Treatment training for advocatesReinfection is where someone who is already diagnosed with HIV becomes infected with, a second, different strain of HIV.
There have been many reports of cases of reinfection with HIV.
The reason that this is controversial, is that for many years it was assumed that once you had been infected with HIV, reinfection was not a risk.
It is still not clear how often reinfection occurs, or what the risk factors for reinfection are.
Most studies suggest that the risk of reinfection are likely to be similar to the original risk of infection. It may be much lower than this. Viral load is probably the most important risk factor for transmission, with very high viral loads having the highest risk.
Although reinfection was first reported in recently infected people, cases have also been reported in chronic infection.
They included examples where someone on treatment has been reinfected by someone with drug resistant HIV, and where the treatment then stopped working.
This is the real risk of reinfection.
Two people with the same non-resistant virus, or with the same resistant virus would not risk the same difficulties from reinfection, as someone who is reinfected with drug resistant virus.
If two HIV-positive people have the same virus and the same resistance, then reinfection is unlikely to directly affect either their health or the effectiveness of treatment.
If one of the partners develops drug resistance on treatment, this would change this risk.
Further reading