Tulane University researchers are developing a vaccine formulation that may provide longer lasting immunity in fewer doses against pertussis, more commonly known as “whooping cough.”

Microbiologist Lisa Morici, PhD, and immunologist James McLachlan, PhD, are leading the project to use outer membrane vesicles (OMVs), which are nanoparticles shed by bacteria as they grow, to stimulate a more potent immune response than current vaccines against the disease.

OMVs are an emerging technology as a new class of adjuvants or immune system triggers in next-generation vaccines. Our bodies recognize OMVs secreted by live bacteria during natural infection. When used in vaccines, they can fool the body into mounting a similar immune response.

The National Institutes of Health has awarded Tulane University School of Medicine a contract for up to $8.5 million over five years to support this effort.

The researchers will add OMVs to DTaP, an existing vaccine against three deadly diseases caused by bacteria: diphtheria, tetanus and pertussis. They’ll evaluate the OMV-based vaccine’s safety and effectiveness in animal models to pave the way for potential clinical studies.

Worldwide, there are an estimated 24.1 million cases of pertussis and about 160,700 deaths per year, according to the Centers for Disease Control. Despite widespread vaccination, pertussis cases have spiked in the U.S. in the last decade and a half with almost 18,000 reported in 2016.

Part of the increase is blamed on limitations of the current vaccine, which doesn’t provide lasting immunity and may not prevent person-to-person transmission. Children must get a series of doses before age 1 and need another at the end of adolescence. Continued compliance is also an issue as adults need a booster shot to retain immunity.

The researchers will test different versions of the vaccine delivered as injections under the skin or into muscle as well as nasal and oral formulations.