HIV prevalence in pregnant women

The HIV status of pregnant women is vitally important for children, and HIV continues to be a major contributor to both maternal and child mortality. An inquiry into reported maternal deaths between 2012 and 2013 found that of the 87% of women who died and whose HIV status was known, 65% were HIV-positive.[1] This number dropped subsequently, to 40.5% in 2021, although HIV status was not known for another 12% of mothers who died.[2] HIV-negative deaths outnumbered HIV-positive deaths - a switch from what was found in the pre-lockdown years of 2017-19.

Of all children who died in hospital between 2012 and 2013, only 35% were known to be HIV-negative. Twenty-two percent were HIV-exposed, and a further 18% were HIV infected. The HIV status of the remaining 14% of children was not known.[3]

The HIV prevalence amongst pregnant women is the proportion of pregnant women (aged 15 – 49 years) who are HIV positive. The majority of children who are HIV positive have been infected through mother-to-child transmission. Therefore, the prevalence of HIV amongst infants and young children is largely influenced by the HIV prevalence of pregnant women and interventions to prevent mother-to-child transmission (PMTCT).

The PMTCT programme had a notoriously slow start in South Africa, with only an estimated 7% of pregnant women receiving HIV counselling and testing in 2001/02. Following legal action by the Treatment Action Campaign, the Department of Health was ordered to make PMTCT services available to all pregnant women, and testing rates increased rapidly in subsequent years. Since 2009 HIV testing has been almost universal.[4] An evaluation of the PMTCT programme showed that transmission rates had declined to as low as 2.6% by 2013.[5]

HIV prevalence is measured in the National HIV and Syphilis Prevalence Survey which targets pregnant women aged 15 – 49 years who attend a public health facility. The most recent publicly available estimate, for 2022, is a prevalence rate of 27.5%. HIV prevalence rates increased rapidly from 1% in 1990 when the first antenatal prevalence survey was conducted, to 25% by 2000 and 30% in 2005. The prevalence rate remained at around this level until 2019, after which it dropped slightly

Results are reported in five-year age bands. For many years, HIV-prevalence rates were consistently highest amongst women in their 30s (reaching a prevalence rate of 43% in 2013) followed by those in their late 20s & 40s. Since 2014, prevalence rates among women under 35 years have declined, while those among older women have increased. In 2022, the highest HIV prevalence rates among first ante-natal visit attendees was in the 40-44 year age group.

HIV prevalence rates have remained comparatively low amongst youth (15-24 years) and have continued to decline steadily. In 2022, the prevalence rate among 20-24 year-old pregnant women were 16.4% (down from 24.2% in 2012), while prevalence among 15-19 year-olds was 7.6% (down from 12.7% a decade earlier).

There are substantial provincial differences in HIV prevalence. KwaZulu-Natal has consistently had the highest antenatal HIV rates, with prevalence in excess of 36% since 2000 and over 40% between 2013 and 2019. In contrast, the Western Cape has had relatively low prevalence, although the rate increased by ten percentage points to 19% over the 14-year period after 2000 before dropping back to 16% in 2022. Other provinces with relatively low HIV prevalence are the Northern Cape and Limpopo, with HIV-prevalence levels at 15% and 19% respectively in 2022.

These inter-provincial differences are partly a reflection of differences in HIV prevalence between different racial and cultural groups. For example, male circumcision is believed to be a major factor explaining inter-regional differences in HIV prevalence within Africa,[6] and its prevalence differs substantially between South Africa’s provinces.[7] Other factors such as differences in urbanisation, migration, socio-economic status and access to HIV-prevention and treatment services could also explain some of the differences in HIV prevalence between provinces.

Although HIV testing is almost universal in public health facilities, the antenatal prevalence survey does not include pregnant women who attend private health facilities, or women who deliver at public health facilities without having made a booking visit. Women with higher socio-economic status (proxied by post-secondary levels of education) and those seeking antenatal care in the private health sector have a relatively low prevalence of HIV.[8] Thus the surveys, which are conducted only in public health facilities, are likely to over-estimate HIV prevalence in pregnant women generally.