Emerging Infectious Diseases (Feb 2024)
Impact of Meningococcal ACWY Vaccination Program during 2017–18 Epidemic, Western Australia, Australia
Abstract
The rising incidence of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup W in Western Australia, Australia, presents challenges for prevention. We assessed the effects of a quadrivalent meningococcal vaccination program using 2012–2020 IMD notification data. Notification rates peaked at 1.8/100,000 population in 2017; rates among Aboriginal and Torres Strait Islander populations were 7 times higher than for other populations. Serogroup W disease exhibited atypical manifestations and increased severity. Of 216 cases, 20 IMD-related deaths occurred; most (19/20) were in unvaccinated persons. After the 2017–2018 targeted vaccination program, notification rates decreased from 1.6/100,000 population in 2018 to 0.9/100,000 population in 2019 and continued to decline in 2020. Vaccine effectiveness (in the 1–4 years age group) using the screening method was 93.6% (95% CI 50.1%–99.2%) in 2018 and 92.5% (95% CI 28.2%–99.2%) in 2019. Strategic planning and prompt implementation of targeted vaccination programs effectively reduce IMD.
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