Continuing Risks
Although it may be disappointing to hear, safe sex is essential even when both sexual partners are living with HIV. Why? The most obvious reason is that HIV is not the only sexually transmitted disease (STD) to which people are vulnerable. Individuals who are living with HIV can also be infected with other STDs, and having the disease can make some of these infections substantially worse.
Being simultaneously infected with HIV and another disease is known as co-infection. One particularly problematic type of co-infection occurs when someone is infected with both HIV and hepatitis C (HCV). An HIV/HCV co-infection is more difficult to treat and those who have it may have more severe health outcomes in both the long and short terms.
Unprotected sex between two people living with HIV is also risky even if both partners are otherwise STD-free and the relationship is mutually monogamous. This is because of the potential for an HIV superinfection. HIV superinfection occurs when a person who is already infected with HIV is exposed to and becomes infected with, a different strain of the virus.
Some studies have estimated that the risk of superinfection is similar to the rate of initial infection with HIV. Superinfection is problematic because it is associated with increased health problems and because it is harder to treat, even when using combined antiretroviral therapy, as there is a possibility that someone could be infected with two differently drug-resistant strains.
The fact that HIV superinfection is reasonably common also poses problems for vaccine research. It suggests that infection with one strain of HIV isn’t enough to protect patients from infection with another. That makes it less likely that a vaccine will be universally, or even widely, effective.
Does Treatment Matter?
If you and your partner are both living with HIV and both of you have your infections fully suppressed with treatment, you should discuss the risks of unprotected sex with your healthcare providers. Safe sex is still a very good idea, but treatment as prevention studies have shown that the risk of infection of a partner without HIV is zero when their regular sexual partner has an undetectable viral load.
NOTE: HIV superinfection should be distinguished from dual-infection, which is defined as being infected with two HIV strains at the same time. Although HIV superinfection can lead to dual infection, it is also possible for an individual to initially be infected with two strains of HIV.
doi:10.1097/QCO.0000000000000613
