Johns Hopkins Expert Warns Of Rising Malaria Threat Despite Vaccinations

Malaria is a life-threatening disease. It is primarily transmitted to humans through the bites of infected female Anopheles mosquitoes. The infection is caused by Plasmodium parasites and does not spread from person to person. Symptoms can be mild or life-threatening. While mild symptoms include fever, chills and headache, severe symptoms are fatigue, confusion, seizures, and difficulty breathing. Malaria can be prevented by avoiding mosquito bites and with medicines. Treatments can also stop mild cases from getting worse.

The World Health Organisation (WHO) recommends preventing mosquito bites with the help of nets, repellents and protective clothing. For maximum protection, WHO recommends administration of vaccines alongside a mix of other WHO-recommended malaria interventions such as bed nets and chemoprophylaxis.

However, recently Johns Hopkins experts have highlighted that vaccines alone won't help win the war against malaria.

Jane M. Carlton, PhD, is director of the Johns Hopkins Malaria Research Institute at the Johns Hopkins Bloomberg School of Public Health and a Bloomberg Distinguished Professor in the Department of Molecular Microbiology and Immunology at the School and in the Department of Biomedical Engineering at the Johns Hopkins Whiting School of Engineering, emphasising the ongoing burden.

"Malaria is one of the big 3 global infectious diseases... one of the deadliest and most burdensome in human history," Carlton said.

According to WHO data, there were 282 million cases of malaria in 2024, an increase of about 9 million cases (3%) compared with 2023. The estimated number of malaria deaths stood at 610,000 in 2024 compared to 598,000 in 2023.

The expert highlights that the WHO report has raised significant concerns about the resistance to antimalarial drugs and the ongoing efforts to control malaria and reduce its burden. Carlton pointed out that resistance to the last remaining effective artemisinin derivative antimalarial drugs has "very worryingly spread."

"Such resistance has now been confirmed in at least eight countries in Africa, and there are potential signs of declining efficacy of the drugs that are combined with artemisinin," she said.

WHO has identified biological factors that challenge malaria control efforts. These include the prevalence of malaria parasites with gene deletions, which can undermine the reliability of rapid diagnostic tests, and the invasion of Anopheles stephensi mosquitoes, which are resistant to many commonly used insecticides.

Expert highlights the following possible causes of the increase in infections and deaths:

• Drug resistance: The parasite is learning how to survive artemisinin, the world's leading frontline malaria medicine. This resistance is now spreading independently across Africa.
• Mosquito resistance: The mosquitoes that carry malaria are becoming immune to the insecticides used on bed nets.
• Invisible parasites: New mutant strains of malaria have evolved that can hide from standard rapid diagnostic tests, making them harder to detect and treat.

While two new vaccines (RTS, S and R21) are now being used, experts emphasise that they are not 100% effective. They prevent tens of thousands of deaths, but they aren't as powerful as other common childhood vaccines. Additionally, they require four doses to work properly, which is a major logistical challenge in poor or rural areas.

Promising tools and interventions

The World Health Organisation (WHO) has reported that new tools have significantly enhanced efforts to control malaria, potentially saving a million lives in 2024. Two breakthroughs are the world's first malaria vaccines, approved by the WHO in 2021 and 2023. Since their approval, 24 countries have incorporated these vaccines into their routine immunisation programs.

According to Carlton, "The vaccines are effective when used in combination with new bed nets and various treatment regimens, creating a multi-faceted approach to reducing the malaria burden."

Carlton also highlighted a new promising treatment in the antimalarial pipeline-ganaplacide/lumefantrine, known as GanLum. "It represents the first new drug class for treating malaria in over 25 years," she noted.

"It's time to eliminate this disease, and such a goal is within reach," she said.

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