Researchers at the University of Texas Medical Branch at Galveston have developed an oral vaccine against the foodborne pathogen responsible for the most hospitalizations and deaths in the United States.

It will likely take about five years before the Salmonella vaccine is available to the public, said lead researcher Ashok Chopra, professor of microbiology and immunology at the University of Texas Medical Branch at Galveston.

Salmonella is the second leading cause of foodborne illness in the United States, sickening more than a million people every year, according to the Centers for Disease Control and Prevention. Norovirus is the No. 1 cause of foodborne illness in the U.S., with the CDC estimating annual cases at 4.5 million.

However, Salmonella infection is much more serious than norovirus, causing more hospitalizations and deaths — about 19,300 hospitalizations and almost 400 deaths annually — than any other foodborne pathogen in the U.S.

Despite public health efforts at the local, state and federal levels, the CDC reports Salmonella infection rates have remained roughly unchanged in the United States since 1996.

The researchers at the University of Texas previously developed a potential injectable Salmonella vaccine, but oral vaccines are much preferred because they are easier to administer and less invasive than injections, Chopra said.

Salmonella infection can be treated with antibiotics, but some strains of the pathogen are developing antibiotic resistance, increasing the need for a vaccine. Also, the pathogen can be used as a bioweapon, as it was in Oregon in 1984 when a religious cult contaminated restaurant salad bars, sickening more than 750 people.

The research at the University of Texas was supported with money from the federal government’s National Institutes of Health. In addition to Chopra, others involved in the Salmonella vaccine project are Tatiana Erova, Michelle Kirtley, Eric Fitts, Duraisamy Ponnusamy, Jourdan Andersson, Yingzi Cong, Bethany Tiner and Jian Sha as well as Wallace Baze from the University of Texas M.D. Anderson Cancer Center.