People living with HIV who have suppressed viral loads

Viral suppression is defined as <1000 copies/mL. Some countries use other thresholds (such as undetectable, <50 copies/mL or <400 copies/mL), and require adjustment for comparability with other countries and for monitoring the global 95-95-95 target. UNAIDS recommends that countries adjust for lower threshold detection This is done using the formula:

In this instance, y is the standard (1000 copies /mL) viral suppression level, t1, is the country's alternative threshold that was used, and ɸ is the region-specific adjustment factor. This adjustment will be done automatically in Spectrum, if required.

Viral load suppression may be reported from three data sources: (1) clinical and programme data; (2) nationally representative surveys (such as the Population-based HIV Impact Assessment [PHIA] and HIV drug resistance surveys); or (3) early warning indicators of HIV drug resistance surveys. Countries should report data from whichever source is most recent and nationally representative.

• Routine viral load suppression tests from people on antiretroviral treatment collected through clinical or laboratory registers or case surveillance

For the numerator. Countries should report the estimated number of people nationally who have suppressed viral loads during the reporting period if viral load testing coverage (i.e., the number of people routinely tested during the reporting period, as per WHO guidance, among all people on treatment) is 50% or greater.

Countries that report viral load testing coverage of less than 50%, should, in contrast, only report the number of routine viral load tests - but not the number where the viral load is below the threshold, because this then is not a good, representative estimate for the overall population on treatment. Countries still wishing to use viral load result data despite viral load testing coverage below 50% should discuss with UNAIDS, to determine whether the percentage of people suppressed in the tested population can be considered representative for the population on ART with no access to testing.

Countries should only include testing data that result from routine testing among those on treatment, and not targeted testing to a select subgroup of patients on treatment. For example, a person's results should not be included if testing was done prior to treatment initiation or for the reason of a suspected treatment failure. If viral load is tested repeatedly for a person within the year, only the last routine test result should be used.

For countries where annual viral load testing coverage is 50% or over, an estimated number of people with suppressed viral loads should be reported. This is calculated from the number suppressed among those tested, multiplied by the total number of people on treatment. This assumes that levels of suppression in the untested population are the same as those in the tested population. This assumption is supported by evidence from South Africa, which shows that although viral load information was frequently missing, estimates of viral suppression did not change substantially after adjusting for missing data.

Example: A country with an estimate of 100 000 people living with HIV has routine viral load tests for 12 000 of the 24 000 people receiving antiretroviral therapy. The viral load testing coverage is 50%, and the country deems the level of viral load suppression in the untested population to be like that among the tested population of people on treatment. Of the 12 000 people tested, 10 000 people have suppressed viral loads. The estimated national number of people living with HIV who have suppressed viral loads is 20 000 [(10 000/12 000) x 24 000].

Where viral load suppression in the untested population on treatment is likely to not equal that in the tested population, please contact UNAIDS for further discussion about approaches for estimating this count.

For the denominator. Estimation models such as Spectrum are the preferred source for the number of people living with HIV. UNAIDS will work with countries to develop a Spectrum model that matches the estimate of people living with HIV if national estimates other than those produced through Spectrum are used.

For more information on estimating the number of people living with HIV who are on treatment, as part of calculating the third 95, please see Indicator 2.2.

• Recent nationally representative population surveys (including household, acquired HIV drug resistance surveys or early warning indicators (EWI) survey of HIV drug resistance)

For the numerator. The proportion reported to have suppressed viral loads among people testing positive in the survey should be multiplied by the total number of people estimated to be living with HIV nationally to obtain the total number of people who have a suppressed viral load. This value may slightly overstate the number of people who are virally suppressed among those on treatment, since it will include some people who are not on treatment but naturally suppress the virus. If using data from an acquired HIV drug resistance survey, either the 12- or 48-month cohort data may be used. Data from early warning indicators should only be used to generate national aggregate statistics if:

a) all clinics in a country - or a random sampling of clinics - reported early warning indicators data that includes at least 70% of all people on ART from the sampled clinics.

OR

b) if convenience sampling of clinics was used, a national aggregate statistic can be reported if the data from the sampled clinics includes at least 70% of the eligible population on ART in the country (see page 8 of the Early Warning Indicators (EWI) annex - sampling guidance - see References below).

Note: Countries using survey data should still report on the number of people on treatment with routine viral load tests during the reporting period. Survey data should only be used if conducted in both children and adults.

For the denominator. Estimation models such as Spectrum are the preferred source for the number of people living with HIV. UNAIDS will work with countries to develop a Spectrum model that matches the estimate of people living with HIV if estimates other than those produced through Spectrum are used. For more information on estimating the number of people living with HIV who are on treatment as part of calculating the third 95 target, please see Indicator 2.2.