Skip Navigation

Pneumonia Vaccine Developed by OU College of Medicine Researcher Being Tested in Clinical Trial


Pneumonia Vaccine Developed by OU College of Medicine Researcher Being Tested in Clinical Trial

October 12, 2023

OKLAHOMA CITY — A new vaccine candidate to provide broad protection against pneumonia, developed by a researcher at the University of Oklahoma College of Medicine, is being given to humans for the first time in a Phase I clinical trial.

The research that created the vaccine candidate comes from the laboratory of Rodney Tweten, Ph.D., a George Lynn Cross Professor of Research in the Department of Microbiology and Immunology in the OU College of Medicine. The OU Office of Technology Commercialization secured patent protection for Tweten’s technology and the university subsequently licensed it to the vaccine development company Matrivax. The company is currently testing the safety, tolerability and immune response of the vaccine at clinical sites in the United States.

For more than 30 years, Tweten’s research has focused on a specific class of toxins produced by many pathogenic bacteria, including Streptococcus pneumoniaeStreptococcus pneumoniae causes pneumonia, which kills more than 1 million people each year worldwide, often in developing countries and particularly among the elderly, in people whose immune systems are compromised, and children under age 5. In preclinical studies, Tweten’s vaccine appeared to protect against nearly all Streptococcus pneumoniae variants.

“This clinical trial is a result of my research team’s deep understanding of how these toxins work,” Tweten said. “It is exciting because, theoretically, this vaccine should protect against most of the 90 or so different variants (serotypes) of streptococcal pneumonia that we know about.”

Rodney Tweten, Ph.D.

The promise of Tweten’s vaccine is that it takes a different approach than the handful of pneumonia vaccines now on the market. Currently approved vaccines are carbohydrate-based, meaning they prompt the immune system to recognize part of the sugar coating found on Streptococcus pneumoniae, thereby protecting against infection. However, these vaccines protect against 23 variants of the bacteria at most, which leaves open the possibility of infection from 60-plus other variants. In addition, children under age 5 do not mount a strong immune response to the sugar coating of bacteria.

Tweten’s vaccine, in contrast, uses a genetically modified, inactive version of a Streptococcus pneumoniae toxin called pneumolysin, against which the immune system makes antibodies. The antibodies essentially coat the toxin and prevent it from causing disease.

“Because we have changed the structure of pneumolysin very little, the body’s immune memory will respond after vaccination and start making antibodies,” Tweten said. “Unlike the current vaccines, which prompt the immune system to respond to specific variants, we believe our vaccine will protect against the majority of Streptococcus pneumoniae serotypes.”

In addition, Tweten’s vaccine should cost less to manufacture than other pneumonia vaccines, which would make it more affordable for developing countries.

“This Phase I study is an exciting milestone for Matrivax, and a major step forward in the development of a vaccine that has potential to be a technological breakthrough in vaccination options against pneumococcal disease,” said Enda Moran, chief executive officer of Matrivax. “While there are effective vaccines currently available, they are very expensive to the end user, and they don’t protect against all the bacterial serotypes that can cause disease. Our low-cost manufacturing platform and the prospect of a single-component, broad-coverage vaccine can translate directly into a much-needed low-cost vaccine for pneumococcal disease.”

Darrin Akins, Ph.D., vice president of research at OU Health Sciences, said the clinical trial for Tweten’s vaccine candidate underscores the importance of basic science research in making discoveries that may ultimately save lives.

“Over the years, Dr. Tweten has developed substantial knowledge about these toxins. That level of dedication is the critical first step toward translating the science into a potential vaccine,” Akins said. “This pneumonia vaccine candidate represents a milestone for Dr. Tweten’s laboratory, for the OU College of Medicine, and for the OU Health Sciences.”

OU College of Medicine at the University of Oklahoma Health Sciences

Founded in 1910, the OU College of Medicine at the University of Oklahoma Health Sciences trains the next generation of healthcare professionals. The University of Oklahoma Health Sciences is the academic partner of OU Health, the state’s only comprehensive academic health system of hospitals, clinics and centers of excellence. With campuses in Oklahoma City and Tulsa, the College of Medicine offers the state’s only Doctor of Medicine degree program and a nationally competitive Physician Assistant program. For more information, visit

About the University of Oklahoma

Founded in 1890, the University of Oklahoma is a public research university located in Norman, Oklahoma. As the state’s flagship university, OU serves the educational, cultural, economic and health care needs of the state, region and nation. OU was named the state’s highest-ranking university in U.S. News & World Report’s most recent Best Colleges list. For more information about the university, visit