Johns Hopkins study shows potential for chemical vaccine against malaria

Malaria was responsible for over 600,000 worldwide deaths in 2021

A study from the Johns Hopkins Bloomberg School of Public Health has provided evidence supporting the potential of an injectable chemical vaccine for malaria.

The study was led by researchers from the Johns Hopkins Malaria Research Institute, the Johns Hopkins University School of Medicine and the University of Liverpool.

Responsible for over 600,000 global deaths in 2021, malaria is a serious disease caused by a parasite that can lead to high fevers, shaking chills and flu-like illness.

Malaria parasites in infected patients being treated with an antimicrobial medication called Mepron (atovaquone) – which is commonly used as a malaria preventative in combination with an antimalarial called proguanil –  can develop resistance to the drug.

In the study, funded by Unitaid, the National Institutes of Health, the Johns Hopkins Malaria Research Institute and Bloomberg Philanthropies, the researchers found that the same genetic mutation that produces malaria parasites resistant to atovaquone could also destroy the parasite’s ability to live within mosquito hosts.

After investigating a key resistance mutation called cytochrome-b Y268S, the team discovered that the major malaria parasite, Plasmodium falciparum, carrying this mutation is significantly less susceptible to atovaquone.

Additionally, when using mosquitoes and P. falciparum-infectable mouse models, the researchers found that the Y268S mutation destroys the ability of P. falciparum to live within its Anopheles mosquito hosts, disabling its transmission.

Based on the findings, the researchers suggest that a ‘chemical vaccine’ to protect people against malaria using atovaquone has potential and should be further investigated.

Theresa Shapiro, professor, clinical pharmacology, Johns Hopkins University School of Medicine and professor in the W Harry Feinstone department, molecular microbiology and immunology, Johns Hopkins Bloomberg School, said: “These findings should reduce concerns about the transmission of atovaquone resistance with atovaquone therapy, particularly when it is used as a chemical vaccine.”

She added: “This may be the path atovaquone takes as a chemical vaccine.”