Effective vaccine against placental malaria: Where we are and what does the future hold?
A new review article on Placental Malaria has been published in Frontiers in Immunology. The publication, entitled Progress and Insights Toward an Effective Placental Malaria Vaccine, results from long standing collaboration of over 15 years between European Vaccine Initiative and researchers at Inserm and University of Copenhagen. The authors, including Dr. Nicola Viebig, EVI’s Chief Scientific Officer, review recent pre-clinical and phase I clinical trial data, namely generated in EU-funded and EVI-led projects PRIMALVAC and PAMCPH/PlacMalVac, as well as its implications for the future of the placental malaria vaccine development. During their first pregnancies, pregnant women are particularly susceptible to placental malaria and the associated serious clinical outcomes, such as maternal anaemia, hypertension, stillbirth and low birth weight due to premature delivery, and foetal growth retardation. There are no licensed vaccines for placental malaria and current strategies to prevent the disease rely on control of malaria parasite-carrying mosquitoes and intermittent preventive treatment with anti-malarials during pregnancy (IPTp).
In the researchers’ journey towards finding the best vaccine candidate, they found that protection to placental malaria was associated with the presence of antibodies against VAR2CSA, a protein expressed on the surface of malaria-infected red blood cells. Two phase I randomized, double-blind, placebo-controlled clinical trials were carried out, testing two distinct VAR2CSA-derived vaccine candidates (PRIMVAC and PAMVAC). All formulations tested were safe and well tolerated. Remarkably, the vaccine-induced antibody response seems to mimic the naturally acquired immune response observed following first infection in pregnant women.
For the future, researchers hope to further study the effects of alternative immunization schedules, dosage, and strategies to broaden protection against other parasite variants, striving to develop safe, effective and affordable vaccines and fully protect women from placental malaria.
About PRIMALVAC, PlacMalVac and PAMCPH
The PAMCPH/ PlacMalVac and PRIMALVAC projects, each focussing on a domain of the VAR2CSA leading antigen. Both projects proposed to develop a VAR2CSA-based vaccine against placental malaria using complementary approaches from pre-clinical testing to production stage all the way to clinical testing. Results from the Phase I trial demonstrated that the vaccines were safe, well-tolerated and immunogenic in healthy volunteers.
These projects were funded by the EU programme FP7-Health-2012-Innovation (ID: 304815), the Danish National Advanced Technology Foundation, , the German Federal Ministry of Education and Research through Kreditanstalt für Wiederaufbau (ref: 202060457), Inserm and Institut National de Transfusion Sanguine, France and the Irish Aid, Department of Foreign Affairs and Trade, Ireland. More info>>