Association of Use of a Meningococcus Group B Vaccine With Group B Invasive Meningococcal Disease Among Children in Portugal

Abstract

IMPORTANCE A 4-component meningococcus group B vaccine (4CMenB) is the only vaccine in use to prevent group B invasive meningococcal disease in young children, but no matched controlled studies have evaluated it. OBJECTIVE To determine the association between receipt of 4CMenB and invasive group B meningococcal disease. DESIGN, SETTING, AND PARTICIPANTS Matched incidence density case-control study. Patients presenting from October 2014 to March 2019 were ascertained, with follow-up until death or discharge (last follow-up in June 2019) in 31 pediatric services in Portugal. Children and adolescent residents in Portugal with laboratory-confirmed invasive meningococcal disease were included. Controls, usually 2 per case, with unrelated conditions who were at the same hospital at the same time were matched for sex, age, and residence. EXPOSURES Immunization with 4CMenB, ascertained from the national database (2-4 doses are recommended, depending on age). MAIN OUTCOMES AND MEASURESThe primary outcome was group B invasive meningococcal disease in fully vaccinated cases compared with controls. The secondary outcomes were all serogroup invasive meningococcal disease in fully vaccinated cases compared with controls and group B and all serogroup invasive meningococcal disease in cases compared with controls who received at least 1 vaccine dose. RESULTSOf 117 patients with invasive meningococcal disease, 98 were eligible for inclusion and 82 had group B invasive meningococcal disease; 69 were old enough to have been fully vaccinated and considered protected. Among these 69 cases, the median (interquartile range) age was 24 (4.5-196) months, 42 were male, and the median (interquartile range) duration of hospitalization was 8 (0-86) days. Five of 69 cases (7.2%) and 33 of 142 controls (23.1%) were fully vaccinated (difference, −16.0% [95% CI, −26.3% to −5.7%]; odds ratio [OR], 0.21 [95% CI, 0.08-0.55]). For all serogroup invasive meningococcal disease, 6 of 85 cases (7.1%) and 39 of 175 controls (22.3%) were fully vaccinated (difference, −15.2% [95% CI, −24.3% to −6.1%]; OR, 0.22 [95% CI, 0.09-0.53]). For group B disease, 8 of 82 cases (9.8%) and 50 of 168 controls (29.8%) received at least 1 vaccine dose (difference, −20.0% [95% CI, −30.3% to −9.7%]; OR, 0.18 [95% CI, 0.08-0.44]) and for all serogroup invasive meningococcal disease, 11 of 98 cases (11.2%) and 61 of 201 controls (30.3%) received at least 1 vaccine dose (difference, −19.1% [95% CI, −28.8% to −9.5%]; OR, 0.23 [95% CI, 0.11-0.49]). CONCLUSIONS AND RELEVANCEDuring the first 5 years of vaccine availability in Portugal, vaccination with 4CMenB was less likely among children who developed invasive meningococcal disease compared with matched controls without invasive meningococcal disease. These findings may help inform the use of the 4CMenB vaccine in clinical practice.

A re-assessment of 4CMenB vaccine effectiveness against serogroup B invasive meningococcal disease in England based on an incidence model

“…Our results are also aligned with 4CMenB effectiveness in infants and children reported in two recent observational studies in Italy (two regions: Tuscany and Veneto) and Portugal [ 27 , 28 ]. VE estimates reported in these two studies, which were performed in settings with specifications different to England, confirm once again our re-assessment findings.…”

Recent advances in meningococcal B disease prevention: real-world evidence from 4CMenB vaccination

“…1 ). 57 These estimates were supported by sensitivity analyses including stratification by socioeconomic class, estimation of VE using the screening method, and estimation of VE after removal of the 14-day immune response window. The VE observed in the case-control study was noted to be higher than the strain coverage predicted by MATS (67.9% in isolates over 4 years from 2011-2015 58 ).…”

Looking beyond meningococcal B with the 4CMenB vaccine: the Neisseria effect

“…In a Portuguese RWE study in infants, children, and adolescents, the vaccine effectiveness was 78% for IMD caused by any serogroup. It should be considered that the majority of IMD in Portugal was caused by MenB during the study period (2014–2019) 49 .…”