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Sunday, May 26, 2024

UC Davis launches E. coli vaccine trial

The clinical trial aims to reduce the occurrence of Invasive E. coli disease in patients who are 60 and older


By KATIE HELLMAN — science@theaggie.org 


According to a recent study by UC Davis, a vaccine trial has been launched to prevent Invasive Escherichia coli disease (IED), caused by a bacteria commonly known as E. coli. The efficacy of the new ExPEC9V vaccine will be assessed in patients 60 years and older, which is the age group that is associated the most strongly with complications from urinary tract infections (UTIs). UTIs are almost always a result of E. coli bacteria infections.

“The E. coli bacteria may spread from the urinary tract to the bloodstream and other locations in the body and cause an infection called an invasive [also known as systemic] infection,” the study reads. “Although IED affects all ages, adults aged 60 years and older have an increased risk of developing IED. The risk of developing an IED is further increased in elderly, who had a UTI in the past.”

The clinical trial is double-blind and placebo-controlled, which means that both the researchers and the participants won’t know who is receiving the actual vaccine and who is receiving the placebo. This prevents bias when the researchers are collecting data from the clinical trial.

According to a 2021 study, the University of Texas at Dallas developed a vaccine specifically designed to prevent UTIs that showed promising results in mice. Nicole De Nisco, an assistant professor of biological sciences at UT Dallas, discussed the necessity of this medical advancement in an article on the university’s website.

“Vaccination as a therapeutic route for recurrent UTIs is being explored because antibiotics aren’t working anymore,” De Nisco said. “Patients are losing their bladders to save their lives because the bacteria cannot be killed by antibiotics or because of an extreme allergy to antibiotics, which is more common in the older population than people may realize.”

Almost 20,000 participants aged 60 or older who have had a UTI in the past two years will take part in the UC Davis study, and they will be monitored by researchers over the course of three years. The main goals of the clinical trial include testing the vaccine’s safety and efficacy in addition to its potential side effects and how long its immunity will last.

Stuart Cohen, chief of infectious diseases at UC Davis and principal investigator of the study, commented on the effects of E. coli bacteria and the implications of the vaccine.

“This vaccine targets nine strains of E. coli,” Cohen said. “E. coli, as many people know, is part of the normal bacteria in the intestines, but it can also cause sepsis and it is the most common cause of urinary tract infections.”

Sepsis is a severe condition of blood poisoning that arises from an uncontrolled infection. In this case, if an E. coli infection spreads throughout the bloodstream and is left untreated, it can lead to symptoms like fatigue, vomiting, nausea and a low fever. The ExPEC9V vaccine, which will ideally prevent these issues from occurring, belongs to a group of conjugate vaccines characterized by their use of bacteria to generate an immune response. This specific vaccine will trigger the body’s immune system to produce antibodies, which will then neutralize any potential E. coli strains. 

“Once the whole immune cascade of sepsis starts, it’s hard to stop,” Cohen said. “The mortality rate is still high even with aggressive antibiotics, and even the people who survive may have organ damage. The idea [of the vaccine] is to get this immune response going so people either don’t get an infection or they end up getting a modified infection.”

Written by: Katie Hellman — science@theaggie.org