Nav: Home

Malaria vaccines based on engineered parasites show safety, signs of efficacy

May 20, 2020

Two vaccines for malaria based on genetically engineered malaria parasites have been found to be safe in humans and show preliminary signs of protection, according to a pair of new phase 1/2a clinical trials. Although further work is needed to determine their effectiveness, the new vaccines represent a promising approach to create a long-sought yet elusive vaccine for malaria. Drug treatments and interventions like mosquito nets have reduced the health burden of malaria over the past few decades, but the disease continues to pose a huge public health challenge in developing countries. The creation of a workable vaccine has been a major goal for researchers for 50 years, but most vaccine candidates have failed to show durable benefits in trials. Isaie Reuling and colleagues previously created a vaccine based on a genetically modified version of the malaria parasite Plasmodium berghei, which infects rodents but does not cause disease in humans; the parasite was modified to express a protein from the closely related Plasmodium falciparum, the primary cause of malaria in humans. Here, the scientists administered their vaccine to 24 healthy human volunteers, who tolerated the immunizations well and did not show any severe side effects. The vaccine delayed infections when the immunized volunteers were exposed to mosquitoes infected with P. falciparum, an effect that may result by blocking the parasite from invading liver cells, the researcher speculate. The authors also estimated the immunization would slash parasite loads in the liver by 95%, indicating it might provide some protection to individuals.

Taking a similar approach, Meta Roestenberg and colleagues conducted a phase 1/2a trial of their PfSPZ-GA1 vaccine, which uses a genetically weakened P. falciparum parasite. The authors tested various vaccine doses in 19 volunteers and saw that the vaccine was well-tolerated and safe. The research team then immunized 39 volunteers with either PfSPZ-GA1 or a control vaccine three times over 24 weeks and exposed the volunteers to controlled bites from mosquitoes infected with wild-type P. falciparum. Three volunteers showed complete protection, while others displayed signs of protection and delayed malaria infections compared to nine individuals who received a placebo vaccine. Reuling et al. and Roestenberg et al. say that more studies are needed before making definitive conclusions about the strength of their vaccines, but suggest their results merit further testing.
-end-


American Association for the Advancement of Science

Related Malaria Articles:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.
Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the Umeå University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.
Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.
New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.
Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.
Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.
Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.
Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.
Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.
The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.
More Malaria News and Malaria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.