Breakthrough mRNA Vaccine Achieves 100% Effectiveness Against Plague

In a groundbreaking development, scientists from Tel Aviv University and the Israel Institute for Biological Research (IIBR) have successfully created the first mRNA-based vaccine targeting the Yersinia pestis bacterium, which causes pneumonic plague. This innovative vaccine, which demonstrated a remarkable 100% effectiveness in animal trials, signifies a major advancement in combating antibiotic-resistant infections, echoing the success of mRNA technology in COVID-19 vaccines.

The research, published in the prestigious journal *Advanced Science* on July 14, 2025, highlights the collaborative efforts of Prof. Dan Peer, Dr. Edo Kon, Dr. Inbal Hazan-HaLevy, and PhD student Shani Benarroch from Tel Aviv University and IIBR. Prof. Peer emphasized the urgency of developing effective vaccines against Yersinia pestis, stating, "Despite extensive global efforts over several decades, no vaccines have been approved in Western countries for this notorious bacterial pathogen. This gap in protection is particularly concerning given that Y. pestis is classified as a Tier 1 biothreat agent due to its ability to cause plague—a severe and often fatal disease."

Yersinia pestis, the bacterium responsible for the historic Black Death, is primarily transmitted to humans through bites from infected fleas. The pneumonic form of the plague is particularly dangerous, as it can spread from person to person through respiratory droplets. The resurgence of interest in this pathogen is prompted by its potential to cause outbreaks and the growing issue of antibiotic resistance, which complicates treatment options.

The new mRNA vaccine utilizes lipid nanoparticles to deliver the genetic material that instructs cells to produce a harmless piece of the bacterium, prompting an immune response. This method mirrors the approach used in the development of COVID-19 vaccines, which have proven effective against the virus responsible for the global pandemic.

Dr. Michal Shafir, a microbiologist at the University of California, Berkeley, commented on the significance of this development, stating, "The advancement of mRNA technology could revolutionize our approach to infectious diseases, particularly those that have been neglected. The rapid adaptability of this platform allows for quicker responses to emerging threats."

Globally, the public health community has expressed cautious optimism regarding the implications of this research. According to the World Health Organization (WHO), outbreaks of plague still occur, with occasional cases reported in countries such as the United States, Madagascar, and the Democratic Republic of Congo. The potential for a resurgence of pneumonic plague, particularly in areas where antibiotic resistance is increasing, underscores the importance of developing new vaccines.

The research team is now focused on progressing to human clinical trials, which will be crucial in determining the vaccine's safety and efficacy in broader populations. Prof. Peer noted, "While we are optimistic about these results, extensive human trials will be necessary to confirm the vaccine's effectiveness against Yersinia pestis in humans."

The implications of this research extend beyond just the fight against plague. Experts believe that mRNA vaccine technology could serve as a blueprint for developing vaccines against a variety of bacterial and viral pathogens, marking a significant leap in the field of immunology.

Looking ahead, public health officials are encouraged by the prospects of new tools in the fight against infectious diseases. The success of this mRNA vaccine could not only provide a much-needed defense against plague but also pave the way for innovative approaches to other public health challenges. As the world continues to grapple with antibiotic resistance and emerging infectious diseases, the development of effective vaccines remains a top priority for global health security.