In 2021, HIV was successfully suppressed in the bodies of around 63% of the close to eight million people living with HIV in South Africa. This is according to the latest outputs from Thembisa, the leading mathematical model of HIV in South Africa.
Big picture numbers
The model estimates that there were around 7.9 million people living with HIV in South Africa in 2021, which amounts to 13.5% of the population. This number is anticipated to keep rising in the coming years since the rate of new HIV infections remains significantly higher than the rate of HIV-related deaths. There was an estimated 198 000 new HIV infections in 2021 and around 52 000 HIV-related deaths.
Of the 7.9 million people living with HIV in the country in 2021, it is estimated that 93.7% have been diagnosed. This suggests that South Africa's massive HIV testing efforts over the last decade have largely been a success.
But while our HIV testing numbers are impressive, the picture is less rosy when it comes to helping people living with HIV to start and stay on antiretroviral treatment. Of the 7.9 million people living with the virus, around 5.5 million, or 69%, were taking antiretroviral treatment in 2021. Antiretroviral treatment is recommended for all people living with HIV and this percentage should ideally be closer to 100.
One alarming detail is that of the estimated 266 000 people who started taking antiretroviral treatment in 2021, 57 000, roughly one in five, had CD4 counts below 200 cells/mm3. A CD4 count of below 200 cells/mm3 indicates a significantly compromised immune system. This means that a significant number of people only start taking treatment once they are very sick.
When people are stable on antiretroviral treatment, the virus is typically suppressed to very low levels in their bodies - so much so that they become non-infectious. Among the 5.5 million people on antiretroviral treatment, around 91% were estimated to be virally suppressed in 2021. Of the entire 7.9 million people living with HIV, however, only around 63% are virally suppressed.
Women and men
The Thembisa model outputs show very clearly how the HIV epidemic is playing out differently in women and men. Broadly speaking, many more women are living with HIV than men, but men who are living with HIV are less likely to be on treatment and more likely to die of HIV-related causes.
In 2021, an estimated five million women (15 and older) and 2.7 million men were living with HIV. New HIV infections in women were close to double that in men - 124 400 in women compared to 63 500 in men.
Given that many more women than men are living with HIV, it is not surprising that more women are on treatment than men, but the extent of the difference is eye-opening. In 2021, an estimated 3.7 million women were on treatment, more than double the 1.6 million men. The difference in people newly started on treatment in 2021 is a little less stark - 159 000 women compared to 99 000 men.
While many more women are living with HIV than men, more men are dying of HIV-related causes. In 2021, around 27 500 men died of HIV-related causes compared to 22 200 women.
One HIV prevention intervention squarely focussed on men and boys, voluntary medical male circumcision, took a significant knock in 2020 as the COVID-19 pandemic resulted in the temporary shutting down or down-scaling of circumcision programmes. In each of 2017, 2018, and 2019 over 200 000 boys aged 10 to 14 were medically circumcised. This dropped to below 70 000 in 2020 but bounced back to over 200 000 in 2021. Older age groups saw similar drops in 2020 followed by solid recoveries in 2021.
HIV still a problem for infants and children
In 2021, it is estimated there were just over 8 300 cases of mother-to-child transmission of HIV. On the one hand, this is a dramatic improvement on the early 2000s when the number hovered at around 74 000. On the other hand, it seems remarkable that in 2022 something as preventable as mother-to-child transmission of HIV is still a substantial problem.
The details are interesting.
Of the over 8 300 cases of mother-to-child transmission in 2021, around 2 800 occurred at or before birth - the majority, 5 600, occurred during breastfeeding. One likely explanation for this is that some women are contracting HIV in the months after having given birth and then transmission to their babies takes place before they are diagnosed and their HIV viral load can be brought under control using antiretroviral therapy.
Either way, HIV in children remains far from over. Around 238 000 children (under the age of 15) were living with HIV in 2021.
Signs of PrEP scale-up
One of the most encouraging things in the new Thembisa outputs is the uptick it shows in PrEP usage in 2021 - albeit from a very low base. PrEP or pre-exposure prophylaxis refers to HIV-negative people taking antiretroviral drugs to prevent HIV infection. For now, PrEP is only available as a pill in the public sector but a vaginal ring and an injection administered every two months should also become available in the coming year or two.
PrEP coverage in sexually active individuals is estimated to have increased from 0.1% in 2019, to 0.3% in 2020, and to 1% in 2021. Coverage in sexually active women (1.3%) in 2021 was better than that in sexually active men (0.7%). Coverage was estimated to be much higher for groups that have been targeted for PrEP for a few years now, such as female sex workers (21.7%) and men who have sex with men (14%). Coverage in sexually active adolescent girls and young women was estimated to be 5.1% - a promising sign given the persistently high number of new infections in this group.
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COVID-19 sets back life expectancy
For most of the last two or so decades, HIV has been a key driver of life expectancy in South Africa. Life expectancy dropped precipitously from the mid-90s to 2004 because of HIV-related deaths and then recovered due to the rollout of antiretroviral treatment which prevented people living with HIV from dying. Outputs from the Thembisa model have always shown this dynamic very clearly.
The latest Thembisa outputs, however, also show how COVID-19 has temporarily derailed the upward trend in life expectancy. Having recovered from around 54 years in 2004 to 64 in 2019, the COVID-19 pandemic knocked life expectancy back to between 58 and 59 in 2020 and 2021.
Note: In this article, we quote outputs from Thembisa version 4.5 only up to 2021. There are also Thembisa outputs for 2022 and future years, although these are much more uncertain. We have rounded some of the numbers for easier reading. Low takes sole responsibility for any and all errors.
Technical note: In Thembisa outputs stock variables (e.g. total HIV infections, population size) refer to the middle of the year in question and flow variables (e.g. new HIV infections, AIDS deaths, and total births) cover the period from the middle of the stated year to the middle of the next year.
