At the main public hospital in Blantyre, Malawi the facilities were basic. The health system was stretched with malaria, tuberculosis and HIV/AIDS cases, with some patients sleeping on the floor due to bed shortages.

It was 2018 and I was there with my colleague senior biostatistician Dr Elasma Milanzi to investigate the high rates at which pregnant HIV-infected mothers and breastfeeding mothers and their infants were dropping out of HIV integrated care providing antiretroviral therapy.

This is a deadly serious issue because without antiretroviral therapy, there is a 20-45 per cent risk of an HIV positive mother passing the infection on to their unborn child, and a 16 per cent chance of passing it on to their infant through breastfeeding.

Adherence to sustained antiretroviral therapy can substantially reduce HIV viral loads, significantly reducing the risk of mother-to-child transmission.

In fact, antiretrovirals can reduce the risk of sexual transmission to near zero.

In collaboration with University of Malawi public health researcher Professor Victor Mwapasa, we were able to analyse data from around 1000 HIV-positive mothers and their HIV-exposed infants from southern Malawi where the problem is most acute and HIV prevalence is around 17 per cent.

We found that despite mothers and infants having access to HIV-related treatments, once mothers received their infant's HIV test result, that infant was 70 per cent more likely not to attend care with their mother than infants that had no test results.

This means these infants could no longer be tested for HIV infection, which still had the potential to occur through continued breastfeeding (whether through breast milk or abrasions and similar on or near the nipples).

Even more alarmingly, among those infants who were tested and found to be HIV-positive, these infants were three times more likely to just stop attending HIV integrated care. Attempts to improve retention by SMS messaging local community volunteers failed to make a difference.

This means that many potentially infected infants are never being tested, suggesting that rates of HIV infection in Malawi are under-estimated. It also suggests that many HIV-positive infants are not receiving lifesaving antiretroviral therapies. Without antiretroviral therapy, 20 per cent of infants in sub-Sahara Africa will die before their first birthday and most will not reach their fifth birthday.

Overall, we found that within 18 months only 50 per cent of mothers were still attending appointments or integrated care.

The onset of COVID-19 has only worsened the situation. Lockdowns and border closes have hampered both the production and distribution of antiretrovirals. As a consequence, modelling predicts new child HIV infections in Malawi will rise by 162 per cent.

While the pandemic has elicited an unprecedented global response, HIV still remains a huge health problem. Around 38 million people were estimated to be living with HIV in 2019, of which 1.8 million were children younger than 15 years. During that year, there were 690,000 HIV-related deaths. Since the epidemic started in 1981, a total of 32.7 million people have died from the disease.

However, HIV is now a disease of low- and middle-income countries. In 2019, Africa accounted for 67 per cent of HIV infections worldwide, a staggering 25.6 million people. Of these, eastern and southern sub-Sahara Africa is the most affected with 20.7 million people infected, equating to nearly 1-in-25 people. A further 4.9 million HIV positive people live in western and central Africa, 5.8 million are in Asia and the Pacific.

In December 2020, the announcement that a new, long-acting injectable drug – cabotegravir – was highly effective in preventing HIV infection in women, was largely ignored by the media. That was despite it being announced by the high-profile Dr Anthony Fauci, head of the USA's National Institute of Allergy and infectious Diseases.

"I wanted the world to see with all due respect to the extraordinary stress and strain we're going through with COVID-19, HIV is still a very important disease," Dr Fauci said at the time.

In an attempt to reach zero mother-to-child transmission of HIV, the World Health Organization in 2011 introduced the Option B+ initiative involving prompt initiation of lifelong antiretroviral therapy in all HIV-positive pregnant and breastfeeding women. It has succeeded in dramatically reducing mother-to-child-transmission of HIV. In sub-Sahara Africa, mother-to-child-transmission rates have reduced to between 2 per cent and 25 percent depending on the mother's access to therapy.

Some countries including Armenia, Belarus, Cuba, Thailand, Malaysia and the Caribbean have reduced mother-to-child-transmission to zero, as a consequence of well-coordinated integrated services such as antenatal, immunisation, paediatric care, community and HIV healthcare and surveillance programs.

So what needs to happen in Malawi to encourage mothers and their infants to get tested and stay in treatment?

In resource-limited countries, it is clearly a challenge to efficiently implement HIV integrated services, especially in rural areas. When a parallel study interviewed women that had dropped out of integrated care, they discovered an unsupportive family environment was a contributing factor.

In other women, inconsistent and fragmented health care systems was a driving reason behind non-attendance. This mirrors findings from other resource-limited African countries including Kenya, Mozambique and Uganda where unreliable integrated HIV care is thought to be the main contributing factor for these countries failing to achieve zero mother-to-child-transmission of HIV.

On a ground level, the improved training of staff and increased counselling for mothers could make a difference, especially increased efforts to advise breastfeeding mothers of the future risk of transmission.

Ultimately however countries like Malawi need more resources. Malawi is one of the poorest countries in the world. Of Malawi's 17 million population, 70 per cent live below the income poverty line, and nine million are children, of whom 2.9 million are orphans or considered vulnerable.

But it isn't just about boosting supplies of therapies. Malawi and other countries in sub-Saharan Africa need to focus on retaining mothers in treatment because it works, and for that the region needs support to train more health professionals, widen health education and improve infrastructure.

There is no one magic solution, but solving the problem is simpler than it seems. We as a world just have to recognise it, and back it up with funds to help.

The work of Dr Reece and Dr Milanzi in Malawi was facilitated by Professor Rob Moodie, from the Melbourne School of Population and Global Health, University of Melbourne.

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