Climate change is affecting HIV epidemics in Africa

Severe drought has been linked to increased HIV rates among young women in Lesotho, according to a new analysis by ICAP at the University of Colombia, USA and published in PLOS Medicine.

Using data collected as part of the Lesotho Population-Based HIV Impact Assessment (LePHIA), a national HIV survey of 12,887 people conducted in 2016 and 2017, the researchers also found that young women aged 15 to 24 in areas affected by drought were more likely to have earlier first-time sex, transactional sex and were less likely to stay in school. 

The Presidents Emergency Plan for AIDS Relief (PEPFAR) funded PHIAs seek to measure the reach and impact of HIV programmes in countries and are led by ICAP, the US Centers for Disease Control and Prevention (CDC), and the Ministry of Health in each country.

Previous research had estimated an 11% higher HIV incidence after periods of rain shortfall had negatively affected income generation across the region resulting in changes to human behaviour. More specifically, women may be less worried about protecting themselves from HIV in times of food insecurity, as they may instead choose to focus on getting food on the table.

There are other concerns around food insecurity as they relate to antiretroviral adherence, or even drug absorption in the body in times of malnutrition, which can, in turn, lead to increases in community viral load, drug resistance and onward transmission of HIV.

Despite these concerns, climate change policies do not often include any measures to intensify HIV treatment and prevention programmes.

In Lesotho, an estimated 55% of the population grow their own food and depend on rain-fed irrigation for their crops. Between 2014 and 2015, an El-Nino-led drought hit Southern Africa, resulting in food shortages for almost 40 million people in the region. In Lesotho, maize production fell by 67% and 25% of the population was in need of emergency food.

As a quarter of the population in Lesotho are living with HIV, understanding the effect of climate ‘shock’ on large-scale HIV programming is critical to ensuring their successful roll-out, and particularly in the era of ‘treat all’.

The researchers paired geospatial data on accumulated rainfall from 2014 to 2016 with data from the survey to determine if there were any associations between drought and HIV outcomes. Living in a drought area appeared to be associated with greater HIV prevalence in young females and was associated with a lower HIV prevalence in young males.

In their discussion, the authors state that in times of drought, families will adopt extraordinary measures to ensure they can secure food. Women are most vulnerable during these time periods. Girls, particularly in rural locations, will be married off earlier than usual for a bride fee – which is consistent with the results showing earlier sexual debut and higher school drop-outs. Increases in transactional and commercial sex behaviours were also found, and both are independently associated with HIV.

Reassuringly, the impact on viral load suppression was minimal in this study, thanks in part to the targeting of food packages to people on antiretroviral treatment. But concerns over the migratory nature of Lesotho’s population mean that some data may not have been adequately captured by the surveys.

The authors state that interventions to reach vulnerable populations during a drought could include, pre-exposure prophylaxis (PrEP) for migrants and young women, in addition to socio-economic programmes such as cash transfers. They call for more research to be conducted outside of Lesotho, and particularly the impact on young women elsewhere.

"This is the first paper to link climate shock to an HIV epidemic since antiretroviral drugs became more widely available in sub-Saharan Africa," said Jessica Justman, MD, senior technical director of ICAP at Columbia University and principal investigator of the PHIA Project. "We should view this as another kind of warning that climate change will affect us in unexpected and unwelcome ways."