Meningococcal C conjugate vaccine effectiveness before and during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C/cc11, Tuscany, Italy

Research output: Contribution to journalArticle

Abstract

INTRODUCTION: In Tuscany, Italy, where a universal immunization program with monovalent meningococcal C conjugate vaccine (MCC) was introduced in 2005, an outbreak of invasive meningococcal disease (IMD) due to the hypervirulent strain of Neisseria meningitidis C/cc11 occurred in 2015-2016, leading to an immunization reactive campaign using either the tetravalent (ACWY) meningococcal conjugate or the MCC vaccine. During the outbreak, IMD serogroup C (MenC) cases were also reported among vaccinated individuals. This study aimed to characterize meningococcal C conjugate vaccines (MenC-vaccines) failures and to estimate their effectiveness since the introduction (2005-2016) and during the outbreak (2015-2016).

METHODS: MenC cases and related vaccine-failures were drawn from the National Surveillance System of Invasive Bacterial Disease (IBD) for the period 2006-2016. A retrospective cohort-study, including the Tuscany' population of the birth-cohorts 1994-2014, was carried out. Based on annual reports of vaccination, person-years of MenC-vaccines exposed and unexposed individuals were calculated by calendar-year, birth-cohort, and local health unit. Adjusted (by birth-cohort, local health unit, and calendar-year) risk-ratios (ARR) of MenC invasive disease for vaccinated vs unvaccinated were estimated by the Poisson model. Vaccine-effectiveness (VE) was estimated as: VE = 1-ARR.

RESULTS: In the period 2006-2016, 85 MenC-invasive disease cases were reported; 61 (71.8%) from 2015 to 2016. Twelve vaccine failures occurred, all of them during the outbreak. The time-interval from immunization to IMD onset was 20 days in one case, from 9 months to 3 years in six cases, and ≥7 years in five cases. VE was, 100% (95%CI not estimable, p = 0.03) before the outbreak (2006-2014) and 77% (95%CI 36-92, p < 0.01) during the outbreak; VE was 80% (95%CI 54-92, p < 0.01) during the overall period.

CONCLUSIONS: In Tuscany, MenC-vaccine failures occurred exclusively during the 2015-2016 outbreak. Most of them occurred several years after vaccination. VE during the outbreak-period was rather high supporting an effective protection induced by MenC-vaccines.

Original languageEnglish
Pages (from-to)4222-4227
Number of pages6
JournalVaccine
Volume36
Issue number29
DOIs
Publication statusPublished - Jul 5 2018

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Serogroup C Neisseria meningitidis
Neisseria meningitidis
Italy
Disease Outbreaks
serotypes
Vaccines
vaccines
Parturition
Immunization
Vaccination
immunization
serogroup C meningococcal conjugate vaccine
Annual Reports
Immunization Programs
Health
vaccination
Cohort Studies
Retrospective Studies
Odds Ratio

Keywords

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Disease Outbreaks
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Italy/epidemiology
  • Male
  • Meningitis, Meningococcal/epidemiology
  • Meningococcal Vaccines/administration & dosage
  • Middle Aged
  • Neisseria meningitidis, Serogroup C/immunology
  • Retrospective Studies
  • Treatment Failure
  • Young Adult

Cite this

@article{61bd585623c04f0d86036d273da6afe0,
title = "Meningococcal C conjugate vaccine effectiveness before and during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C/cc11, Tuscany, Italy",
abstract = "INTRODUCTION: In Tuscany, Italy, where a universal immunization program with monovalent meningococcal C conjugate vaccine (MCC) was introduced in 2005, an outbreak of invasive meningococcal disease (IMD) due to the hypervirulent strain of Neisseria meningitidis C/cc11 occurred in 2015-2016, leading to an immunization reactive campaign using either the tetravalent (ACWY) meningococcal conjugate or the MCC vaccine. During the outbreak, IMD serogroup C (MenC) cases were also reported among vaccinated individuals. This study aimed to characterize meningococcal C conjugate vaccines (MenC-vaccines) failures and to estimate their effectiveness since the introduction (2005-2016) and during the outbreak (2015-2016).METHODS: MenC cases and related vaccine-failures were drawn from the National Surveillance System of Invasive Bacterial Disease (IBD) for the period 2006-2016. A retrospective cohort-study, including the Tuscany' population of the birth-cohorts 1994-2014, was carried out. Based on annual reports of vaccination, person-years of MenC-vaccines exposed and unexposed individuals were calculated by calendar-year, birth-cohort, and local health unit. Adjusted (by birth-cohort, local health unit, and calendar-year) risk-ratios (ARR) of MenC invasive disease for vaccinated vs unvaccinated were estimated by the Poisson model. Vaccine-effectiveness (VE) was estimated as: VE = 1-ARR.RESULTS: In the period 2006-2016, 85 MenC-invasive disease cases were reported; 61 (71.8{\%}) from 2015 to 2016. Twelve vaccine failures occurred, all of them during the outbreak. The time-interval from immunization to IMD onset was 20 days in one case, from 9 months to 3 years in six cases, and ≥7 years in five cases. VE was, 100{\%} (95{\%}CI not estimable, p = 0.03) before the outbreak (2006-2014) and 77{\%} (95{\%}CI 36-92, p < 0.01) during the outbreak; VE was 80{\%} (95{\%}CI 54-92, p < 0.01) during the overall period.CONCLUSIONS: In Tuscany, MenC-vaccine failures occurred exclusively during the 2015-2016 outbreak. Most of them occurred several years after vaccination. VE during the outbreak-period was rather high supporting an effective protection induced by MenC-vaccines.",
keywords = "Adolescent, Adult, Aged, Aged, 80 and over, Child, Child, Preschool, Disease Outbreaks, Female, Humans, Infant, Infant, Newborn, Italy/epidemiology, Male, Meningitis, Meningococcal/epidemiology, Meningococcal Vaccines/administration & dosage, Middle Aged, Neisseria meningitidis, Serogroup C/immunology, Retrospective Studies, Treatment Failure, Young Adult",
author = "Patrizio Pezzotti and Alessandro Miglietta and Arianna Neri and Cecilia Fazio and Paola Vacca and Fabio Voller and Giovanni Rezza and Paola Stefanelli",
note = "Copyright {\circledC} 2018. Published by Elsevier Ltd.",
year = "2018",
month = "7",
day = "5",
doi = "10.1016/j.vaccine.2018.06.002",
language = "English",
volume = "36",
pages = "4222--4227",
journal = "Vaccine",
issn = "0264-410X",
publisher = "Elsevier BV",
number = "29",

}

TY - JOUR

T1 - Meningococcal C conjugate vaccine effectiveness before and during an outbreak of invasive meningococcal disease due to Neisseria meningitidis serogroup C/cc11, Tuscany, Italy

AU - Pezzotti, Patrizio

AU - Miglietta, Alessandro

AU - Neri, Arianna

AU - Fazio, Cecilia

AU - Vacca, Paola

AU - Voller, Fabio

AU - Rezza, Giovanni

AU - Stefanelli, Paola

N1 - Copyright © 2018. Published by Elsevier Ltd.

PY - 2018/7/5

Y1 - 2018/7/5

N2 - INTRODUCTION: In Tuscany, Italy, where a universal immunization program with monovalent meningococcal C conjugate vaccine (MCC) was introduced in 2005, an outbreak of invasive meningococcal disease (IMD) due to the hypervirulent strain of Neisseria meningitidis C/cc11 occurred in 2015-2016, leading to an immunization reactive campaign using either the tetravalent (ACWY) meningococcal conjugate or the MCC vaccine. During the outbreak, IMD serogroup C (MenC) cases were also reported among vaccinated individuals. This study aimed to characterize meningococcal C conjugate vaccines (MenC-vaccines) failures and to estimate their effectiveness since the introduction (2005-2016) and during the outbreak (2015-2016).METHODS: MenC cases and related vaccine-failures were drawn from the National Surveillance System of Invasive Bacterial Disease (IBD) for the period 2006-2016. A retrospective cohort-study, including the Tuscany' population of the birth-cohorts 1994-2014, was carried out. Based on annual reports of vaccination, person-years of MenC-vaccines exposed and unexposed individuals were calculated by calendar-year, birth-cohort, and local health unit. Adjusted (by birth-cohort, local health unit, and calendar-year) risk-ratios (ARR) of MenC invasive disease for vaccinated vs unvaccinated were estimated by the Poisson model. Vaccine-effectiveness (VE) was estimated as: VE = 1-ARR.RESULTS: In the period 2006-2016, 85 MenC-invasive disease cases were reported; 61 (71.8%) from 2015 to 2016. Twelve vaccine failures occurred, all of them during the outbreak. The time-interval from immunization to IMD onset was 20 days in one case, from 9 months to 3 years in six cases, and ≥7 years in five cases. VE was, 100% (95%CI not estimable, p = 0.03) before the outbreak (2006-2014) and 77% (95%CI 36-92, p < 0.01) during the outbreak; VE was 80% (95%CI 54-92, p < 0.01) during the overall period.CONCLUSIONS: In Tuscany, MenC-vaccine failures occurred exclusively during the 2015-2016 outbreak. Most of them occurred several years after vaccination. VE during the outbreak-period was rather high supporting an effective protection induced by MenC-vaccines.

AB - INTRODUCTION: In Tuscany, Italy, where a universal immunization program with monovalent meningococcal C conjugate vaccine (MCC) was introduced in 2005, an outbreak of invasive meningococcal disease (IMD) due to the hypervirulent strain of Neisseria meningitidis C/cc11 occurred in 2015-2016, leading to an immunization reactive campaign using either the tetravalent (ACWY) meningococcal conjugate or the MCC vaccine. During the outbreak, IMD serogroup C (MenC) cases were also reported among vaccinated individuals. This study aimed to characterize meningococcal C conjugate vaccines (MenC-vaccines) failures and to estimate their effectiveness since the introduction (2005-2016) and during the outbreak (2015-2016).METHODS: MenC cases and related vaccine-failures were drawn from the National Surveillance System of Invasive Bacterial Disease (IBD) for the period 2006-2016. A retrospective cohort-study, including the Tuscany' population of the birth-cohorts 1994-2014, was carried out. Based on annual reports of vaccination, person-years of MenC-vaccines exposed and unexposed individuals were calculated by calendar-year, birth-cohort, and local health unit. Adjusted (by birth-cohort, local health unit, and calendar-year) risk-ratios (ARR) of MenC invasive disease for vaccinated vs unvaccinated were estimated by the Poisson model. Vaccine-effectiveness (VE) was estimated as: VE = 1-ARR.RESULTS: In the period 2006-2016, 85 MenC-invasive disease cases were reported; 61 (71.8%) from 2015 to 2016. Twelve vaccine failures occurred, all of them during the outbreak. The time-interval from immunization to IMD onset was 20 days in one case, from 9 months to 3 years in six cases, and ≥7 years in five cases. VE was, 100% (95%CI not estimable, p = 0.03) before the outbreak (2006-2014) and 77% (95%CI 36-92, p < 0.01) during the outbreak; VE was 80% (95%CI 54-92, p < 0.01) during the overall period.CONCLUSIONS: In Tuscany, MenC-vaccine failures occurred exclusively during the 2015-2016 outbreak. Most of them occurred several years after vaccination. VE during the outbreak-period was rather high supporting an effective protection induced by MenC-vaccines.

KW - Adolescent

KW - Adult

KW - Aged

KW - Aged, 80 and over

KW - Child

KW - Child, Preschool

KW - Disease Outbreaks

KW - Female

KW - Humans

KW - Infant

KW - Infant, Newborn

KW - Italy/epidemiology

KW - Male

KW - Meningitis, Meningococcal/epidemiology

KW - Meningococcal Vaccines/administration & dosage

KW - Middle Aged

KW - Neisseria meningitidis, Serogroup C/immunology

KW - Retrospective Studies

KW - Treatment Failure

KW - Young Adult

U2 - 10.1016/j.vaccine.2018.06.002

DO - 10.1016/j.vaccine.2018.06.002

M3 - Article

C2 - 29895504

VL - 36

SP - 4222

EP - 4227

JO - Vaccine

JF - Vaccine

SN - 0264-410X

IS - 29

ER -