Nasal Vaccine Shows Promise as Booster Against Pneumonic Plague

Four years ago, Albany Medical College scientists were awarded a $3 million grant from the National Institutes of Health to develop a vaccine that could protect against plague.

Now, as detailed in a paper in Nature Communications, their work has produced some promising results.

Pneumonic plague is a severe lung infection caused by the bacteria Yersinia pestis. While it is not as common as bubonic plague, it can be more deadly. In the U.S., plague is most common in rural areas of the southwest, particularly New Mexico, Arizona and Colorado.

Led by Professor Wei Sun, PhD, and Research Associate Saugata Majumder, PhD, from the Department of Immunology and Microbial Disease, the researchers first developed and tested an intramuscular OMV (outer membrane vesicle) vaccine with an alum adjuvant against pneumonic plague. (Adjuvants are substances that are added to vaccines to enhance the body’s immune response, but which can potentially cause toxicity to the lungs and central nervous system when administered nasally.)

They found this vaccine to be effective in animal models, but long-term protection against respiratory infection was limited.

With the goal of improving immunity, they then tested a “prime-spike” regimen—that is, the initial intramuscular vaccine followed by intranasal boosting with an unadjuvanted antigen. This was much more effective at augmenting lung immunity against pneumonic plague than the intramuscular vaccine alone.

The researchers note that while additional studies are needed, during an emergent pneumonic plague outbreak, the nasal vaccine could potentially be key to rapidly boosting lung immunity in those previously vaccinated against plague.