Rosenkranz Prize winner hopes to develop malaria vaccine targeting pregnant women

Prasanna Jagannathan-Rosenkranz

Photo credit: 
Beth Duff-Brown

Malaria claims nearly half-a-million lives worldwide each year — and yet we still know so little about the immunology of the disease that has plagued humanity for centuries.

There were 216 million cases in 2016, according to the World Health Organization. Sub-Saharan Africa carries 80 percent of the global burden of the mosquito-borne infectious disease which devastates families, disrupts education, and promotes the vicious cycle of poverty.

It is particularly brutal to pregnant women, who are three times more likely to suffer from a severe form of the disease, leading to lower birthweight among their newborns and higher rates of miscarriage, premature and stillborn deliveries.

“Pregnant women and their unborn children are more susceptible to the adverse consequences of malaria, so we are working to investigate new strategies and even lay the foundation for a vaccine to prevent malaria in pregnancy,” said Prasanna Jagannathan, MD, an assistant professor of medicine who is this year’s recipient of the Rosenkranz Prize.

Jagannathan, an infectious disease physician who is also a member of Stanford’s Child Health Research Institute, said the $100,000 stipend that comes with the prize will allow his lab members to ramp up their research in Uganda. A member of the nonprofit Infectious Disease Research Collaboration in Kampala, his team is particularly interested in how strategies that prevent malaria might actually alter the development of natural immunity to malaria.

“With support from the Rosenkranz Prize, we hope to identify maternal immune characteristics and immunologic targets that are associated with protection of malaria in pregnancy and infancy,” Jagannathan said.

The Dr. George Rosenkranz Prize for Health Care Research in Developing Countries is awarded each year by the Freeman Spogli Institute for International Studies and Stanford Health Policy to a young Stanford researcher who is trying to improve health care in underserved countries. It was established in 2009 by the family or Dr. George Rosenkranz, a chemist who first synthesized cortisone in 1951, and later progesterone, the active ingredient in oral birth control pills.

“My father has held a lifelong commitment to scientific research as a way to improve the lives and well-being of communities around the world,” said Ricardo T. Rosenkranz, MD. “In particular, he has always sought to improve the health of at-risk populations. Dr. Jagannathan’s work offers the very sort of innovative ingenuity that characterized my father’s early research, as well as his vision towards the future.”

Jagannathan and his collaborators at UCSF and in Uganda are currently conducting a randomized control trial of 782 Ugandan women who are receiving intermittent preventive treatment with a fixed dose of dihydroartemisinin-piperaquine(or IPTp-DP), a medication that has dramatically reduced the risk of maternal parasitemia, anemia, and placental malaria. Their preliminary data suggests that among 684 infants born to these women, maternal receipt of IPTp-DP may lead to a reduced incidence of malaria in the first year of life.

“Having the discretionary support of the Rosenkranz Prize will allow us to generate some preliminary ideas from this trial that could lead to larger studies, to push this agenda further along,” Jagannathan said.

That agenda is to create a vaccine that targets pregnant women to prevent malaria both during pregnancy — but also potentially preventing malaria in infants, giving them a better start in life.

“We’re not the first ones to think of this, but we have the opportunity to test these hypotheses in incredibly unique settings, with really well-studied cohorts that have real-world implications in terms of what we find,” Jagannathan said. “I’m hopeful that the data that’s generated over the new few years will allow us to keep moving forward.”

Jagannathan has been traveling to Uganda for a decade to study malaria. He’s seen firsthand the relentless, gnawing impact the disease has on daily life.

“Before I went to Uganda I really didn’t understand the burden that malaria causes in communities — and it’s just incredible,” he said. His first study was on children aged 5 and under who had on average six episodes of malaria a year.

“They just get it over and over again, and the toll on society is enormous,” he said. The clinics are overwhelmed and a parent or sibling must miss work or school to stay home with that child.

Yet, in highly endemic settings, children eventually develop an immunity that protects against the adverse outcomes from malaria. If he and his colleagues can understand how pregnant women and children develop this clinical immunity to malaria, it could lead to better treatments and preventative strategies.

“If we understand the mechanisms that underlie naturally acquired immunity, that would offer some clues as to how we can develop a vaccine that actually allows either that immunity to occur more quickly or prevents us from developing immunity that allows for the parasite to persist without symptoms,” he said.

There is currently a malaria vaccine undergoing testing in Africa. The vaccine, known as RTS,S, was developed by GlaxoSmithKline and the PATH Malaria Vaccine Initiative, with support from the Bill and Melinda Gates Foundation. Decades in the making, four doses of the vaccine are required to reduce malaria infection in humans.

“It’s a remarkable vaccine in that it’s effective in the beginning, but the problem is that the efficacy wanes very rapidly,” Jagannathan said, noting that some studies show that beyond three years, the effectiveness drops to 15-20 percent.

“That’s the big issue and why people are really interested in trying to find new strategies and new approaches for a next-generation malarial vaccine,” he said. “That’s the overarching aspect of what motivates my work.”