Chlamydia Vaccine: A Costly Solution to STD-Related Morbidity & Mortality

Developing and distributing a vaccine for Chlamydia trachomatis could be an expensive proposition, but it may be worth it.

On March 5, researchers who presented their findings at the 2017 Annual Meeting of the American Academy of Allergy, Asthma & Immunology (AAAAI) in Atlanta, Georgia, suggested that the asymptomatic nature of the sexually transmitted disease (STD) could prevent a large number of women from acquiring the infection at ages as young as 11 and from suffering from many related health complications throughout their lives.

“The majority of genital chlamydia infections in women are asymptomatic,” lead author on the study, Jared Ditowsky, BA, an MD candidate, and a member of the Department of Pediatrics in the State University of New York Downstate Medical Center’s Division of Infectious Diseases, observed. He added, “The largest burden from the infection is in women where untreated infections result in pelvic inflammatory disease.” He also noted that infants born to women with untreated chlamydia may acquire the chlamydia infection during the birth process , which could lead to respiratory problems, and current screening programs for the infection are not necessarily effective for decreasing prevalence.

“Although there is not presently a vaccine for chlamydia infections, we wanted to create a model that would estimate costs and health-related [factors] associated with such a vaccine,” Ditowsky explained. He noted that the Centers for Disease Control and Prevention (CDC) estimated that in 2013 there were more than 1.4 million cases of chlamydia in the United States; treatment-related expenses for these infections can cost more than $500 million over the course of the patient’s life. “We wanted to see if vaccine development might be necessary for controlling infection,” he explained.

Ditowsky and his team created a predictive model to be used in a study group consisting of women above the age of 9 living within the United States. They selected a low age cut-off for the study in order to remain in-line with other STD-preventative vaccines, such as the HPV vaccine, which may be administered as early as the age of nine. “Our research suggests that acquisition of C. trachomatis in women occurs as early as 11 years of age,” he noted, adding that when the CDC reported on the potential cost-effectiveness of a chlamydia vaccine, it assumed that vaccination would begin at 14 years of age.

The group studied a population of 2,158,117 women, and, using their model, predicted the costs and morbidity associated with chlamydia infection over a 17-year period, including costs to the healthcare system if the infection went undiagnosed and a woman eventually delivered an infant preterm or with associated respiratory problems, or both. “We based our assumption that 39.7% of the women in our analysis would be vaccinated on the current vaccination rates for the HPV vaccine,” Ditowsky explained. He also noted that using these numbers, although a chlamydia vaccine would not be cost-saving, it would dramatically reduce chlamydia infection rates (by 34,088 according to the model) and avert 5,976 cases of pelvic inflammatory disease (PID).

“The vaccine becomes cost-saving when chlamydia prevalence is raised by 50%,” Ditowsky noted. At present, the CDC estimates that about 5% of sexually active young women already have chlamydia. Chlamydia infection rates in the United States are on an upward trend, rising by nearly 6% between 2014 and 2015, according to the CDC’s 2015 Sexually Transmitted Diseases Surveillance publication. Furthermore, at the moment, while the infection is easily treatable with antibiotics, some chlamydia strains are beginning to show antibiotic-resistance, which could dramatically change the equation for this research group’s model.

Ditowsky concluded that his group believes a chlamydia vaccine would have “the greatest potential market in developed countries,” and added that such a vaccination would “avert significant morbidity, but without saving cost to the healthcare system.”