Treatment training manual

2. 7 Reinfection with HIV

Reinfection is when an HIV positive person is infected with a second strain of HIV.  

This is sometimes called superinfection.

Although this is nt a high risk, reinfection can affect ART if the second infection is resistant to HIV drugs.

It is not clear how often reinfection occurs but it helps to think of two issues separately.

  1. The risk of having several distinct infections.
    Everyone who is HIV positive already has many different types of HIV. This is because HIV makes mistakes then it replicates. So the longer someone is positive without treatment, the more variations they have. These are all still small differences.Most studies think the risk of reinfection is similar to catching HIV the first time. Viral load is probably the most important factor. A very high viral load will have the highest risk.
  2. The risk that one of these will have different drug resistance.
    This is more rare, but depends on rates of drug resistance in your country. For example, in some countries 1 in 10 people diagnosed (10%) has drug resistance. The major risk from drug resistance is that it can stop your ART working.

Although reinfection was first thought to only be a risk during early infection, cases have also occured in chronic infection. This includes when someone on ART is reinfected with drug resistant HIV.  Drug resistant HIV can also reduce the effectiveness of PrEP and PEP (for prevention).

There is no risk from reinfection if two people are already likely to have the same strain of HIV. Ideally, both with be on ART with undetectable viral load. But if one partner becomes resistant due to low adherence, in theory, their partner could be reinfected with drug resistant HIV.

There is also no risk of reinfection if your partner has an undetectable viral load. Just as with any other case of HIV transmission, thr risk is related to viral load levels. U=U means that having an undetectable viral load means HIV sexual transmission doesn’t occur.

This is a good reason to look after both you and your partners health with good adherence.

Further reading

Link to page of questions and answers about reinfection.

Last updated: 1 January 2023.