February 10, 2020

Research Roundup: Vaccine candidate for gestational malaria, FDA fast-tracks coronavirus diagnostic, and Zika vaccine induces potent Zika and dengue antibodies

Ansley Kahn
Senior Program Assistant
PATH/Matthew Dakin

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A vaccine candidate for gestational malaria, known as PRIMVAC, has yielded promising results in a small clinical trial evaluating its safety and effectiveness. PRIMVAC was shown to be well-tolerated and to elicit an immune response in 100 percent of the 68 non-pregnant women vaccinated after only two injections and for up to 15 months after the initial vaccination. Malaria is particularly dangerous to pregnant women because the red blood cells infected with the Plasmodium falciparum parasite that causes malaria accumulate in the placenta, promoting anemia and gestational hypertension. Gestational malaria is also linked to a higher risk of spontaneous abortion, premature birth, and intrauterine growth delays leading to low birth weight and a high rate of neonatal mortality. Future clinical trials will focus on studying the immune response elicited by PRIMVAC longer term.

Last Tuesday, the US Food and Drug Administration (FDA) issued an emergency use authorization of a diagnostic test for the novel coronavirus (2019-nCoV) that has emerged in China, sickening more than 20,000 people and killing 427 globally. This exemption will make the test—developed by the Centers for Disease Control and Prevention (CDC)—available to public health labs across the United States and around the world in an effort to contain the disease’s spread. CDC has already shipped the test to a repository where states and international partners can order it. The nonprofit Foundation for Innovative New Diagnostics (FIND)—which works to expand diagnostic capacity in low-resource countries—is now using viral isolates of 2019-nCoV to evaluate the CDC’s diagnostic test and others like it.

Scientists at the Walter Reed Army Institute of Research (WRAIR) have shown for the first time that a single dose of an experimental Zika vaccine, ZPIV, in individuals previously infected by dengue can boost pre-existing immunity and elicit antibody responses against both Zika and dengue. This result was compared to trial volunteers with no prior exposure to dengue who required two vaccinations of ZPIV to reach a similar magnitude of Zika antibody responses. These findings indicate that an effective Zika vaccine could boost dengue virus immunity and generate Zika antibodies that have the potential to be a prevention tool in regions where both diseases are endemic. In three phase 1 human clinical trials the ZPIV vaccine, developed by WRAIR, has shown to be safe and well-tolerated in healthy adults and to induce a robust immune response.