Superinfection

About 50 cases of reinfection have been reported in the medical literature. However, there’s disagreement about how common it really is. Some researchers think it is very rare, but others believe much more common than the small number of case reports suggests.

Now, a Dutch study has failed to find any evidence of HIV superinfection in HIV-infected gay men who had unprotected sex.

The research involved 15 people. They had blood tests every three months to check for reinfection. Every six months, they were asked if they had had unprotected anal sex, or if they had been diagnosed with a sexually transmitted infection (STI).

All the men had either reported unprotected anal sex with two or more partners, or were diagnosed with a STI, in at least one six-month period. The men were monitored for an average of 5.8 years. No superinfections were detected.

The researchers do not regard their results as definitive and call for further studies into this matter. In particular, they speculate that the level of risk of the men in their study may not have been high enough to lead to superinfection.

But the research envisaged by the researchers may be difficult to conduct, especially because of the criminalisation of HIV transmission, or of non-disclosure of infection status, in many countries. People may be disinclined to provide frank information about their sexual behaviour, even where the inquiry relates to sexual behaviour with partners of the same HIV status.

However, it's important to remember that even if unprotected sex doesn’t lead to reinfection with HIV, there is still a risk of getting another STI or of being infected with hepatitis C.