HIV and AIDS CAUSES

Most cases of HIV are caused by having sex with a person who has HIV without using a condom.

A person with HIV can pass the virus on to others even if they do not have any symptoms. People with HIV can pass the virus on more easily in the weeks following infection.
HIV treatment significantly reduces the risk of someone with HIV passing it on.

Sexual contact

Most people diagnosed with HIV in the UK acquire the virus through unprotected vaginal or anal sex.

It may also be possible to catch HIV through unprotected oral sex, but the risk is much lower.

The risk is higher if:

• the person giving oral sex has mouth ulcers, sores or bleeding gums
• the person receiving oral sex has recently been infected with HIV and has a lot of the virus in their body, or another sexually transmitted infection

Who's most at risk?

People who are at higher risk of becoming infected with HIV include:

• people with a current or previous partner with HIV
• people with a current or previous partner who is from an area with high HIV rates
• people who are from an area with high HIV rates
• people who engage in chemsex (using drugs to help or enhance sex)
• men who have unprotected sex with men
• women who have unprotected sex with men who have sex with men
• people who inject drugs and share equipment
• people who have unprotected sex with somebody who has injected drugs and shared equipment
• people who share sex toys with someone infected with HIV
• people with a history of sexually transmitted infections, hepatitis B or hepatitis C
• people who have had multiple sexual partners
• people who have been raped
• people who have received a blood transfusion, transplant or other risk-prone procedures in countries that do not have strong screening for HIV
• healthcare workers who could accidentally prick themselves with an infected needle – but this risk is extremely low
• babies born from a parent with untreated HIV