Malaria: Vaccine clinical trial for pregnant women yields promising results

February 04, 2020

According to the World Health Organization, malaria is responsible for over 400,000 deaths each year. Despite the progress made in fighting the disease in recent decades, some populations remain particularly vulnerable. One such population is pregnant women.

In the areas of the world where malaria is endemic, people acquire immunity throughout their childhood, meaning that they are generally protected against its most severe outcomes once they reach adulthood. However, pregnant women are an exception because the red blood cells infected with the Plasmodium falciparum parasite responsible for malaria accumulate in the placenta, promoting anemia and gestational hypertension. The disease is also linked to a higher risk of spontaneous abortion, premature birth and intrauterine growth delays which lead to low birth weight and a high rate of neonatal mortality. In Sub-Saharan Africa, 11 million pregnant women were infected with malaria in 2018, with around 900,000 of their babies born underweight.

To tackle this public health problem, a team of researchers from Inserm and Université de Paris led by CNRS Research Director Benoît Gamain has spent the past two decades developing a vaccine for gestational malaria. The goal is to prevent the deaths of up to 10,000 mothers and 200,000 babies each year. "Developing an effective vaccine for young women before their first pregnancy is a priority if we are to reduce malaria-related mortality. An effective strategy could focus on a population similar to that targeted by HPV vaccination, for example, before the women become sexually active", emphasizes Benoît Gamain.

A safe and effective vaccine

Called PRIMVAC, the vaccine had recently been produced in large quantities in accordance with current regulations. In a clinical trial published in Lancet Infectious Diseases, the researchers provide data on its safety and ability to induce an appropriate immune response, up to 15 months after the initial vaccination.

The vaccine was evaluated in 68 non-pregnant women aged 18 to 35 at the Cochin Pasteur Clinical Investigation Center in Paris, then at the National Center for Research and Training on Malaria (CNRFP) in Ouagadougou, Burkina Faso. The participants were randomly assigned to 4 cohorts, receiving the vaccine at various doses, on 3 occasions over a period of 3 months. These women were then monitored for 15 months in order to identify and treat any side effects and study the immune response induced by the vaccination.

The results of this study show that PRIMVAC is well tolerated. In addition, the researchers have shown that vaccine can produce an immune response, with the production of antibodies in 100% of women vaccinated after only two injections. The antibodies produced are capable of both recognizing the parasitic antigen on the surface of the infected red blood cells and inhibiting their adhesive capacity, which is responsible for their accumulation in the placenta.

"We were able to show that the vaccine is well tolerated, at all the tested doses. The side effects observed were mainly pain at the injection site. We also revealed that the quantity of antibodies generated by the vaccine increases after each vaccination and that they persist for several months. It therefore appears that the vaccine has the capacity to trigger a lasting and potentially protective immune response", underlines Gamain.

Studying this immune response on the longer term will be the subject of future clinical trials. The researchers want to continue monitoring the 50 Burkinabe volunteers in order to evaluate whether the immune response induced by the vaccination is maintained until their first pregnancy.
-end-


INSERM (Institut national de la santé et de la recherche médicale)

Related Malaria Articles from Brightsurf:

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 UmeƄ 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.

Read More: Malaria News and Malaria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.