Can people be re-infected with different strains of HIV?
Are there different types of HIV? If so, can an HIV positive person be infected with a different strain of HIV if they have unprotected sex?
Thank you for your question.
There are two main types of HIV, HIV-1 and HIV-2. HIV-2 is mainly found in West Africa and is harder to get and progresses much slower. HIV-1 is the most common type of HIV. Within each types there are lots of sub-groups.
Re-infection is only a problem when resistance to HIV medication is involved. If someone has HIV that is not resistant to any HIV medications then it is possible they can be re-infected with a virus which is resistant to one or more HIV treatments.
Alternatively, if someone is a long-term non-progressor, which means that they are able to maintain their HIV infection over a long period without needing treatment then it is possible they can be re-infected with another strain of HIV which progresses at a quicker pace.
For more information on some individual case studies of reinfection please follow this link.