Effectiveness of one-dose MenACWY-D drops over time

(HealthDay)—For adolescents, the effectiveness of the one-dose meningococcal (groups A, C, W, and Y) polysaccharide diphtheria toxoid conjugate vaccine (MenACWY-D) decreases at three to less than eight years post-vaccination, according to a study published online Jan. 18 in Pediatrics.

Amanda C. Cohn, M.D., from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues conducted a case-control evaluation of vaccine effectiveness (VE) and duration of protection of MenACWY-D. They identified cases of culture- or polymerase chain reaction-confirmed serogroup A, C, W, and Y meningococcal disease among adolescents through meningococcal disease surveillance sites. Per case, the authors attempted to enroll four friend and school controls.

Serogroups C, Y 80, and W 13 accounted for 49, 44, and 7 percent of enrolled cases, respectively. Twenty percent of cases and 44 percent of controls received MenACWY-D. The researchers found that at zero to eight years post-vaccination, the overall VE estimate was 69 percent: VE was 79, 69, and 61 percent, respectively, at less than one year, one to less than three years, and three to less than eight years. VE was 77 and 51 percent, respectively, against serogroups C and Y.

"MenACWY-D was effective in the first year after vaccination but effectiveness waned three to less than eight years post-vaccination," the authors write. "The estimates of VE from this evaluation informed the Advisory Committee on Immunization Practices in its decision to add a booster dose of MenACWY."

One author disclosed financial ties to the pharmaceutical industry.