Everything you need to know about HIV and AIDS

What is HIV?

HIV (human immunodeficiency virus) is a virus that affects cells in the immune system, gradually destroying them so that the person becomes susceptible to infections and cancers. People who have been infected with HIV usually remain in good health for several years—and may stay well for as long as 15 years.

But, in time, the decline in the immune system accelerates and the person usually succumbs to various diseases, leading to a diagnosis of AIDS (Acquired Immune Deficiency Syndrome).

The three most common methods by which the virus is passed are:

  • during sexual intercourse, both heterosexual and homosexual
  • from mother to baby before or during birth or during breastfeeding
  • when injecting drug abusers share needles and other equipment.

It is also possible for HIV to be transmitted through organ transplants, blood transfusion and the use of blood products; this is rare in the UK because donated blood and tissue are screened for the virus.

Saliva, sweat and urine do not usually contain enough HIV to infect another person.


What are the initial symptoms of HIV?

During the first three to five days after infection, the virus replicates in the lymph glands before spreading viral particles through the blood. The first stage of infection may go unnoticed, but 70 per cent of those affected experience brief flu-like symptoms such as fevers, night sweats, swollen glands, diarrhoea and rash. 

A blood test done at this time will show a high number of HIV viral particles—this is known as a high 'viral load'.
About three to six months after infection, the body begins to produce antibodies to the virus. An HIV antibody test checks for these antibodies in patients' blood. People whose blood contains the antibodies are said to be HIV-positive.


Symptoms of HIV

Apart from the initial symptoms at the time of infection, mild symptoms such as fatigue, weight loss, night sweats and oral thrush occur on average five to seven years after HIV infection.

Within an average of ten years the immune system has suffered severe damage. Patients become vulnerable to a range of 'opportunistic infections'. These are caused by bacteria, fungi, protozoa and other infectious agents that an intact immune system can usually deal with, but which take advantage of the opportunity provided by weakened immunity to attack the body.

Problems commonly associated with HIV usually strike either the lungs or the central nervous system or the gastro-intestinal tract. They include Kaposi's sarcoma and types of lymphoma, as well as more than 20 infections such as oral candida (thrush), tuberculosis and Pneumocystis cariniipneumonia.


Transmission of HIV

HIV is transmitted in many bodily fluids, including blood, vaginal fluid, semen and breast milk from an infected person. Although HIV has not been reported to be transmitted by tears or saliva, it has been reported after oral sex, especially where there are open sores in the mouth or gum disease. Using a condom for sex is the most effective way of protecting yourself against HIV infection. Be cautious about new sexual partners—an apparently healthy person may be HIV-positive and infectious. Sexual partners from sub-Saharan Africa are the highest risk.

Injecting drug users should never share needles or other equipment. People in the developed world are highly unlikely to be infected with HIV by blood transfusion. Since 1985 donated blood and blood products have been screened for HIV.

HIV is not passed on through everyday social contact with an infected person. Touching, shaking hands, hugging, coughing or sneezing cannot transmit the virus.


Who is at risk?

Anyone exposed to HIV infection through sex without a condom or contaminated blood can be infected with HIV. High-risk groups include homosexuals or bisexuals who engage in unprotected sex. This category represents 40 per cent of new cases in the UK.

Injecting drug users constitute 3 per cent of new cases in the UK.

Other high-risk groups are children born to infected mothers and adults in countries of high heterosexual HIV transmission—for example, countries in sub-Saharan Africa. Heterosexually acquired HIV is rare in the UK but accounts for nearly 90 per cent of cases worldwide.

HIV tests and pregnant women

There is a chance that a pregnant woman who is HIV-positive will pass on the infection to her child. All babies born to HIV-positive mothers have antibodies to the virus in their blood, but most do not have the virus itself and will lose the antibodies by the age of 18 months. From about three months old, babies can take the PCR test, which looks for the virus rather than the antibodies identified in the HIV antibody test. Only one in six babies born to HIV-positive mothers has the virus.

An HIV-positive woman can protect her baby by taking drugs that reduce the chances of passing on the virus. She will be advised to have her baby by Caesarean section, which also reduces the chances of passing on the virus, and to bottle-feed rather than breast feed her baby because the virus can be passed on in breast milk.

In some antenatal clinics all pregnant women are offered the HIV test. In others, women have to ask to take it.

Being HIV-positive does not affect your fertility. But if you decide to start a family and your partner is not HIV-positive, he risks contracting the infection during sex without a condom.


Living with HIV

If you are HIV-positive, you can expect to live a normal life and feel healthy for many years and you will need only occasional monitoring of your HIV status. There is a real risk of passing on HIV, but it can only happen through unprotected sex or sharing injecting equipment.

It is vital to understand HIV, the risks, and how to protect yourself and others. You need to decide whether and how to tell others about your condition.

As HIV progresses to AIDS you will need to plan your lifestyle and drug regime carefully to limit the effects of the likely infections, muscle wasting and loss of strength. Local and national charities and support groups can provide assistance at all stages to people suffering from HIV and AIDS.

Treating HIV

The outlook for HIV sufferers has improved in recent years with the introduction of Highly Active Anti-Retroviral Therapy (HAART). With HAART, patients take a combination of two or three anti-HIV drugs – research has shown this to be more effective than taking any single anti-HIV drug.

Currently available drugs slow the replication of the virus and subsequent immune damage. But there is still no cure or vaccine for HIV/AIDS.

AZT, now called ZDV (for zidovudine), is the most widely used drug for HIV. Some people find ZDV ineffective or cannot tolerate its side effects, which include leg cramps, diarrhoea or anaemia. Alternatives include didanosine (ddI)or dideoxycytidine (ddC), but these, too, have potential risks.

The HIV virus can become resistant to particular anti-HIV drugs and sufferers may have to change the drugs or combinations of drugs they are using. The viral load test is used to check how well particular drugs are working. The test provides evidence of the number of viral particles in a patient's blood—the fewer particles, the more effective the drug.

In deciding whether to treat the initial stages of HIV infection, patients and doctors must weigh the benefit from HAART against the side effects and the risk of developing a drug-resistant virus early in the disease. Studies suggest that slowing the early rapid replication of the virus may delay the progression to AIDS. But HIV has not yet been eradicated by treating it in the early stage.

Treatment with trimethoprim-sulfamethoxazole (TMP-SMX) may protect people with AIDS against Pneumocystis cariniipneumonia (PCP), the most common respiratory tract infection to strike AIDS patients.



AIDS patients are vulnerable to infections, and it is these infections, rather than the virus itself, that can lead to death. A patient may recover from an infection only to succumb eventually to another one. Despite improving survival rates due to HAART, people with HIV still have a shortened lifespan.


Terrence Higgins Trust: 52–54 Grays Inn Road, London WC1X 8JU; helpline 0845 122 1200 The trust is the UK's largest HIV and AIDS charity.
National AIDS Trust: New City Cloisters, 188–196 Old Street, London EC1V 9FR; helpline 0800 567 123
Joint United Nations Programme on HIV/AIDS