Public health research and policy supports the idea of combination prevention, in other words the coordinated use of complementary strategies. The strategies should include behavioural interventions (e.g. education), biomedical interventions (e.g. testing) and structural interventions (e.g. legal equality for affected populations).Regular testing, condoms, PrEP and an undetectable viral load can be promoted together as part of combination prevention.

 

Synergies can work in a number of ways, for example:  If individuals test frequently at clinics where HIV treatment can be started immediately after diagnosis, those who are diagnosed will only be infectious for a short period of time.  

 

Using condoms and PrEP together provides protection against HIV and many other sexually transmitted infections (STIs). Preventing the spread of STIs is relevant to HIV prevention, as a number of STIs make HIV transmission more likely when prevention methods (condoms, PrEP or an undetectable viral load) are not in place.  People need to engage with sexual health care in order to be prescribed PrEP, facilitating regular testing for HIV and STIs, as well as access to behavioural support. 

 

For couples in which one person has HIV and the other does not, PrEP and treatment as prevention may both be used as prevention strategies, at different points in time. If the HIV-positive partner is not yet taking treatment or has only recently started, then PrEP can be provided to the HIV-negative partner.

 

Once the positive partner is stable on treatment, with an undetectable viral load for at least six months, then the couple can be confident that 'Undetectable = Untransmittable'. At this point, PrEP would no longer be needed, unless the HIV-negative partner needs PrEP for protection with additional partners outside this relationship.  The combination of PrEP availability and a greater understanding of 'Undetectable = Untransmittable' are reducing stigma towards people living with HIV, especially in sexual contexts.