Understanding HIV

Learning the facts raises your awareness of HIV and allows you to take better care of your own health

  • Published: 20/09/2024

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HIV and AIDS

HIV (Human Immunodeficiency Virus) is a virus which affects the immune system – the body’s defence against diseases. HIV stays in the body for life, but treatment can keep the virus under control and the immune system healthy.

Without medication people with HIV can develop AIDS (Acquired Immune Deficiency Syndrome), although this is now rare in the UK. In healthcare, AIDS is now commonly referred to as Advanced HIV, and it occurs when the immune system is unable to effectively protect against infections.

Advanced HIV involves the presence of HIV and one of a specific list of what are sometimes known as ‘AIDS defining’ illnesses, such as tuberculosis, pneumonia and some types of cancer.

If HIV is caught early and you begin treatment,  your immune system will stay strong and continue to provide protection. If HIV is diagnosed late, it can result in serious infections and diseases.

This is why testing regularly for HIV is so important: to give you the confidence that you know your status and can protect your health and that of any sexual partners.

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CD4 and viral load

Immunity can be measured by counting CD4 levels in someone’s blood. This shows how HIV has affected their immune system, and how far the virus has progressed.

How much HIV is in someone’s body can be measured by counting their viral load. The higher the viral load, the more possible it may be for them to transmit HIV to someone else.

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HIV treatment

HIV medication is now extremely effective. It increases a person’s CD4 count and reduces their viral load to undetectable levels within about six months, meaning they can maintain a healthy immune system, and will not be able to pass on the virus through sex. This is known as U=U, Undetectable equals Untransmittable.

So although there is currently no cure for HIV, which a person will have for life, most people are nevertheless able to live a full and healthy life.

Find out more about HIV treatment

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How is HIV passed on?

HIV can be passed on through semen, vaginal fluids, rectal secretions, blood or breast milk.

You can get HIV from vaginal or anal sex without a condom, if you are not taking PrEP and your partner is living with HIV and has a detectable viral load. You can also acquire HIV if you share injecting drug equipment.

HIV can be passed on during pregnancy and birth, but when someone is on effective HIV treatment, the risk of HIV being passed on to their baby is just 0.1% (or one in a thousand). There is also a small risk of transmission from breast or chest feeding, but HIV medication makes this extremely unlikely.

 You can’t get HIV from:

  • Sex with a  partner who is living with HIV and is on treatment and has an undetectable viral load (learn more about undetectable equals untransmittable, U=U, via aidsmap)
  • Touching, hugging, shaking hands or sharing utensils
  • Kissing, spitting or sharing saliva
  • Urine or faeces
  • Scratching
  • Insect bites
  • Contact with a discarded needle
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Oral sex and HIV

What about oral sex?

Oral sex generally carries little to no risk of transmitting HIV. Saliva breaks down the virus and is an effective barrier to HIV. There is an EXTREMELY LOW risk if semen or vaginal fluid containing the virus enters the mouth, but ONLY where cuts, sores, or the presence of other sexually transmitted diseases provide a direct route into the blood stream of the negative person.

Reports of transmission through oral sex alone are extremely rare and often difficult to confirm.

Biting carries little to no risk of transmitting HIV as there is not enough HIV in saliva.

If a person with a detectable viral load had enough of their own blood in their mouth AND caused a deep enough wound to get that blood into the negative person’s bloodstream, there is an incredibly small risk that HIV could be passed on.

Similarly, sharing sex toys carries almost no risk of transmitting HIV, unless there is trauma and the presence of blood.

In all cases, if the person living with HIV is on effective treatment, or the negative person is taking PrEP, there is NO risk of HIV being passed on.

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HIV and travel

Some UK-born people diagnosed with HIV in the UK acquire the virus while they are abroad. Many countries have higher HIV rates than the UK, including countries in Sub-Saharan Africa, some parts of the Caribbean, Eastern Europe and South East Asia.

When travelling abroad, you should take the same precautions as you would at home, including taking PrEP, using condoms for sex and not sharing needles or drug equipment.

If you are living with HIV, many countries clearly state that your HIV status will not affect whether you can visit. Most countries do not require any type of medical test for short- or long-term stays. However, there are still some countries which do limit entry for people living with HIV.  For further information about HIV and travelling abroad, visit aidsmap.

I might have been exposed to HIV while abroad

 If you think you may have acquired HIV when you were abroad, seek local medical advice as soon as possible, and get tested when you get home.

Post-Exposure Prophylaxis (PEP), a short course of HIV treatment, can be taken if you are worried that you have acquired HIV. This treatment may stop you from getting HIV if taken within 72 hours after exposure. Access to PEP differs from country to country and may only be available in large cities rather than nationwide. Therefore you should not rely on this form of medication as protection from acquiring HIV.

 Advice while abroad

 For sexual health advice while you are abroad, you can call THT Direct: +44 808 802 1221

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Do you want to know more?

About HIV