Climate change impacts our health in myriad ways, from increases in vector-borne diseases to high mortality from heat waves. Changes in climactic conditions can affect us directly (via severe weather events, for example), or indirectly (such as by increasing pollen production in allergenic plant species and thereby increasing allergies). Until recently, though, there was little evidence of a connection between sexually transmitted diseases and climate change.

Last month, however, researchers from the Columbia Mailman School of Public Health published a new study that investigated the link between climate conditions in Lesotho and HIV. They combined climate data with information from a nationally representative survey to study the influence of a severe 2014-2016 drought on risk behaviors and HIV prevalence.

Their findings were striking; for young women in rural areas, drought was associated with earlier sexual debut, lower educational attainment, and higher HIV prevalence. For women in rural and urban areas, drought was associated with an increased likelihood of selling sex for money. The researchers found that recent migration and sexual behaviors such as inter-generational and transactional sex were strong predictors of HIV infection. On the other hand, higher educational attainment appeared to reduce the likelihood of HIV infection.

The authors speculate that these dramatic effects are due to the severe economic impacts of drought. During the study period, almost all of Lesotho experienced severe drought. Drought can destroy agricultural productivity, and force families to migrate and seek alternative income sources or engage in risky sexual behaviors. Economic shocks can also contribute to high drop out rates for girls, which can lead to early marriage or sexual exploitation and heightened HIV risk.


Severe drought impacted Lesotho during the study period in 2014-2016, when rainfall ranged from 1% to 36% of average rainfall amounts. From Low et al. (2019)

The lead author, Andrea Low, stressed the importance of building climate resiliency in an interview she did with Thomson Reuters Foundation. “We really need to think about the population in the long term…If that’s reduced every time there’s some kind of climate extreme and they have to pull their kids out of school, that is going to have really detrimental effects – not just on HIV but on all aspects of society,”.

The researchers suggest a number of other strategies to reduce the impacts of drought on HIV. In addition to efforts to stabilize school enrollment during drought periods, the study authors suggest that HIV treatment programs could specifically focus on areas hit by drought and food insecurity. These programs could even provide monetary support during droughts to reduce high risk sexual behaviors and migration, or preexposure prophylaxis to high risk groups.

Ultimately, better understanding and responding to the effects of climate change will be crucial in the fight against infectious diseases like HIV. As Low states, “I think the real concern is that we have gained a lot in terms of epidemic control … but there is always a possibility to lose all those gains if a lot of people are displaced due to climate extremes (and) forced migration”.



Article Citation:

Association between severe drought and HIV prevention and care behaviors in Lesotho: A population-based survey 2016–2017 
Low AJ, Frederix K, McCracken S, Manyau S, Gummerson E, et al. (2019) Association between severe drought and HIV prevention and care behaviors in Lesotho: A population-based survey 2016–2017. PLOS Medicine 16(1): e1002727.

Thomson Reuters Foundation News Article

Climate shocks threatens gains against HIV in Africa, researchers say. Lazareva, I (2019). Thomson Reuters Foundation News. 

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