Use of MenACWY-CRM in adolescents in the United States

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

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.

Surveillance of adverse events following vaccination in the French armed forces, 2011-2012

OBJECTIVES

French military personnel are subject to a compulsory vaccination schedule. The aim of this study was to present the results of surveillance of vaccine adverse events (VAEs) reported from 2011 to 2012 in the French armed forces.

STUDY DESIGN

VAEs were surveyed among all French armed forces from 2011 to 2012 by the epidemiological departments of the military health service. For each case, a notification form providing patient and clinical information was provided.

METHODS

Case definitions were derived from the French drug safety guidelines. Three types of VAE were considered: non-serious, serious and unexpected. Incidence rates were calculated by relating VAEs to the number of vaccine doses delivered.

RESULTS

In total, 161 VAE cases were reported. The overall VAE reporting rate was 24.6 VAEs per 100,000 doses, and the serious VAE rate was 1.3 per 100,000 doses (nine cases). The serious VAEs included two cases of Guillain-Barré syndrome, one case of optic neuritis, one case of a meningeal-like syndrome, one case of rheumatoid purpura, one case of acute asthma and three cases of fainting. The highest rates of VAE were observed with the Bacille Calmette-Guérin vaccine (BCG) (482.3 per 100,000 doses), inactivated diphtheria-tetanus-poliovirus with acellular pertussis vaccine (dTap-IPV) (106.1 per 100,000 doses) and meningococcal quadrivalent glycoconjugate vaccine (MenACWY-CRM) (39.3 per 100,000 doses).

CONCLUSIONS

The global rates of VAE observed in 2011 and 2012 confirm the increase that has been observed since 2009 in the French armed forces, which could reflect improved practitioner awareness about VAEs and the use of certain vaccines added to the vaccination schedule recently (dTap-IPV in 2008 and MenACWY-CRM in 2010). VAEs appear to be relatively rare, particularly serious VAEs, which indicates acceptable tolerance of vaccines.