Other reasons to expand testing

Several other prevention strategies depend on there being frequent testing and a high rate of diagnosis in the population.

Treatment: Clearly, amidst the debate on the merits and possibilities of using HIV treatment to prevent HIV, we must not lose sight of the fact that the primary aim of HIV testing must be to minimise time between infection and treatment, damage to the immune system and deaths due to AIDS and HIV-related conditions.

Monitoring and surveillance: The HIV-infection rate (incidence) is the ultimate measure of the success or failure of HIV-prevention activities in a country or area. New HIV diagnoses are only a surrogate measure for incidence, as changes in the diagnosis rate will tend to lag behind changes in incidence with a delay that reflects the average time between infection and testing. Nonetheless, there are ways of estimating incidence on the basis of successive rates of new diagnosis that have been used in San Francisco¹ and South Africa² and some countries, including France³ and the UK,⁴have now adopted incidence assays.

Behaviour change: There is evidence that many, if not all, people with HIV reduce their risk behaviour once they know their status, and some risk-reduction strategies, such as serosorting, are only possible if people have accurate knowledge of their own, and ideally their partners’, status.

Contact tracing: Tracing the contacts of people diagnosed is a standard method of attempting to limit the spread of other sexually transmitted infections and ill health caused by them, although in HIV it is hampered by questions of criminal liability and stigma.

Cost effectiveness: HIV tests are comparatively cheap, and when targeted at the appropriate population are cost effective or even cost saving.