Patrizio Pezzotti1, Alessandro Miglietta2, Arianna Neri1, Cecilia Fazio1, Paola Vacca1, Fabio Voller3, Giovanni Rezza1, Paola Stefanelli4. 1. Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy. 2. Regional Health Agency of Tuscany, Epidemiologic Observatory, Florence, Italy; Units of Epidemiology and Preventive Medicine, Central Tuscany Health Authority, Florence, Italy. 3. Regional Health Agency of Tuscany, Epidemiologic Observatory, Florence, Italy. 4. Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy. Electronic address: paola.stefanelli@iss.it.
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.
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.
Authors: Myint Tin Tin Htar; Sally Jackson; Paul Balmer; Lidia Cristina Serra; Andrew Vyse; Mary Slack; Margarita Riera-Montes; David L Swerdlow; Jamie Findlow Journal: BMC Public Health Date: 2020-12-09 Impact factor: 3.295
Authors: Milou Ohm; Susan J M Hahné; Arie van der Ende; Elisabeth A M Sanders; Guy A M Berbers; Wilhelmina L M Ruijs; Nina M van Sorge; Hester E de Melker; Mirjam J Knol Journal: Clin Infect Dis Date: 2022-07-06 Impact factor: 20.999
Authors: S Igidbashian; L Bertizzolo; A Tognetto; C Azzari; P Bonanni; P Castiglia; M Conversano; S Esposito; G Gabutti; G Icardi; P L Lopalco; F Vitale; S Parisi; G Checcucci Lisi Journal: J Prev Med Hyg Date: 2020-07-04