Serodiscordant Couple Overview

Definition and Risks

couple talking with doctor

The term serodiscordant couple is usually used to refer to relationships where one partner is living with HIV and the other is not. Technically speaking, however, it can be used for any relationship where one person's blood tests positive for a virus and the other's does not.

It is thus also often used to refer to couples where one person is living with herpes and the other is not, or where one is living with hepatitis and the other is not.

Word Origins

The term serodiscordant is made up of two roots:

  1. Sero—meaning blood
  2. Discordant—meaning different or non-matching

Therefore a serodiscordant couple is a couple who have different blood. More specifically, it's a couple who has different blood markers or blood tests for a particular disease.


Doctors and scientists working with infectious diseases, such as HIV and hepatitis C, spend a lot of time thinking about individuals in serodiscordant couples. This is because the uninfected partners in such couples are pretty much the definition of high risk. 

There is, at least in couples who are having sex, a known potential route of infection. That means that individuals in serodiscordant relationships are the perfect target for prevention interventions. 

Prevention and treatment interventions, such as treatment as prevention (TasP) and pre-exposure prophylaxis (PrEP), have often been targeted at members of serodiscordant couples because they are considered to be at high-risk of either acquiring HIV or passing it on.

These couples are also a great population in which to do treatment and prevention research. Many of the studies of new HIV prevention technologies have been performed in heterosexual and homosexual serodiscordant couples.

Why? Because doctors know that the uninfected individuals in these relationships are likely to be exposed to HIV, which gives them the biggest bang for their buck. They have the potential to observe larger effects while treating fewer people.

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