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Unprotected sex and HIV

an African man and woman kissing

For someone to get HIV, an infectious fluid such as blood or semen has to get inside their body – usually during sex.

This can happen if the person with HIV has a detectable viral load and no form of protection is being used – this is called unprotected sex.

If someone with HIV is taking HIV medication and has an undetectable viral load they cannot pass on HIV.


When is a person with HIV infectious?

Someone with HIV is infectious if they have a detectable viral load.

This is often during the first few months after infection when they have very high levels of the virus in their body fluids and may not yet have been diagnosed.

Early diagnosis means you can start treatment to protect your health and reduce your viral load to undetectable levels.


How is HIV passed on during unprotected sex?

During sex body fluids from someone with HIV can get inside a person who is HIV negative through the following body fluids:

  • blood
  • semen (including pre-cum)
  • vaginal fluid
  • anal mucus

If the person with HIV has a detectable viral load this allows the virus to enter the HIV negative person’s bloodstream. This can happen during vaginal and anal sex (and sometimes oral sex too though this is much less common).

It can also happen when an object (eg, a sex toy) that has infectious body fluids on it is put inside an HIV negative person.


What is protected sex?

Protected sex means using a male or female condom during sex if one of you has HIV and a detectable viral load.

Condoms should be used with water-based lubricant as oil-based lube weakens them.

HIV treatment is also a form of protection.

How HIV treatment stops HIV being passed on:

  • A person with HIV who is taking treatment and has an undetectable viral load cannot pass on HIV.
  • Pre-exposure prophylaxis (PrEP), when taken correctly, significantly reduces the chances of becoming HIV positive. PrEP is a course of HIV drugs taken by an HIV negative person to lower the chance of infection.
  • Post-exposure prophylaxis (PEP), when started in time, can stop HIV infection after sex without a condom (or other exposure) with someone who is infectious - but it does not work every time. PEP is a month-long course of HIV medication taken by an HIV negative person after possible exposure to reduce the chance of getting HIV.

It’s also important to remember that if you have sex without a condom other sexually transmitted infections (STIs) can be passed on.


How risky is it to have unprotected sex?

An infection doesn’t happen every time unprotected sex takes place with someone who has HIV and a detectable viral load, but it could happen any time it takes place.

The more people someone has unprotected sex with, the greater the chance one of them might have HIV with a detectable viral load and the greater chance of you becoming infected.

Sex without a condom can also result in an unplanned pregnancy if other contraception is not being used.


Are some types of unprotected sex more risky than others?

Having unprotected sex with a person who does not know their HIV status carries a risk because people with undiagnosed HIV will not be on treatment.

However, different types of sex carry different risks of transmission. Millions of men and women around the world have got HIV through vaginal sex.

Anal sex without a condom has an even greater HIV risk because the lining of the rectum is not as tough as that of the vagina, so it is more likely to bleed during sex.

Oral sex is low risk (but not no risk).


Telling your partners about your HIV status

If you’re having protected sex there’s no law saying you must tell people that you have HIV - it’s your choice whether you tell your sexual partners.

However, in England and Wales there is a risk of being prosecuted for reckless transmission of HIV if:

  1. you had sex with someone who didn’t know you had HIV
  2. you knew you had HIV at that time
  3. you understood how HIV is transmitted
  4. you had sex without a condom, and
  5. you transmitted HIV to that person.

The law in Scotland is largely the same, except that a case can also be brought if transmission hasn’t taken place but someone has been put at risk of transmission without their consent or knowledge.

More about transmission laws in the UK ››


Microbicides and PrEP ››

 

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The Information Standard: Certified member

This article was last reviewed on 31/1/2017 by Anna Peters

Date due for the next review: 31/1/2020

Content Author: R. Scholey

Current Owner: Kerri Virani

More information:

BASHH/BHIVA PEP guidelines: UK guidelines for the use of Post-Exposure Prophylaxis following sexual exposure, 2015

Michael Carter, Primary Infection, NAM (2011)

Withdrawal and the risk from pre-cum, NAM (2011)

HIV risk levels for the insertive and receptive partner in different types of sexual intercourse, NAM (2011)

Anal intercourse, NAM (2011)

HIV transmission and the criminal law, NAM (2011)

Sexual Activity Without Condoms and Risk of HIV Transmission in Serodifferent Couples When the HIV-Positive Partner Is Using Suppressive Antiretroviral Therapy, Journal of the American Medical Association: Alison J. Rodger, MD; Valentina Cambiano, PhD; Tina Bruun, RN; Pietro Vernazza, MD; Simon Collins; Jan van Lunzen, PhD; Giulio Maria Corbelli; Vicente Estrada, MD; Anna Maria Geretti, MD; Apostolos Beloukas, PhD; David Asboe, FRCP; Pompeyo Viciana, MD1; Félix Gutiérrez, MD; Bonaventura Clotet, PhD; Christian Pradier, MD; Jan Gerstoft, MD; Rainer Weber, MD; Katarina Westling, MD; Gilles Wandeler, MD; Jan M. Prins, PhD; Armin Rieger, MD; Marcel Stoeckle, MD; Tim Kümmerle, PhD; Teresa Bini, MD; Adriana Ammassari, MD; Richard Gilson, MD; Ivanka Krznaric, PhD; Matti Ristola, PhD; Robert Zangerle, MD; Pia Handberg, RN; Antonio Antela, PhD; Sris Allan, FRCP; Andrew N. Phillips, PhD; Jens Lundgren, MD
JAMA. 2016;316(2):171-181. doi:10.1001/jama.2016.5148

Viral load, Michael Carter, Greta Hughson, NAM, Aidsmap, March 2014

More confidence on zero risk: still no transmissions seen from people with an undetectable viral load in PARTNER study, Gus Cairns, NAM Aidsmap, July 2016

Open your eyes to STIs, NHS Choices,l Nov 2015

When sex goes wrong, NHS Choices, Nov 2015

What is the life expectancy for someone with HIV?, NHS Choices, May 2015

HIV and AIDS treatment, NHS Choices, Sept 2014

Pre exposure prophylaxis, Roger Pebody, NAM Aidsmap, October 2016

Can post-exposure prophylaxis (PEP) stop me getting HIV?, NHS Choices, Sept 2015

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