Viral load testing shows the amount of HIV in the blood of a person living with the virus. Antiretroviral drugs suppress HIV replication. If a person on ARV treatment has a viral load above a certain point, it indicates that the treatment isn’t working, either because the medicines aren’t being taken correctly, or that HIV has become resistant to the antiretroviral medicines.

In either case, health workers can respond quickly, working with people on treatment to improve adherence to a drug regimen or prescribing advanced ‘second-line’ drugs. These steps can bring viral load down to virtually ‘undetectable’ levels, helping those on treatment stay healthy and benefiting thecommunity by reducing the risk of transmission. Sexual transmission of HIV is 96 per cent less likely when viral load is undetectable.

Viral load testing is the gold standard for monitoring the health of people on HIV treatment. But because the equipment can be expensive and requires skilled staff, the test is not widely available in poor countries with limited resources.

MSF – thanks to co-funding from UNITAID – is working to develop ways to expand viral load testing in these countries, using methods which are more affordable and call for less extensive training. These pictures offer a glimpse of MSF viral load and HIV treatment projects in Malawi, where the HIV adult prevalence is high at about 14-16 per cent.