Against AIDS, not against people with AIDS.
Acquired immune deficiency syndrome (AIDS) is a group of symptoms caused by the human immunodeficiency virus (HIV), which destroys the immune system. This weakens the body's defences and makes it easy prey for all kinds of infections (called opportunistic infections) and cancers. The virus passes on when mucous membranes or blood come into contact with infected fluids such as blood, semen, vaginal fluids or breast milk.
It is passed on through sex, blood transfusion, and from mother to baby in pregnancy, at birth or through breastfeeding.
AIDS killed 2.1 million people in 2007, and 33.2 million people were living with HIV, including 600,000 in the Arab countries (World Health Organization estimates).
There is no cure and no vaccine, but antiviral drugs have greatly improved survival. These drugs are very expensive and not available in every country, so prevention is the best way to fight the disease.
Symptoms
The symptoms of AIDS come from the weakened immune system and don't usually appear in healthy people. Most are infections caused by bacteria, viruses, fungi and parasites. People with AIDS are also prone to several cancers, including Kaposi's sarcoma and lymphomas, and to symptoms such as fever, sweating (especially at night), swollen glands, chills, weakness and weight loss. The opportunistic infections vary from one region to another.
Chest infections
One of the main causes of death in AIDS is chest infection, especially Pneumocystis pneumonia. Tuberculosis is also common in people with AIDS, although rare in general. It can occur early in the disease and can be treated with antibiotics, but it is a big problem in developing countries, where it is widespread among people with AIDS and can affect the bone marrow, bones, urinary and digestive tracts, liver, lymph nodes and nervous system.
Digestive infections
Inflammation of the oesophagus (the tube between the throat and the stomach) can be caused by fungal or viral infection. Unexplained diarrhoea can come from gut infections such as Salmonella, Shigella and Listeria, or be a side effect of HIV drugs.
Brain and nerve problems
Brain inflammation caused by toxoplasma can occur and spread to the eyes and lungs. Meningitis caused by cryptococcus can cause fever, headache, nausea, vomiting and seizures, and can kill if untreated.
The myelin (the insulating sheath around nerve fibres) can break down. Some patients develop AIDS dementia, caused when the virus attacks immune cells, which respond by releasing toxins that kill brain cells. Problems with speech, behaviour and movement occur in 10–20% of patients in Western countries and 1% in India, perhaps because of different subtypes of the virus.
Cancers
The best known is Kaposi's sarcoma, one of the first signs by which AIDS was recognised in the 1980s, in gay men. It usually appears as purple patches on the skin but can spread to other organs, especially the mouth. It is caused by a herpes virus (HHV-8).
Lymphomas caused by the Epstein-Barr virus (EBV) are also common, as is cervical cancer caused by the human papillomavirus (HPV).
The cause
The disease is caused by HIV, which attacks the body's immune cells, multiplies inside them and stops them protecting the body. The virus is found in the blood, but also in other body fluids (saliva, mucus, genital fluids). Its main target is CD4+ cells, which it destroys until very few are left in the blood (fewer than 200 per microlitre). This is what wrecks immunity.
Sexual transmission
The virus passes on when someone's genitals come into contact with the genital, oral or anal fluids of an infected person. Without protection, the receiving partner is at greater risk: a woman, for example, is at greater risk than a man because she receives semen. Anal sex is riskier than vaginal or oral sex, but oral sex is not completely safe, as both partners are at risk. Sexual assault raises the risk because of bruising and small tears.
Other sexually transmitted infections, such as syphilis, more than quadruple the risk, because of sores on the genitals (visible or microscopic) and infected cells in semen or vaginal fluids.
The chance of infection depends on the stage of the disease and on the immune health of the exposed person. No virus in the blood serum doesn't mean no virus in semen or genital fluids. In women, the risk varies with the hormonal changes of the menstrual cycle and the amount of fluid.
A person infected with one strain of HIV can be infected with another strain later. Infection is linked with long-term multiple sexual partners.
Through the blood
The virus passes on through shared drug needles, to people with haemophilia and to people receiving blood transfusions. Sharing needles caused a third of infections in North America, China and Eastern Europe. The risk from a single prick with a contaminated needle is 1 in 150, and it can be reduced with post-exposure drugs. Tattoos and piercings also carry a risk.
Although the risk from blood transfusion is very small in developed countries, the World Health Organization estimates that 5–10% of new infections worldwide come from transfusions.
From mother to baby
The virus passes from mother to baby in the last weeks of pregnancy or during birth. Without treatment, 25% of babies are infected; with treatment and a caesarean section, this drops to 1%. Breastfeeding carries a 4% risk.
Stages
The World Health Organization divides the disease into four stages:
- Stage I: no symptoms; not classed as AIDS.
- Stage II: mild symptoms in the mucous membranes and chest infections.
- Stage III: long-lasting unexplained diarrhoea, bacterial infections and lung tuberculosis.
- Stage IV: toxoplasma brain infection, inflammation of the oesophagus, Kaposi's sarcoma.
There is also an American classification based on the CD4+ count.
Lab tests
There are two main tests. The first looks for IgG and IgM antibodies against the virus: their presence means the person has been exposed and the body is fighting the virus. A positive result must be repeated to confirm it, because this test can give false results. The second looks for the virus's genetic material (RNA) in the blood by PCR. It is expensive but much more accurate, and its results should also be confirmed with the antibody test.
Prevention
No case has been recorded of the virus spreading through tears, saliva or urine, so this risk is negligible.
Look after children's hygiene, wash off any fluids from other people, especially mucus and blood, and keep sharp objects such as needles and scissors out of their reach.
Most infections come from unprotected sex. Condoms (male or female) greatly lower the risk, as well as preventing pregnancy: over the long term they cut infection between partners by about 80%, and by more when used correctly every time. The male condom is the best single means of protection, but it must not be used with oil-based lubricants: manufacturers state that petroleum jelly, fats, butter, oils and paraffin dissolve condoms and make holes in them. Use water-based lubricants instead.
Female condoms are made of polyurethane, which can be used with oil-based lubricants. A female condom has a flexible ring that sits inside the vagina; it is larger than a male condom and is squeezed to put it in place. Female condoms are less available and more expensive.
When condoms are used, the chance of infecting a partner is less than 1% a year. Studies have also shown that male circumcision cuts the risk of infection by 60%, although experts fear this could encourage riskier sex.
Treatment
There is still no vaccine, but there is a four-week post-exposure treatment, which can cause diarrhoea, tiredness, nausea and anxiety.
The main treatment is highly active antiretroviral therapy (HAART): a combination of at least three drugs from at least two families. These are mainly nucleoside reverse transcriptase inhibitors (NRTIs), protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs), which block different steps of the virus's life cycle. Children are treated more aggressively than adults, because the disease progresses faster in them.
Treatment controls the symptoms and the amount of virus in the blood, but it doesn't cure the patient, and the virus comes back as soon as treatment stops, so it is lifelong. It improves quality of life and general health. Untreated, the disease usually takes 9–10 years to progress, and after symptoms appear (stage IV) patients live 9.2 months on average; treatment can extend this to 4–12 years.
Treatment has significant side effects, can lose its effect or meet drug resistance, and patients may struggle to keep taking the many pills involved. Long-term side effects can include loss or redistribution of body fat, diarrhoea, insulin resistance (diabetes), a higher risk of heart disease, and birth defects. The drugs are also very expensive, and most people can't afford them.
Alternative treatments
Many herbal remedies with antiviral effects are used, but their effect is limited or unproven. Some studies suggest vitamin combinations to slow the disease; vitamin A may help children, and selenium has improved CD4+ counts, but only alongside other drugs, not on its own. These treatments may improve patients' lives, but it is not certain that they lengthen them.
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