Yadira Pastor, a biochemist and doctor from the University of Navarra, has developed a vaccine in her doctoral thesis to help curb Shigellosis, a diarrheal disease that causes more than 200,000 deaths a year, according to data from the World Health Organization. This same organization indicates that this disease, which is transmitted by contaminated food and water, is one of the main causes of infant mortality in developing countries. 

The novelty of this research lies in the study of a subunit vaccine, based on the use of outer membrane vesicles of the bacterium Shigella. The young researcher from Navarra has laid the foundations in the development of this vaccine trying to make it "safe, effective, easy to obtain and with the potential for large-scale production". In addition, Pastor has taken into account different routes of administration of the vaccine that avoid the use of needles in order to avoid pain and discomfort in the patient, to favor self-administration and mass vaccination, as well as to reduce the use of biological waste generated after its use. "The easily accessible routes of administration are painless and are capable of generating a good immunological response after vaccination," says Pastor.

Thus, her research proposal is based on the use of immunostimulant gels in the case of nasal administration, or micro-patches for the intradermal route. "Both routes have shown very promising results in mice that, after being vaccinated by both routes, were protected against an experimental infection with Shigella, the bacterium that causes bacterial dysentery," adds Dr. Pastor.  

This research - in the preclinical phase - needs further studies to confirm its efficacy before it can be transferred to humans. Yadira Pastor has laid the foundations for the development of this vaccine by carrying out trials in cells and rodents. "Certain parameters that confirm the efficacy of this vaccine, such as long-term immunity (immunological memory) or cross-protection against other species that could broaden its range of action, still need to be determined".  

At the moment there is no effective vaccine to combat Shigellosis, a disease endemic in developing countries in areas such as Africa, South America and Asia, although it is increasingly present in industrialized countries.