Impact on meningococcal disease of different vaccination strategies with 4CMenB and MenACWY-CRM197 in infants and adolescents in Argentina.

BACKGROUND

Invasive meningococcal disease (IMD) is a life-threatening disease, primarily affecting infants and children. Argentina introduced routine meningococcal vaccination in infants and adolescents in 2017, with MenACWY vaccination targeting serogroups A, C, W, and Y (current National Immunization Program [cNIP]). Serogroup B, more prevalent since 2015, became predominant in children. The dynamic trends of IMD epidemiology and availability of a four-component meningococcal B vaccine (4CMenB) call for a reassessment of the best schedule to optimize IMD prevention. The objective was to model the public health impact of routine 4CMenB and/or MenACWY in infants and adolescents, using different vaccination strategies compared with the cNIP in Argentina.

METHODS

A published dynamic transmission model adapted for Argentina evaluated six vaccination strategies versus the cNIP: infant 4CMenB alone (1), infant 4CMenB with adolescent MenACWY (2), adolescent MenACWY alone (3), infant 4CMenB & MenACWY (4), infant MenACWY alone (5), and infant 4CMenB & MenACWY with adolescent MenACWY (6).

RESULTS

Strategies including adolescent MenACWY with infant 4CMenB (or 4CMenB plus MenACWY) vaccination had the largest impact on increasing IMD prevention i.e., up to 23 % higher than the cNIP after 25 years. Strategies including 4CMenB (1, 2, 4, 6) had the largest reduction of serogroup B IMD (impact is seen among children 0-4 years old) i.e., a 39 % decrease within the first five years of introducing 4CMenB. Strategies including adolescent MenACWY (cNIP, 2, 3 and 6) had the largest reduction of serogroup ACWY IMD, with near elimination after 30 years (impact seen in all ages, due to herd protection).

CONCLUSIONS

Adding routine infant 4CMenB (either to the complete cNIP or instead of infant MenACWY) could further reduce IMD cases, sequelae, and deaths in Argentina. In addition, maintaining the adolescent MenACWY program, with its herd immunity benefits, could achieve near elimination of serogroup ACWY IMD over 30 years.