MenACWY Vaccination Prevents Invasive Meningococcal Disease

Source: Shin T, Wells CR, Shoukat A, et al. Quadrivalent conjugate vaccine and invasive meningococcal disease in US adolescents and young adults. JAMA Netw Open. 2024;7(11):e2443551; doi: 10.1001/jamanetworkopen.2024.43551.Investigators from multiple institutions conducted an analysis to estimate whether quadrivalent meningococcal conjugate vaccine (MenACWY) was associated with reduction in the invasive meningococcal disease (IMD) burden in the US adolescent population, and whether MenACWY prevented deaths from IMD. A single dose of MenACWY was recommended for 11–12 year olds in the US in 2005, and a booster dose at 16 years of age was recommended in 2010. For the study, the yearly incidence of IMD caused by serogroups C, W, and Y in age groups ranging from <1 to 65 years of age from 2001 to 2021 was determined using CDC data. There was only 1 case of IMD caused by serogroup A, thus this serogroup was omitted from the analysis. Cases of IMD were stratified by vaccination status between 2004–2021, using direct data or extrapolation from surveillance information. In addition, MenACWY uptake trends among adolescents 11–15 and 16–18 years old were estimated using statistical modeling of available data. Finally, case fatality rates from IMD and vaccine failure rates were estimated. These variables were used in a Bayesian hierarchical Poisson regression model to assess trends in IMD in US adolescents 11–23 years old during the study period. The model was repeated with the counterfactual scenario of no adolescent MenACWY vaccine. The difference in the estimated IMD burden, with and without a vaccination program, was used to estimate the number of cases of IMD averted and, using case fatality estimates, determine the number of deaths from IMD prevented.Using the data collected for the statistical models, it was estimated that MenACWY vaccination prevented 172 cases of IMD between 2005 and 2021 in US adolescents aged 11–15 years (95% credible interval [CrI], 85, 345) and 328 cases of IMD among those 16–23 years old (95% CrI, 164, 646). Without the MenACWY vaccination program, the incidence of IMD among adolescents would have been at least 59% higher than what was observed with vaccination. Case fatality rates from IMD associated with C, W, and Y serogroups were calculated to be 9.1% among unvaccinated adolescents who were 11–15 years old and 11.6% for those 16–23 years old. Using these values, it was estimated that MenACWY vaccination prevented 16 deaths in adolescents 11–15 years of age (95% CrI, 8, 31) and 38 deaths in those 16–23 years old (95% CrI, 19, 75).The authors conclude that MenACWY vaccination was associated with a reduced IMD burden in US adolescents.Dr Brady has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.Investigators from the CDC previously reported their results of a study conducted from 2000–2017 that assessed the impact of MenACWY vaccination on the incidence of meningococcal disease among US adolescents 11 to 22 years old. (See AAP Grand Rounds. 2020;44[6]:63.)1 They estimated that 222 cases of meningococcal disease associated with serogroups C, W, and Y were averted among adolescents through vaccination during 2000–2017. As expected, the estimated 500 averted cases in the current study were higher because the study period included 2018–2021, and routine MenACWY vaccination of adolescents was implemented in the US in 2005.2Both studies suggest that the MenACWY vaccination program has a critical role in reducing the incidence of IMD. Despite this benefit, uptake of the booster dose among those 16–23 years old remained <60% in 2021. Herrera-Restrepo et al conducted a literature review to understand the determinants of meningococcal vaccination coverage among older adolescents.3 They identified 4 determinants associated with improved coverage: (1) well child, preventive, or vaccination-only appointments; (2) provider-initiated, provider-driven vaccine recommendations; (3) provider education about meningococcal disease and vaccine recommendations; and (4) state-level school-entry immunization requirements. Currently, 25 states require 1 MenACWY dose before age 16 years with a booster dose at ≥16 years, 10 states require only 1 dose before 16 years, and 15 states have no requirement.4 Cheng et al previously reported that having >1 annual health visit and presence of a booster-dose vaccine mandate were factors associated with completion of the recommended MenACWY 2-dose schedule.5 A 2024 CDC survey found that only 76.6% of parents supported vaccination requirements for school and daycare attendance.6 With parental support for vaccines declining, attendance at well child visits at which vaccination recommendations are discussed will be increasingly important.MenACWY vaccination reduces IMD and deaths from IMD among adolescents. Efforts to improve vaccination rates are needed.It is important to note what was not assessed in the current study: meningococcal B disease and its prevention. Serogroup B accounts for one-third of US cases and is the most common cause of disease in adolescents. Monovalent B and polyvalent vaccines including B are available for permissive use in 16–23-year-olds and routine use in high-risk individuals (eg, immunocompromised).7