Vaccine Impact and Effectiveness of Meningococcal Serogroup ACWY Conjugate Vaccine Implementation in the Netherlands: A Nationwide Surveillance Study

Abstract

Background In response to the recent serogroup W invasive meningococcal disease (IMD-W) epidemic in the Netherlands, meningococcal serogroup C (MenC) conjugate vaccination for 14-month-olds was replaced with a MenACWY conjugate vaccination, and a mass campaign targeting 14-18 year-olds was executed. We investigated the impact of MenACWY vaccination implementation in 2018-2020 on incidence rates and estimated vaccine effectiveness (VE). Methods We extracted all IMD cases diagnosed between July 2014 and December 2020 from the national surveillance system. We calculated age group-specific incidence rate ratios by comparing incidence rates before (July 2017-March 2018) and after (July 2019-March 2020) MenACWY vaccination implementation. We estimated VE in vaccine-eligible cases using the screening method. Results Overall, IMD-W incidence rate lowered by 61% (95%CI 40-74). It declined by 82% (95%CI 18-96) in vaccine-eligible age group (15-36 month-olds and 14-18 year-olds) and by 57% (95%CI 34-72) in vaccine non-eligible age groups. VE was 92% (95%CI -20-99.5) against IMD-W vaccine-eligible toddlers. No IMD-W cases were reported in vaccine-eligible teenagers after the campaign. Conclusions The MenACWY vaccination programme was effective in preventing IMD-W in the target population. The IMD-W incidence reduction in vaccine non-eligible age groups may be caused by indirect effects of the vaccination programme. However, disentangling natural fluctuation from vaccine-effect was not possible. Our findings encourage the use of toddler- and teenager MenACWY vaccination in national immunization programmes especially when implemented together with a teenager mass campaign during an epidemic.

Meningococcal vaccination in adolescents and adults induces bactericidal activity against hyperinvasive complement-resistant meningococcal isolates

“…Since vaccination targets the polysaccharide capsule, which is largely independent of the clonal complexassociated genes, we did not expect a link between virulence and ccs when vaccine-induced antibodies were present. Epidemiological data previously suggested vaccine effectiveness against invasive isolates (30), of which we now provide mechanistic proof. While some ccs are implicated in IMD, others are rarely invasive and there is large heterogeneity between isolates belonging to the same cc.…”

Pathogen- and Type-Specific Changes in Invasive Bacterial Disease Epidemiology during the First Year of the COVID-19 Pandemic in The Netherlands

“…For the results presented here, it is important to note that the MenACWY vaccine has been implemented in the Netherlands in 2018 [ 9 ]. Consequently, the decrease in IMD cases caused by serotypes W and Y are partially influenced by the protective effect from MenACWY vaccination [ 10 ]. The decrease in MenB cases by 62% therefore most accurately reflects the impact of COVID-19 on IMD, since IMD-B disease is not affected by a recent introduction of a vaccine.…”

“…MenC was replaced by MenACYW in 2018 [ 9 ]. In addition, a catch-up campaign among 14–18-year olds with MenACWY was organized and the vaccine has been routinely provided to 14-year olds through the NIP since 2020 [ 10 ]. For S. pneumoniae , a 7-valent vaccine (PCV7) was implemented in 2006 and replaced by the 10-valent PCV10 in 2011 [ 11 ].…”

Pathogen- and type-specific changes in invasive bacterial disease epidemiology during the first year of the COVID-19 pandemic in the Netherlands

“…For the results presented here, it is important to note that the MenACWY vaccine has been implemented in the Netherlands in 2018 5 . Consequently, the decrease in IMD cases caused by serotypes W and Y are partially influenced by the protective effect from MenACWY vaccination 6 . The decrease in MenB cases by 62% therefore most accurately reflects the impact of COVID-19 on IMD, since IMD-B disease is not affected by a recent introduction of a vaccine.…”

“…MenC was replaced by MenACYW in 2018 5 . In addition, a catch-up campaign among 14-18-year olds with MenACWY was organized and the vaccine is routinely provided to 14-year olds through the NIP since 2020 6 . For S. pneumoniae , a 7-valent pneumococcal conjugate vaccine (PCV7) was implemented in 2006 and replaced by the 10-valent PCV10 in 2011 7 .…”