in terms of duration of survival but premature death is to be expected.
HAART represents the use of at least 3 antiretroviral drugs. New therapies and new regimens are being produced and these should all be assessed by randomised controlled trials. Therefore, as far as possible, everyone with the condition should be included as part of a trial. They will not be expected to take an inert placebo, as effective treatments have been demonstrated and so it is a matter of comparing a new regimen with an existing one, not proving that a new drug is better than nothing. Trials should use standard means of assessment so that meta-analysis may be performed.[5]
Treatments with HAART have shown considerable progress in the past decade with impressive improvements in life expectancy and quality of life.[6] There are still many problems. Although HAART is able to suppress the viral load in the plasma, it fails to eradicate it, and once HAART is initiated, treatment needs to be continued for life. The side-effects of long-term HAART include lipodystrophy, lactic acidosis, insulin resistance, and hyperlipidemia. In addition, patients require high adherence to the therapy to achieve viral suppression and prevent the development of a drug-resistant virus. Modern regimes are less onerous than older ones. They are simpler and involve fewer tablets, whereas it used to be necessary to take 16 to 20 tablets a day.
Some people will wish to use herbal remedies and a Cochrane review was able to find a small number of trials, some of which seemed to have adequate methodology.[7]There was no significant clinical benefit and objective criteria such as CD4 count were unaffected.
There may be some benefits from prophylactic treatment. A Cochrane review found some benefit in treating latent tuberculosis.[8] Another review found only one trial that examined the benefit of prophylactic co-trimoxazole in children. It was from Zambia and the result was positive.[9] The value of prophylaxis against oropharyngeal candidiasis is uncertain, especially in children. There may be some benefit but at a risk of resistance developing and for poorer countries the cheaper options should be examined.[10]
HAART represents the use of at least 3 antiretroviral drugs. New therapies and new regimens are being produced and these should all be assessed by randomised controlled trials. Therefore, as far as possible, everyone with the condition should be included as part of a trial. They will not be expected to take an inert placebo, as effective treatments have been demonstrated and so it is a matter of comparing a new regimen with an existing one, not proving that a new drug is better than nothing. Trials should use standard means of assessment so that meta-analysis may be performed.[5]
Treatments with HAART have shown considerable progress in the past decade with impressive improvements in life expectancy and quality of life.[6] There are still many problems. Although HAART is able to suppress the viral load in the plasma, it fails to eradicate it, and once HAART is initiated, treatment needs to be continued for life. The side-effects of long-term HAART include lipodystrophy, lactic acidosis, insulin resistance, and hyperlipidemia. In addition, patients require high adherence to the therapy to achieve viral suppression and prevent the development of a drug-resistant virus. Modern regimes are less onerous than older ones. They are simpler and involve fewer tablets, whereas it used to be necessary to take 16 to 20 tablets a day.
Some people will wish to use herbal remedies and a Cochrane review was able to find a small number of trials, some of which seemed to have adequate methodology.[7]There was no significant clinical benefit and objective criteria such as CD4 count were unaffected.
There may be some benefits from prophylactic treatment. A Cochrane review found some benefit in treating latent tuberculosis.[8] Another review found only one trial that examined the benefit of prophylactic co-trimoxazole in children. It was from Zambia and the result was positive.[9] The value of prophylaxis against oropharyngeal candidiasis is uncertain, especially in children. There may be some benefit but at a risk of resistance developing and for poorer countries the cheaper options should be examined.[10]
Impact of acquired immune deficiency syndrome in Africa
The impact of AIDS in southern Africa has been devastating. The average expectation of life, which had been improving, has started to decline. Some communities have been very hard hit with many deaths and economic hardship related to loss of the workforce of young adults. Children who have not yet reached 10 years old find that one, then both parents become ill, need to be cared for and then die, leaving them to care for themselves and for younger brothers and sisters. This takes them out of school and so they also miss out on education about AIDS. Social care in the community may be hampered by lack of resources due to so many such cases or they may be shunned because of the social stigma. Vertical transmission means that the troubled child may also become ill and die. They are robbed of their childhood. They are robbed of their lives.
The cost of drugs can be prohibitive in such poor economies. If they are not provided by the state, they can be ill afforded by those who need them. The cost of therapy has come down and the price of drugs is being subsidised but the problem of treating so many poor people remains.
The WHO report was quite encouraging with regard to Africa and epidemiology figures above support a slowly improving picture.
The cost of drugs can be prohibitive in such poor economies. If they are not provided by the state, they can be ill afforded by those who need them. The cost of therapy has come down and the price of drugs is being subsidised but the problem of treating so many poor people remains.
The WHO report was quite encouraging with regard to Africa and epidemiology figures above support a slowly improving picture.
Prevention
The eradication of AIDS is based on prevention rather than cure: this means education and action. Education promotes the use of barrier contraception and advises against risk-taking behaviour eg promiscuity or intravenous drug use. However education can be problematic when a respected body like the Roman Catholic church appears to dispute the risks.[11][12]
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