5000 vertical HIV transmissions in India in 2021

The rate of vertical transmission of HIV in India (from mother to the baby) has reduced from over 40% in 2010 to 24% in 2021. Still, unless the full package of evidence-based interventions that reduce vertical transmission are properly implemented, it will be difficult to meet the elimination targets – which are to reduce the transmission rate to below 5% in breastfeeding populations and below 2% in non-breastfeeding populations, by 2025. (The original 2020 goal has been changed to 2025).

An important modelling study published last year in PLOS Global Public Health shows that in 2021 around 5000 new cases of vertical transmission were estimated to occur in India, with 58% of them happening during pregnancy or immediately after childbirth (the perinatal period) and the remaining 42% occurring during breastfeeding (the postnatal period).

“These are the first disaggregated estimates of the vertical transmission of HIV acquired during pregnancy, delivery and breastfeeding in India,” co-author Dr Sanjay Mehendale, who co-chairs the HIV estimation and surveillance group at India’s AIDS programme, told aidsmap. These estimates were ‘disaggregated’ in three ways: firstly, between transmissions occurring during the perinatal period and postnatal period; secondly, between those on and off antiretroviral therapy; and thirdly, by state.

Sixty-four per cent of HIV-positive pregnant women in India were on antiretroviral therapy in 2021. The study showed that 57% of vertical transmissions are estimated to take place among those who did not get antiretroviral therapy, 19% among those who were not able to continue with antiretroviral therapy, and 18% who acquired HIV during pregnancy or breastfeeding.

This study included all 17 high HIV burden states in India (where adult HIV prevalence was over 1% or where the number of people living with HIV was over 50,000).

Just as the human development index varies state by state in India, there are significant variations in vertical HIV transmission rates too. One in five vertical transmissions was estimated to take place in Bihar (950) followed by Uttar Pradesh and Maharashtra (600 each), Andhra Pradesh (400), Karnataka (325), Telengana and Odisha (200 each), Gujarat and Manipur (150 each), Delhi, Nagaland and Rajasthan (120), and West Bengal (100). The rest of the states had less than 100 transmissions each.

Antenatal care visits

In India every pregnant woman is expected to have at least four visits for antenatal care during her pregnancy. An HIV test is offered once – preferably during a visit in the first trimester of the pregnancy – and those found positive are offered treatment. If antenatal visits are started later in pregnancy or are less regular, then this limits the opportunities to offer the complete package of services, including HIV testing and (if necessary) antiretroviral treatment.

However, India’s National Family Health Household Survey shows that in some states of India, like Nagaland and Bihar, only half of the pregnant women have an antenatal visit in the first trimester of pregnancy. India’s national average was 70%. Similarly, the lowest rate of mothers who had made at least four antenatal care visits was in Nagaland (21%) followed by Bihar (53%), while the national average was 58%.

Prompt HIV diagnosis is a critical entry point to access services for reducing the risk of vertical transmission. Eighty four per cent of pregnant women took an HIV test in 2021. While this is three times more than those who took a test in 2012-2013, the goal is to achieve at least 95% HIV testing of pregnant women in India.

Out of the 17 high HIV burden states covered in the study, 14 of them had less than 80% pregnant women getting tested for HIV. Many reported a much lower number of pregnant women getting an HIV test (52% to 75%).

Hospital-based birth

Nagaland also had the lowest rate of births in hospital, followed by Bihar, Manipur, Uttar Pradesh, and Mizoram (below the national average of 89%) as per the National Family Health Survey. While Tamu Nadu had the highest hospital-based child birth rate (99.6%), it had the lowest rate of vertical transmission (10%). Hospital-based child birth and full provision of antenatal care package is indeed key.

There were many states where the vertical transmission rate was estimated to be higher than the national average of 24%: it was more than 30% in Bihar, Delhi, Manipur, Nagaland, and Odisha. It was between 22–28% in Maharashtra, Mizoram and Uttar Pradesh.

At least two-thirds of vertical transmissions in Bihar, Maharashtra, Manipur, Nagaland and Odisha were estimated to be among HIV-positive mothers who did not receive antiretroviral therapy during pregnancy or breastfeeding. Andhra Pradesh, Delhi, Karnataka and Uttar Pradesh were other states where more than half of the vertical transmissions were among HIV-positive mothers who did not receive the treatment.

“We have been able to increase the number of hospital-based deliveries,” Dr Mehendale told aidsmap. “But does that mean that we have been able to increase the coverage of antenatal care services also? I think that is where the gap exists.”

Repeat HIV testing

It is estimated that 18% of all vertical transmissions in India involve mothers who acquired HIV during pregnancy (3.7%) or breastfeeding (14.7%). The World Health Organization recommendation of repeat HIV testing during pregnancy and breastfeeding should be implemented as the risk of vertical transmission is highest among those women who get infected during this period – as high as a 27% risk when mothers acquire HIV while breastfeeding. Offering HIV testing only once during pregnancy is not enough.

The study authors stress this point: “Studies in diverse settings, including in India, have demonstrated repeat HIV testing in the third trimester, during labour and/or during breastfeeding among women who tested HIV negative in the first test as a cost-effective strategy.”

Syphilis testing

The Indian government’s goal is to eliminate vertical transmission of both HIV and syphilis by 2025. Syphilis in pregnancy can result in stillbirth, early neonatal death, delivery before the due time, or birth of a baby with low weight or serious neonatal infection. However, syphilis testing rates are lower than HIV testing rates among pregnant women in India: around 60% in 2021- 2022, which has gone up to 71% in 2022-2023. So, syphilis testing needs to catch up too.

Dr Mehendale told aidsmap that the vertical transmission rate in India has further dipped from 24% in 2021 to 19.9% in 2022. But to bring it down to below 5% for eliminating vertical transmission will require full and effective implementation of the entire package of antenatal care services nationwide – and tailored policy and interventions for each of the high HIV burden states, as informed by the study.