What is viral load?
When we’re talking about HIV, we often refer to viral load. This is a number that tells us the amount of HIV in a positive person’s blood.
The more HIV in the blood, the higher the person’s viral load will be. A high viral load can increase the chance of someone getting ill with HIV and means the virus can be transmitted through sex. An undetectable viral load means an HIV-positive person cannot pass on the virus.
The goal of HIV treatment is to reach an undetectable viral load. Lowering it can take a few months of effective treatment. Once your viral load is undetectable, it gives your immune system a chance to recover and reduces your chances of getting ill from HIV.
The results of viral load tests are given as a number per millilitre. This shows the amount of virus copies in a millilitre sample of blood. The result will look something like ‘500 copies/ml’. An undetectable viral load is any result under 20 copies/ml (often written as <20 copies/ml)
Undetectable = untransmittable
Someone who has HIV, who is using effective treatment and has an undetectable viral load for 6 months or more, cannot pass on the virus. This is known as U=U or undetectable = untransmittable. There is zero risk of HIV transmission through sex once someone has become undetectable.
When a person is undetectable, they will not need to use condoms to stop HIV transmission. However, being undetectable does not protect against other STIs.
