Evaluating the effect of targeted strategies as control tools for hypervirulent meningococcal C outbreaks: a case study from Tuscany, Italy, 2015 to 2016.

BackgroundMeningococcus (Neisseria meningitidis) is the causative bacteria of invasive meningococcal disease (IMD), a major cause of meningitis and sepsis. In 2015-16, an outbreak caused by serogroup C meningococci (MenC), belonging to the hyperinvasive strain ST-11(cc-11), resulted in 62 IMD cases in the region of Tuscany, Italy.AimWe aimed to estimate the key outbreak parameters and assess the impact of interventions used in the outbreak response.MethodsWe developed a susceptible-carrier-susceptible individual-based model of MenC transmission, accounting for transmission in households, schools, discos/clubs and the general community, which was informed by detailed data on the 2015-16 outbreak (derived from epidemiological investigations) and on the implemented control measures.ResultsThe outbreak reproduction number (Re) was 1.35 (95% prediction interval: 1.13-1.47) and the IMD probability was 4.6 for every 1,000 new MenC carriage episodes (95% confidence interval: 1.8-12.2). The interventions, i.e. chemoprophylaxis and vaccination of close contacts of IMD cases as well as age-targeted vaccination, were effective in reducing Re and ending the outbreak. Case-based interventions (including ring vaccination) alone would have been insufficient to achieve outbreak control. The definition of age groups to prioritise vaccination had a critical impact on the effectiveness and efficiency of control measures.ConclusionsOur findings suggest that there are no effective alternatives to widespread reactive vaccination during outbreaks of highly transmissible MenC strains. Age-targeted campaigns can increase the effectiveness of vaccination campaigns. These results can be instrumental to define effective guidelines for the control of future meningococcal outbreaks caused by hypervirulent strains.

[Serogroup C invasive meningococcal disease in the post-vaccine era and vaccine failures]. / Enfermedad meningocócica invasiva por serogrupo C en la era posvacunal y fallos vacunales.

INTRODUCTION: The incidence of serogroup C invasive meningococcal disease (IMD) has decreased since the introduction of systematic vaccination in 2000. The aim of this study is to determine the number of serogroup C IMD cases diagnosed since then and the vaccine failures. PATIENTS AND METHODS: A retrospective analysis was performed on patients diagnosed with IMD by culture or polymerase chain reaction (PCR) in a maternity and childhood hospital in Barcelona between 2001 and 2018. An analysis was made of the number of vaccine doses and the age received, as well as on the medical records and vaccine cards. RESULTS: There were 128 confirmed cases of IMD (7.1 cases/year; 70.3 in <5 years). The serogroup was studied in 125 (97.6%) cases, in which 103 (82.4%) were B, 10 (8%) were C, one (0.8%) was 29E, and one (0.8%) was Y, and only 10 (8%) were not able to be serogrouped. Of the 10 patients with serogroup C, 4 were not vaccinated, and in 3, the course was not complete as regards the number of doses. The other 3 received the complete course according to age and current calendar, and thus were considered vaccine failures. A total of 6 patients died (mortality rate: 4.7%), 5 due to serogroup B (mortality: 4.8%), and one due to serogroup C (mortality: 10%). CONCLUSIONS: Serogroup C only represented 8% of IMD cases in the period studied, with 30% of cases due to this serogroup being vaccine failures.

Sordera aguda y ataxia de origen vestibular en paciente con meningitis por Meningococo Serogrupo C

La meningitis bacteriana aguda es una emergencia infectológica ya que puede ocasionar secuelas graves o incluso la muerte. Es rara la presentación de este cuadro con sordera súbita y ataxia. Se presenta el caso de una adolescente del sexo femenino de 14 años, que presentó meningitis bacteriana por meningococo serogrupo C con ataxia vestibular y sordera súbita, que fue tratada con corticoides y pentoxifilina, además de antibióticos para la infección de base. La recuperación de la audición no fue adecuada y persistió con sordera e hipoacusia severa unilateral y ataxia vestibular persistente e inhabilitante.

Acute bacterial meningitis is an infectious emergency as it can lead to serious sequelae or even death. The presentation of this condition with sudden deafness and ataxia is rare. We present the case of a 14-year old female adolescent, who presented with vestibular ataxia and sudden deafness and was subsequently diagnosed with bacterial meningitis due to serogroup C meningococcus. She was treated with corticosteroids and pentoxifylline, in addition to antibiotics, for the baseline infection. Hearing recovery was not adequate; she persisted with severe deafness, unilateral hearing loss and persistent and disabling vestibular ataxia.