Diphtheria in Mayotte, 2007-2015.

Epidemiology of diphtheria in the southwestern Indian Ocean is poorly documented. We analyzed 14 cases of infection with toxigenic Corynebacterium diphtheriae reported during 2007-2015 in Mayotte, a French department located in this region. Local control of diphtheria is needed to minimize the risk for importation of the bacterium into disease-free areas.

Intensive care unit surveillance of influenza infection in France: the 2009/10 pandemic and the three subsequent seasons.

During the 2009/10 pandemic, a national surveillance system for severe influenza cases was set up in France. We present results from the system's first four years. All severe influenza cases admitted to intensive care units (ICU) were reported to the Institut de Veille Sanitaire using a standardised form: data on demographics, immunisation and virological status, risk factors, severity (e.g. acute respiratory distress syndrome (ARDS) onset, mechanical ventilation, extracorporeal life support) and outcome. Multivariate analysis was performed to identify factors associated with ARDS and death. The number of confirmed influenza cases varied from 1,210 in 2009/10 to 321 in 2011/12. Most ICU patients were infected with A(H1N1)pdm09, except during the 2011/12 winter season when A(H3N2)-related infections predominated. Patients' characteristics varied according to the predominant strain. Based on multivariate analysis, risk factors associated with death were age ≥ 65 years, patients with any of the usual recommended indications for vaccination and clinical severity. ARDS occurred more frequently in patients who were middle-aged (36-55 years), pregnant, obese, or infected with A(H1N1)pdm09. Female sex and influenza vaccination were protective. These data confirm the persistent virulence of A(H1N1)pdm09 after the pandemic and the heterogeneity of influenza seasons, and reinforce the need for surveillance of severe influenza cases.

Cost-effectiveness of a herpes zoster vaccination program among the French elderly people.

A vaccine against herpes zoster (HZ) and its complications has already proven safe and effective against infection and pain and against the related deterioration of quality of life in the elderly. In order to inform the vaccination decision-making process regarding inclusion of this vaccine in the French immunization schedule, we assessed the cost-effectiveness of several vaccination scenarios, compared to no vaccination. We chose to use a previously published Markov model. Starting vaccination in elderly individuals aged 65, 70 and 75 y old appears more cost-effective than vaccination for those aged 60 y old, with a cost-effectiveness ratio between 30,000 and 35,000 euros per quality-adjusted-life year (QALY) gained for the first 3 age groups versus 54,500 €; for the latter group. These results largely contributed to the recommendation to include the HZ vaccination in the French immunization schedule for people aged between 65 and 74 y old in France.

Impact of influenza vaccination on mortality in the French elderly population during the 2000-2009 period.

With declining influenza vaccine coverage in the elderly in recent years in France, we aimed at assessing the benefits of seasonal influenza vaccination, based on available data for observed mortality, vaccine coverage and vaccine effectiveness. To estimate the annual number of deaths avoided by vaccination in the people aged 65 years or more, we used the following three elements: an estimate of vaccine effectiveness against all-cause mortality (based on the "difference-in-differences" approach which reduces the usual bias seen in observational studies), French mortality data and vaccine coverage data. We estimated an annual average of 2000 deaths currently avoided through vaccination and a vaccine effectiveness of 35% against influenza-attributable deaths. Around 2650 vaccinations are needed to prevent a death among the elderly. Communicating these results should help restoring at-risk populations' confidence in influenza vaccination.

Monitoring the Impact of Vaccination on Pertussis in Infants Using an Active Hospital-based Pediatric Surveillance Network: Results from 17 Years' Experience, 1996-2012, France.

BACKGROUND: Despite a high vaccine coverage in France in children, a resurgence of pertussis in infants too young to be protected by vaccination was observed in the 1990 s, leading to additional vaccination strategies in older age groups. This article describes the epidemiologic trends and characteristics of cases among infants 0-5 months of age during 17 years of pertussis surveillance through Renacoq. METHODS: Renacoq is a sentinel hospital-based voluntary surveillance network covering about 30% of hospitalized pertussis pediatric cases. It includes microbiologists and pediatricians from 42 large hospitals. RESULTS: Since March 1996, the network has described 2227 cases of pertussis in infants aged 0-5 months of whom 67.7% were infants 0-2 months of age. Four epidemic peaks occurred. The estimated national average incidence rate for the children aged 0-2 months decreased significantly between 1996-1998 and 2008-2012 from 264 to 179 per 100,000. Globally, 18.4% of cases were admitted to an intensive care unit, and the average case fatality ratio was 1%. Two-thirds (67.1%) of infants aged 3-5 months were not correctly vaccinated according to age. Parents accounted for 41-57% of the infections and siblings for 17-24%. CONCLUSIONS: Renacoq data confirmed the risk for young children and the need of timely pertussis vaccination. Parents and sibling remain the main source of infection, despite addition of boosters targeting sibling and parents. Improving vaccination coverage in adults in contact with young infants is needed. The continuation of Renacoq surveillance will allow monitoring the impact of additional vaccination strategies.