22 May 2020

In an innovative study, Radboudumc and LUMC jointly tested a candidate vaccine based on a genetically weakened malaria parasite. The results of this clinical trial, published in Science Translational Medicine, show that the vaccine is safe and elicits a defense response against a malaria infection.

Malaria is a major infectious disease, caused by a parasite with a complicated life cycle in humans and mosquitoes (see "About Malaria" below). The first stage in humans takes place in the liver, the second in the blood. Since the liver phase does not cause any symptoms of disease, but the blood phase does, the purpose of the vaccine is to stop the parasite in the liver.

Weakening malaria

For the malaria vaccine in this study, researchers made a weakened malaria parasite by removing two genes and developed it into a vaccine together with the American company Sanaria Inc. This parasite reaches the first liver stage in humans, but the genetic weakening means that it does not continue to later stages or lead to infection of the blood. In earlier phases of the research, important genes were identified that, in their absence, prevented the parasite from developing in the liver. In a joint clinical study, 67 volunteers in Leiden and Nijmegen received injections of the vaccine made from the genetically modified parasite (called PfSPZ GA1) – a first in the world for an injectable, genetically weakened malaria vaccine. A high and a low dose were administered.

Safe and partially effective

The results of the trial show that the vaccine is safe. It does not lead to infection of the blood and therefore does not cause malaria symptoms. It was also observed that the vaccinated volunteers developed an immune defense against a malaria infection, although this protection was not complete. This means that the disease is delayed but not prevented. According to the researchers, the measured immune responses and demonstrated safety are strong incentives to further develop a vaccine based on genetically attenuated malaria parasites.

About malaria

Malaria is one of the major infectious diseases of our time with around 216 million cases and 400,000 deaths annually. In recent years there has been an increase in the number of infections, especially in Sub-Saharan Africa and South America.

The most deadly form of malaria is caused by a single-celled parasite, Plasmodium falciparum, which is transmitted by mosquitoes. Once in humans, the parasite first develops in the liver for about seven days. The parasite transforms and shifts from the liver into the blood where it can infect red blood cells. Subsequently, the parasite develops from asexual cells into mature male and female germ cells which can then be sucked up by mosquitoes, after which fertilization of the parasites takes place in the mosquito stomach. The offspring can return to humans after another mosquito bite.
 
 
 

Related news items


BCG vaccine is safe with no increased risk of COVID-19 symptoms says Mihai Netea

11 August 2020

The BCG vaccine has a general stimulatory effect on the immune system and is therefore effective against multiple infectious diseases - possibly also against COVID-19.

read more

650,000 Euro funding for research into the phasing out of medication for leukaemia patients

30 July 2020

With a 650,000 euro funding from ZonMw, researchers from the Haematology and Pharmacy departments can develop a medication phasing out strategy for patients with chronic myeloid leukaemia. This strategy will be tested in practice.

read more

Increased role of patients after bowel cancer treatment

30 July 2020

Approximately 14,000 patients get colorectal cancer every year. Almost all patients are operated on and monitored afterwards (follow-up). In 2019 Radboudumc started a new approach to follow-up research after the treatment of stage II/III colorectal cancer.

read more

ERC Proof of Concept grant received by Ronald van Rij

30 July 2020

Ronald van Rij, theme Infectious diseases and global health, received an ERC (European Research Council) Proof of Concept grant of 150,000 euros, in order to make arbovirus vaccines even safer.

read more

Hypatia fellowship Call is open

30 July 2020

The Hypatia fellowship round with the deadline 31 May has been canceled. Therefore, the next available deadline will be 27 September 2020. Radboudumc researchers are invited to scout young potentials to fill the strategic gaps within the research themes imbedded in RIHS and RIMLS.  

read more

Mihai Netea and colleagues published two papers back-to-back in The Journal of Clinical Investigation. 

29 July 2020

These back-to-back articles investigated the effect of BCG vaccination on trained immunity. The first article shows that BCG vaccination inhibits systemic inflammation, depending on gender. The second article demonstrates that the circadian rhythm influences the induction of trained immunity.

read more