Dual Impact of 4CMenB: Strong Meningococcal B Protection and Waning Gonorrhea Immunity After Five Years

Five years into South Australia’s rollout of the 4CMenB vaccine, new real-world data suggest sustained and high vaccine effectiveness (VE) against invasive meningococcal B (MenB) disease in infants, children, and adolescents—and reveal time-limited protection against gonorrhea in adolescents.

Published in Clinical Infectious Diseases, this population-based cohort and case-control study evaluated outcomes across more than 334,000 administered doses since the program’s launch in late 2018 for children and early 2019 for adolescents.

The 4CMenB program sharply reduced MenB incidence across all vaccinated age groups:

• Infants (<1 year) experienced a 72.7 percent relative reduction in MenB incidence (adjusted incidence rate ratio [aIRR] 0.273)
• Adolescents (15–18 years) saw a 76.2 percent reduction (aIRR 0.238), aligning closely with international VE estimates ranging from 55–100 percent

Effectiveness remained high within five years post-vaccination:

• 98.5 percent for children receiving a three-dose schedule
• 92.3 percent for adolescents with two-dose schedules

The same vaccine, originally designed for MenB, also showed cross-protection against gonorrhea, attributable to the genetic similarities between Neisseria meningitidis and Neisseria gonorrhoeae. Among adolescents:

• VE against gonorrhea was 39.1 percent for those receiving two doses
• Protection dropped to –6.3 percent beyond five years but remained at 41.8 percent within the first five years
• A Cox regression model demonstrated a 27 percent reduced hazard of subsequent gonococcal infection among fully vaccinated individuals

These findings align with international studies suggesting outer membrane vesicle-based MenB vaccines may reduce gonorrhea risk, although more targeted immunogenicity studies are needed.

Uptake of the vaccine has been strong:

• Over 334,000 doses have been administered to children.
• Three-dose coverage reached 81.4 percent in eligible children.
• Adolescent vaccine coverage peaked at 68.4 percent among the 2005 birth cohort.

Given rising antibiotic resistance in gonorrhea and the lack of a dedicated gonococcal vaccine, 4CMenB presents a rare dual-prevention strategy. These findings support recent UK guidance recommending 4CMenB for individuals at elevated risk of gonococcal infection.

Limitations and Research Gaps

Despite the robust dataset and near-complete vaccine registry (AIR), the study faced limitations:

• Small case numbers in older cohorts limit precise VE estimates beyond five years.
• Lack of genomic surveillance data leaves gaps in understanding vaccine failure cases.
• Asymptomatic STIs and underdiagnosed gonorrhea may affect VE estimates due to misclassification.

Further investigation is needed into optimal timing for adolescent or early adult boosters—especially for high-incidence or high-risk populations.

For health systems navigating the rising tide of gonococcal resistance, these findings position 4CMenB not just as a meningitis prevention tool, but as a potential strategic asset in broader infectious disease control.

Reference

Wang B, Giles L, Andraweera P, et al. Long-term protection against invasive meningococcal B disease and gonococcal infection 5 years after implementation of funded childhood and adolescent 4CMenB vaccination program in South Australia: An observational cohort and case-control study. Clin Infect Dis. Published online July 10, 2025. doi:10.1093/cid/ciaf372