A common pill turns your blood into mosquito poison—and slashes malaria in the process.
A simple pill may be the latest breakthrough in the fight against malaria.
A
massive study across Kenya and Mozambique found that mass administration of
ivermectin—an antiparasitic drug—reduced malaria cases by 26%. The pill works
in a surprising way: it makes human blood deadly to mosquitoes, killing them
after they bite. This novel approach could complement traditional tools like
bed nets, which have lost effectiveness due to mosquito resistance. Even
better, communities reported fewer lice, scabies, and bed bugs—bonus benefits
from a single monthly dose.
Ivermectin Shows
Promise in Reducing Malaria Transmission
A safe
and widely available drug, ivermectin, has shown promise in reducing the spread
of malaria when given to entire communities. In the largest study of its kind,
known as the BOHEMIA trial, researchers found a 26% drop in new malaria
infections even when standard tools like bed nets were already in use. These
findings highlight ivermectin’s potential to serve as an added layer of
protection in malaria prevention.
The
study was led by the Barcelona Institute for Global Health (ISGlobal),
supported by the “la Caixa” Foundation, in collaboration with the Manhiça
Health Research Centre (CISM) and the KEMRI-Wellcome Trust Research Programme.
The results were published in The New England Journal of
Medicine.
Malaria
continues to be a major global health issue, with 263 million cases and 597,000
deaths recorded in 2023. Existing prevention tools such as long-lasting
insecticidal nets (LLINs) and indoor residual spraying (IRS) are becoming less
effective. This is largely due to mosquitoes developing resistance to
insecticides and changing their behavior to bite outdoors or during times when
people are not shielded by these methods. These challenges have created an
urgent demand for new approaches to stop the disease.
Ivermectin
tablets used for the BOHEMIA trial in Kenya.
Ivermectin’s
Unexpected Role in Fighting Malaria
Ivermectin
is typically used to treat neglected tropical diseases such as onchocerciasis
(river blindness) and lymphatic filariasis (elephantiasis). However, studies
have shown that it can also reduce malaria by killing mosquitoes that bite
people who have taken the drug. As resistance to insecticides increases,
ivermectin may offer a new and effective way to reduce transmission, especially
in areas where standard methods are no longer reliable.
The BOHEMIA
project (Broad One Health Endectocide-based Malaria Intervention in Africa),
funded by Unitaid, tested this idea through two large-scale Mass Drug
Administration (MDA) trials in regions with high malaria burden: Kwale County
in Kenya and Mopeia district in Mozambique. Researchers evaluated whether
giving a single monthly dose of ivermectin (400 mcg/kg) over three months at
the start of the rainy season could lower malaria transmission. In Kenya, the
program focused on children aged 5 to 15, while in Mozambique it targeted
children under the age of five.
Kenya Sees Clear
Impact from Ivermectin
In
Kwale County, Kenya, children who received ivermectin experienced a 26%
reduction in malaria infection incidence compared to those who received
albendazole, the control drug used in the study. The trial involved over 20,000
participants and more than 56,000 treatments, demonstrating that ivermectin
significantly reduced malaria infection rates—particularly among children
living further from cluster borders or in areas where drug distribution was
more efficient. Moreover, the safety profile of ivermectin was favourable, with
no severe drug-related adverse events and only mild, transient side effects
already seen with ivermectin in campaigns against neglected tropical diseases.
“We
are thrilled with these results,” says Carlos Chaccour, co-principal
investigator of the BOHEMIA project and ISGlobal researcher at the time of the
study. “Ivermectin has shown great promise in reducing malaria transmission and
could complement existing control measures. With continued research, ivermectin
MDA could become an effective tool for malaria control and even contribute to
elimination efforts,” Chaccour, who is now a researcher at the Navarra Centre
for International Development at the University of Navarra, adds.
“These
results align with the World Health Organization’s (WHO) criteria for new
vector control tools,” states Joseph Mwangangi, from the KEMRI-Wellcome Trust
Research Programme. “The findings suggest that ivermectin MDA could be a
valuable complementary strategy for malaria control, particularly in areas
where mosquito resistance to insecticides is a growing concern,” adds Marta Maia,
BOHEMIA’s lead entomologist from the University of Oxford.
Lessons and
Setbacks in Mozambique Deployment
In
contrast, the implementation of the Mozambique trial in the rural district of
Mopeia faced severe disruptions due to Cyclone Gombe (2022) and a subsequent
cholera outbreak, which significantly disrupted operations. “One of the most
important lessons we learned from the trial in Mopeia is that strong community
engagement is essential,” states Francisco Saúte, director of the Manhiça
Health Research Centre (CISM). “Building trust with local communities and
fostering close collaboration with the Health Ministry, National Malaria
Control Program, and local authorities was key to ensuring acceptance of the
ivermectin MDA.”
Collateral
Public Health Benefits Beyond Malaria
In
addition to reducing malaria transmission, ivermectin MDA offers significant
collateral benefits. The BOHEMIA team found an important reduction in the
prevalence of skin infestations such as scabies and head lice in the ivermectin
group in Mozambique, and the community reported a major reduction in bed bugs
in Kenya. These effects are particularly valuable when ivermectin is integrated
into existing delivery systems, maximising its impact on public health.
Toward a New Era
of Malaria Control Strategy
The
study is part of a larger global effort to assess ivermectin’s potential in
malaria control. The findings have been reviewed by the WHO vector control
advisory group, which concluded that the study had demonstrated impact and
recommended further studies. Findings were also shared with national health
authorities as they evaluate the potential inclusion of ivermectin in malaria
control programmes.
“This
research has the potential to shape the future of malaria prevention, particularly
in endemic areas where existing tools are failing,” concludes Regina
Rabinovich, BOHEMIA PI and Director of ISGlobal’s Malaria Elimination Initiative. “With its novel mechanism of action
and proven safety profile, ivermectin could offer a new approach using a
well-known, safe drug that can add to the effect of other mosquito control
tools available today.”
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