Another study confirms that HIV-positive people on treatment and with very low levels of the virus in their blood can't transmit HIV. (Siphiwe Sibeko, Reuters)
The world has 18 months left to reach the targets United Nations member countries like South Africa signed up to in 2021.
The goals, which were set by the Joint UN Programme on HIV and Aids (UNAids), are there to keep countries on track to get new HIV infections down low enough by 2030 so that Aids is no longer a public health threat.
But most countries are off track.
And the cost of not turning this around, a study released at the 25th International Conference on Aids in Munich, Germany, shows, is nearly 35 million new HIV infections and 18 million people dying of Aids by 2050.
On the other hand, if countries spend money on doing the right things to stop people from getting infected with HIV, and also allow those who have the virus to stay healthy enough to work and therefore contribute to the economy, they will get a R270 ($14.80) return on each R18 ($1) they invest in a person. In other words, the money they spend on preventing new infections will be returned to them 15-fold in economic benefits.
So, what are the right things to do?
According to the study, which measured the cost of inaction in 114 countries, including South Africa, it means starting as many HIV-infected people as possible on treatment — and keeping them on it.
That’s also the case with the UNAids goals, which are called the 95-95-95 targets.
That simply means that, by the end of 2025, countries need to have diagnosed 95% of people with HIV, and of those, 95% need to be on treatment in the form of antiretroviral drugs (ARVs). From that group, 95% need to be virally suppressed, meaning they have such low levels of HIV in their bodies they’re unable to transmit the virus to others through sex.
By the end of 2025, the world needs to be down to 370 000 new infections a year to end the epidemic, UNAids calculated, but their report, released at the conference on Tuesday, shows the world had 1.3 million infections in 2023 — in other words, 3.5 times more than what we should have by the end of next year.
Where is South Africa at?
That’s tricky to answer, because the country uses four different ways to track this — and the numbers are not the same. Take, for example, the second 95 goal, which measures what proportion of people diagnosed with HIV are on ARVs.
The Human Sciences Research Council’s 2022 survey shows we’re at 91% and the National Institute for Communicable Diseases’ antenatal survey, conducted in the same year, says we’re at 99%. Moreover, the 2023 HIV investment case, produced by the Health Economics and Epidemiology Research Unit at the University of the Witwatersrand, says we’re at 84%, but the Thembisa model’s 2023 data estimates that we’re only at 78%.
Which set of data does the health department use to report to UNAids and which set of data is for what?
We break it down.
Know your numbers
The health department uses the numbers of the Thembisa model as the “basis for the HIV estimates that South Africa submits to UNAids [for their] Global Aids Monitoring [process]”, says Leigh Johnson, the lead developer of the data project, based at the University of Cape Town.
That’s because, although measured numbers are real, they can be counted only in a sample of people, while a model can give an estimate for a country’s whole population, making it easier to use the numbers to plan ahead. Actual numbers tell us what things look like now, or have looked like in the past, but they can’t tell us what things will look like in the future.
A data model is a set of calculations in which symbols, for example x, y and z, are used as placeholders for numbers of which the values can change. These placeholders are called variables (because their values aren’t fixed). By putting known numbers to these variables and then adding, subtracting, dividing or multiplying them in specific ways, you can work out the value of an unknown variable.
This means a model is a way to use maths to find out how things in a system work together to bring about a specific result. The numbers that come from a model are calculated rather than measured, though, so they’re estimates of what’s going on and what numbers could look like a few years ahead.
Yogan PIllay, who was the deputy director general at the national health department between 2008 and 2020 and who managed the department’s HIV targets during this time, says the agreement with UNAids is that South Africa uses the Thembisa model, rather than the Spectrum system like many other countries in sub-Saharan Africa because it is “based on South African data that is routinely collected, and over the years, we’ve found it to be more reliable [for us] than Spectrum”.
Spectrum is also a mathematical model, but its calculations and variables are set up somewhat differently from that of Thembisa.
Pillay is the head of HIV and TB delivery at the Bill & Melinda Gates Foundation.
The Thembisa model estimates that 95% of adults with HIV — people of 15 years and older — have been diagnosed. Of these, 78% are on ARVs and, of the ones on treatment, 91% are virally suppressed. According to these numbers, the country is a long way from reaching the second of the three targets.
But real-life studies are another way to get an idea of how well — or how badly — things are going.
Two such studies in South Africa are the Human Sciences Research Council’s (HSRC) National HIV Prevalence, Incidence and Behaviour survey and the 2022 Antenatal HIV Sentinel survey.
From the HSRC’s survey, in which about 70 000 people took part and about a third of them gave a blood sample to be tested, it looks as if South Africa is in a better position than what the Thembisa model shows — of the 90% of people with HIV who have been diagnosed, 91% are on treatment and 94% are virally suppressed.
Numbers from the antenatal survey, in which just under 38 000 pregnant women across South Africa participated, are even better. According to those figures, the country has already hit both the first two 95 targets and is at 91% for the third.
But the numbers are different from those of the Thembisa model, because in a survey, data is collected from a group of people from a certain population. For instance, the antenatal survey only counts HIV infections, diagnosis and treatment numbers in pregnant women, whereas the HSRC survey’s participants were from general households.
However, says Johnson, “models and surveys both have their place”.
Putting it all together
Real numbers from surveys such as that of the HSRC are used to calculate the Thembisa model’s figures. Because models are used to make predictions about the future, it’s important to make sure that the data that is used to calculate estimates is realistic and accurate, he says. “Using many different data sources in a single model helps to lower uncertainty [in the estimate].”
That’s why the model uses data not only from the latest HSRC survey, but also numbers from the five previous ones, going back to 2005. The survey was conducted in 2005, 2008, 2012, 2016 and 2017.
In turn, the HIV Investment case, which looks at how to get the best bang for our buck when trying to prevent new HIV infections, uses numbers from the Thembisa model, explains Johnson.
According to these figures, South Africa has hit the first target, but is at only 84% on the second and at 93% on the third. Because the Investment case usually comes out six to nine months after the Thembisa figures, on which it’s based, Johnson explains, “it might [therefore] not match the most recent [model] estimates”.
How do the estimates help?
While there are different numbers in South Africa for the 95-95-95 targets, what we do know is that “we have saturated the number of people who have tested for HIV at least once, but people need to be retested”, says Pillay.
“The big challenge has been to ensure that everybody who’s tested positive is initiated on ARVs and that they’re supported to stay on their medicine so they can remain virally suppressed.”
He says the best way to use 95-95-95 data to decide how the health department should use its resources is to also look at what the data says about progress in specific groups of people.
“The national averages do cover the discrepancies between women and men, and women, men and children, with the latter doing the worst,” Pillay explains.
For example, in 2023 almost twice as many new infections were in women than in men, and about 6 500 of the total number of new cases were among children. This means that if provincial health departments don’t spend more effort and money on preventing infections among, for instance women, it will prevent us from reaching the UN targets.
We’re not doing well with curbing new infections in general, says Pillay. The target is to, by 2030, have reduced new infections by 90% compared with 2010 figures. In 2010, South Africa had about 350 000 new infections, so the goal should be to have only 35 000 in 2030. In 2023, though, the country had 150 000 new cases — almost five times more than where we want to be.
Pillay concludes: “South Africa is failing on the second 95 target [getting people on treatment], and we see many still with advanced HIV disease. Data also shows us that people cycle in and out of treatment, which is another challenge because if they aren’t virally suppressed [from staying on their medicine] they can still transmit HIV to others.”
Yogan Pillay, the head of HIV and TB delivery at the Bill & Melinda Gates Foundation (BMGF), is quoted in this article. Bhekisisa receives funding from the BMGF, but is editorially independent. Read more about the nature of our donor relationships.
This story was produced by the Bhekisisa Centre for Health Journalism. Sign up for the newsletter.
