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December 8, 2011

Bloomberg School to Join Evaluation of New Malaria Vaccine

Transmission-blocking Approach Focuses on Mosquito

The Johns Hopkins Bloomberg School of Public Health Center for Immunization Research (CIR), the PATH Malaria Vaccine Initiative (MVI) and the National Institute of Allergy and Infectious Diseases (NIAID) announced a new collaboration to evaluate a potential malaria vaccine designed to prevent transmission of the disease from mosquitoes to humans.

CIR, MVI and NIAID are currently working together to conduct a Phase 1 clinical trial in healthy adults to assess the safety and immunogenicity of the protein Pfs25. Pfs25 is a transmission-blocking vaccine (TBV) that aims to block the transmission of malaria from mosquitoes to humans by preventing the malaria parasite from developing in the mosquito. While such vaccines do not directly protect an immunized individual from developing clinical malaria, by preventing the spread of infection by the mosquito, they can reduce the chances that others in the community contract the disease.

"The Pfs25 vaccine and other transmission-blocking vaccines are unique in their approach in that they target a key stage in the malaria parasite's lifecycle rather than attempting to build immunity to malaria in humans," said Kawsar Talaat, MD, clinical principal investigator and assistant scientist at the Johns Hopkins Bloomberg School of Public Health. "We'll need many tools to bring malaria under control and an effective transmission-blocking vaccine could go a long way toward achieving that goal."

Malaria kills nearly 800,000 people every year, most of them children under the age of 5. Defending against the disease has been challenging because both the parasite and its mosquito host are highly adaptive and have survived for millions of years. A TBV would work synergistically with other interventions such as drugs and insecticides since blocking transmission of the parasite would reduce the pressure on these measures, thereby slowing the development of resistance and thus extending their effectiveness.

"This is the first clinical trial using a transmission-blocking approach supported by MVI," said Ashley Birkett, director of research and development at MVI. “It’s the first step in what is typically a long process of evaluation. Nonetheless, we are excited by the potential of TBVs to significantly limit the spread of malaria infection. Eradication of malaria may be decades away, but we believe a successful TBV—used alongside safe and effective drugs, insecticides, bednets and possibly a malaria vaccine that protects the individual against infection—is essential to achieving that goal.”

About the PATH Malaria Vaccine Initiative (MVI): MVI is a global program established at PATH through an initial grant from the Bill & Melinda Gates Foundation. MVI’s mission is to accelerate the development of malaria vaccines and ensure their availability and accessibility in the developing world. MVI’s vision is a world free from malaria. For more information, please visit

About PATH: PATH is an international nonprofit organization that creates sustainable, culturally relevant solutions, enabling communities worldwide to break longstanding cycles of poor health. By collaborating with diverse public and private sector partners, PATH helps provide appropriate health technologies and vital strategies that change the way people think and act. PATH’s work improves global health and well-being. For more information, please visit

About the Johns Hopkins Bloomberg School of Public Health: As a leading international authority on public health, the Johns Hopkins Bloomberg School of Public Health is dedicated to protecting health and saving lives. Every day, the School works to keep millions safe from illness and injury by pioneering new research, deploying its knowledge and expertise in the field, and educating tomorrow's scientists and practitioners in the global defense of human life. For more information, visit

About the Johns Hopkins Center for Immunization Research (CIR): CIR is a leader in vaccine evaluation and Good Clinical Practice (GCP) training. Established in 1985 by Dr. Mary Lou Clements-Mann, CIR is one of the nation’s leading vaccine research centers. CIR investigators primarily conduct Phase I and II clinical trials of new vaccine candidates in the United States and in less-developed countries. For more information, please visit

About the National Institute of Allergy and Infectious Diseases (NIAID): NIAID conducts and supports research—at NIH, throughout the United States, and worldwide—to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website at

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 institutes and centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit

Media contact: Tim Parsons, director of Public Affairs, at 410-955-7619 or