First estimates of influenza vaccine effectiveness among severe influenza cases, France, 2011/12.

Following a suspected virus-vaccine mismatch, the screening method was used to estimate in almost real time the influenza vaccine effectiveness (VE) against severe cases in high-risk individuals. Data on vaccination status were provided by the influenza severe surveillance system and data on vaccination coverage by the National Social Security Scheme. The analysis showed a decline of the vaccine effectiveness in 2011/12 (VE: 30% (95% CI: 22-39)) compared to 2010/11 (VE: 53% (95% CI: 40-67)).

Overrepresentation of influenza A(H1N1)pdm09 virus among severe influenza cases in the 2011/12 season in four European countries.

In France, Ireland, Spain and the United Kingdom, the influenza season 2011/12 started in the final weeks of 2011 and has been dominated by influenza A(H3) viruses with minimal circulation of influenza A(H1N1) pdm09 and B viruses. A relatively greater proportion, however, of influenza A(H1N1)pdm09 viruses were reported in hospitalised laboratory-confirmed influenza cases in four countries. Compared to the season 2010/11, the proportion of subtype A(H3) among hospitalised cases has increased, associated with a larger proportion of cases in the youngest and oldest age groups.

Initial risk perception and feeling of preparedness of primary care physicians regarding the COVID-19 pandemic in Belgium, France and Spain in February 2020.

BACKGROUND: The knowledge of risk perceptions in primary care could help health authorities to manage epidemics. METHODS: A European multi-center cross-sectional study was conducted in France, Belgium and Spain to describe the perceptions, the level of anxiety and the feeling of preparedness of primary healthcare physicians towards the COVID-19 infection at the beginning of the pandemic. The factors associated with the feeling of preparedness were studied using multivariate logistic regressions. RESULTS: A total of 511 physicians participated to the study (response rate: 35.2%). Among them, only 16.3% (n=82) were highly anxious about the pandemic, 50.6% (n=254) had the feeling to have a high level of information, 80.5% (n=409) found the measures taken by the health authorities suitable to limit the spread of COVID-19, and 45.2% (n=229) felt prepared to face the epidemic. Factors associated with feeling prepared were: being a Spanish practitioner (adjusted OR=4.34; 95%CI [2.47; 7.80]), being a man (aOR=2.57, 95%CI [1.69; 3.96]), finding the measures taken by authorities appropriate (aOR=1.72, 95%CI [1.01; 3.00]) and being highly informed (aOR=4.82, 95%CI [2.62; 9.19]). CONCLUSIONS: Regarding the dramatic evolution of the pandemic in Europe in the weeks following the study, it appears that information available at this time and transmitted to the physicians could have given a wrong assessment of the spread and the severity of the disease. It seems essential to better integrate the primary care physicians into the information, training and protection channels. A comparison between countries could help to select the most effective measures in terms of information and communication.

Adult intensive-care patients with 2009 pandemic influenza A(H1N1) infection.

In France, the surveillance of hospitalized cases of pandemic influenza was implemented in July 2009 and restricted to intensive-care unit (ICU) patients in November. We described the characteristics of the 1065 adult patients admitted to ICUs and analysed risk factors for severe outcome (mechanical ventilation or death). Eighty-seven percent of cases were aged 15-64 years. The case-fatality ratio was 20%. The risk for severe outcome increased with age and obesity while this association was negative for chronic respiratory disease. Late antiviral therapy was associated with a severe outcome in ICU patients with risk factors (adjusted OR 2·0, 95% CI 1·4-3·0). This study confirms the considerable contribution of young adults to A(H1N1) 2009 mortality. It shows the role of obesity as an independent risk factor for severe disease, and of early antiviral therapy as a protective factor, at least in patients with risk factors.

Severe hospitalised 2009 pandemic influenza A(H1N1) cases in France, 1 July-15 November 2009.

From 1 July 2009 to 15 November 2009, 244 patients with 2009 pandemic influenza A(H1N1) were admitted to intensive care unit (ICU) and were compared with 514 cases hospitalised in medical wards in France until 2 November 2009. Detailed case-based epidemiological information and outcomes were gathered for all hospitalised cases. Infants and pregnant women are overrepresented among cases admitted to ICU with seven per cent for both groups respectively, and twenty per cent of ICU cases did not belong to a risk group. Chronic respiratory disease was the most common risk factor among cases but obesity (body mass index >or= 30 Kg/m(2)), chronic cardiac disease and immunosuppression were risk factors associated with severe illness after adjustment for age and for other co-morbidities.

Oseltamivir-resistant influenza A(H1N1) viruses detected in Europe during season 2007-8 had epidemiologic and clinical characteristics similar to co-circulating susceptible A(H1N1) viruses.

During the 2007-08 influenza season, high levels of oseltamivir resistance were detected among influenza A(H1N1) viruses ina number of European countries. We used surveillance data to describe influenza A(H1N1) cases for whom antiviral resistance testing was performed. We pooled data from national studies to identify possible risk factors for infection with a resistant virus and to ascertain whether such infections led to influenza illness of different severity. Information on demographic and clinical variables was obtained from patients or their physicians. Odds ratios for infection with an oseltamivir resistant virus and relative risks for developing certain clinical outcomes were computed and adjusted through multivariable analysis. Overall, 727 (24.3%) of 2,992 tested influenza A(H1N1) viruses from 22 of 30 European countries were oseltamivir-resistant. Levels of resistance ranged from 1% in Italy to 67% in Norway. Five countries provided detailed case-based data on 373 oseltamivir resistant and 796 susceptible cases. By multivariable analysis, none of the analysed factors was significantly associated with an increased risk of infection with anoseltamivir-resistant virus. Similarly, infection with an oseltamivir-resistant virus was not significantly associated with a different risk of pneumonia, hospitalisation or any clinical complication. The large-scale emergence of oseltamivir-resistant viruses in Europe calls for a review of guidelines for influenza treatment.

[Pertussis: data collection and vaccinal strategy]. / La coqueluche : collecte de données et choix des stratégies vaccinales.

UNLABELLED: Renacoq is a pediatric hospital-based surveillance network in France, set up in April 1996 to monitor the trend of pertussis among children and the impact of vaccination strategies. METHOD: The authors studied the link between data collection and public health policy. Microbiologists from 43 hospitals notify diagnosis of pertussis among children less than 16 years of age. Pediatricians complete a questionnaire for infants less than 6 months of age fulfilling the case definitions. Positive cultures are sent to the National reference laboratory to validate biological results. Data collected from 1996 to 2007 was analyzed, as well as its interaction with changes in pertussis vaccine policy. RESULTS: The introduction of adolescent and adult boosters was largely supported by Renacoq data but this was not the case for interruption of whole cell vaccine use. The impact of adolescent booster is moderate because of a limited vaccine coverage. There was no observed impact of the adult booster but the coverage is very weak. The introduction and then the sole use of acellular vaccine did not have any impact on Renacoq data. DISCUSSION: The study illustrates the burden of the disease among infants and the link between surveillance data collection and public health decision. It highlights the difficulty to implement new vaccine strategies and the importance of data collection, stressing the need for a better consideration of hospital practitioners involved in public healthcare surveillance.

Baseline characteristics and clinical symptoms related to respiratory viruses identified among patients presenting with influenza-like illness in primary care.

OBJECTIVES: We aimed to identify patients' clinical characteristics associated with respiratory viruses identified among patients presenting with influenza-like illness (ILI). METHODS: A sample of patients of all ages presenting with ILI was included by physicians of the French Sentinelles network during two seasons (2015/16 and 2016/17). Nasopharyngeal samples were tested for the presence of influenza virus (IV), respiratory syncytial virus (RSV), human rhinovirus (HRV) and human metapneumovirus (HMPV). Patients' characteristics associated with each of the four virus classes were studied using multivariate logistic regressions. RESULTS: A total of 5859 individuals were included in the study: 48.0% tested positive for IV, 7.9% for HRV, 7.5% for RSV and 4.1% for HMPV. Cough was associated with IV (OR 2.14, 95% CI 1.81-2.52) RSV (OR 2.52, 95% CI 1.75-3.74) and HMPV detection (OR 2.15, 95% CI 1.40-3.45). Rhinorrhoea was associated mainly with HRV detection (OR 1.75, 95% CI 1.34-2.32). Headache was associated with IV detection (OR 1.75, 95% CI 1.34-2.32), whereas absence of headache was associated with RSV and HMPV detection. Dyspnoea was associated with RSV detection (OR 2.33, 95% CI 1.73-3.12) and absence of dyspnoea with IV detection. Conjunctivitis was associated with IV detection (OR 1.27, 95% CI 1.08-1.50). Some associations were observed only in children: dyspnoea and cough with RSV detection (age <5 years), conjunctivitis with IV detection (age <15 years). Period of onset of symptoms differed among aetiological diagnoses. Seasonal influenza vaccination decreased the risk of IV detection (OR, 0.67, 95% CI 0.51-0.86). CONCLUSIONS: This study allowed the identification of symptoms associated with several viral aetiologies in patients with ILI. A proper knowledge and understanding of these clinical signs may improve the medical management of patients.

[Modelling the impact of vaccination on the epidemiology of varicella zoster virus]. / Modélisation de l'impact de la vaccination sur l'épidémiologie de la varicelle et du zona.

BACKGROUND: The soon to come the availability of a combined MMR-varicella vaccine has re-stimulated the debate around universal infant vaccination against varicella. In France, the incidence of varicella is estimated at about 700,000 cases per year, with approximately 3500 hospitalisations and 15-25 deaths, the latter mainly occurring in those over 15years. Vaccination would certainly decrease the overall incidence of the disease but concerns about vaccination leading to a shift in the average age at infection followed by an increase in incidence of severe cases and congenital varicella, still remain. In order to provide support for decision-making, a dynamic mathematical model of varicella virus transmission was used to predict the effect of different vaccination strategies and coverages on the epidemiology of varicella and zoster. METHODS: A deterministic realistic age-structured model was adapted to the French situation. Epidemiological parameters were estimated from literature or surveillance data. Various vaccine coverages and vaccination strategies were investigated. A sensitivity analysis of varicella incidence predictions was performed to test the impact of changes in the vaccine parameters and age-specific mixing patterns. RESULTS: The model confirms that the overall incidence and morbidity of varicella would likely be reduced by mass vaccination of 12-month-old children. Whatever the coverage and the vaccine strategy, the vaccination will cause a shift in age distribution with, for vaccination coverage up to at least 80% in the base-case analysis, an increased morbidity among adults and pregnant women. However, the total number of deaths and hospitalisations from varicella is predicted to remain below that expected without vaccination. The model is very sensitive to the matrix of contacts used and to the parameters describing vaccine effectiveness. Zoster incidence will increase over a number of decades followed by a decline to below prevaccination levels. CONCLUSION: Mass varicella vaccination, in France, will result in an overall reduction of varicella incidence but will cause a shift in age distribution with an increase in adult cases. Due to the uncertainties in key parameters values, the exact magnitude of this shift is difficult to assess.

Nosocomial infections and community clusters of pertussis in France, 2000-2005.

Pertussis is not a notifiable disease in France. In addition to a paediatric hospital sentinel surveillance system, pertussis epidemiological data have, since 1996, been gathered through the voluntary notification of community clusters by general practitioners, and since 2001 by the statutory notification of nosocomial infection to the relevant local health authority. The local health authority forwards the information to the French National Institute for Surveillance (InVS). The objective of this study was to analyse pertussis data outside the routine paediatric hospital sentinel surveillance system. We gathered all the information concerning healthcare-associated infections and community clusters of pertussis (specific forms, investigation reports, emails etc.) reported to the InVS between 2000 and 2005. The InVS received and analysed 67 reports with a total of 595 cases. Almost half of the reports (n=31) came from hospitals, and healthcare workers were usually first affected. Control measures were put in place in 22 healthcare facilities and the average duration of an outbreak episode was 48 days. Outside healthcare facilities, clusters were reported also from 17 daycare facilities or schools and five workplaces. Among the 595 cases, six deaths occurred in children under seven months of age. Pertussis is still occurring in France and affects those who are not or who are no longer protected by the vaccine. Infection of infants within the household could be prevented if their parents and siblings were immunised. The number and size of pertussis clusters in hospitals could be reduced through immunisation of health staff, and timely and adequate outbreak management.

[Contribution of simulation models to public health decisions: the influenza pandemic]. / Apport des modélisations des épidémies dans la décision de santé publique: exemple de la pandémie grippale.

The influenza pandemic threat had led to an increased awareness and several countries have used models to assess the impact of control measures on the influenza pandemic. We reviewed the publications related to simulation models since 2003 and discuss their contribution to public health decision in France. The studies conclude that rapid control measures with a high coverage can stop a nascent pandemic. This can be applied to a community with a limited importation of cases but the quantity of antiviral drug needed would become rapidly prohibitive in case of further multiple foci. Both prophylactic and curative use of antiviral drugs can reduce the number of hospitalizations and the incidence during a pandemic. Finally, if a single strategy is sufficient to limit an outbreak in case of a moderate reproductive number, a combination of control measures is mandatory in case of highly transmissible strains. The results of these studies were taken in account to implement guidelines concerning antiviral drug use, in France.

[Principles of an outbreak investigation in public health practice]. / Les principes de l'investigation d'une épidémie dans une finalité de santé publique.

An outbreak (or epidemic) is a higher number of cases of a given disease in a given population and time interval. A timely investigation has for aim to identify the source and vehicle of the outbreak and provides unique opportunities to better understand its occurrence and the role of contributing risk factors to implement the most appropriate measures to control it and prevent further recurrences. The investigation of an outbreak is based on a multidisciplinary approach (clinical, epidemiological, environmental, and microbiological) with a descriptive and analytical (hypothesis testing) phase. In this article, we describe the methodological approach of a field outbreak investigation illustrated by examples taken from our experience. The investigation includes the following steps: establishing the existence of the outbreak; defining the disease; finding cases; describing cases by time, place, and person characteristics; establishing a hypothesis related to the mode of occurrence; testing the hypotheses; conducting an environmental investigation; conducting a microbiological investigation; controlling the outbreak, preventing further occurrences, and writing an investigation report to share experience with the public health and scientific community. The investigation of an outbreak is an evolving process: information gathered or conclusions made at a given stage must be fully used for following steps. The social, institutional, and political background associated with outbreaks usually makes their investigation complex and should be taken into account. The earlier the outbreak is detected and investigated in close relation with public health authorities, the greater will be the potential preventive impact of control measures.

Absence of infection in asymptomatic contacts of index SARS case in France.

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

Absence of infection in asymptomatic contacts of index SARS case in France.

The first case of severe acute respiratory syndrome (SARS) in France was diagnosed in March 2003. We conducted a serological survey to assess whether or not asymptomatic persons who had been in contact with this patient during his infectious stage had been infected. They were interviewed and asked to provide a blood sample for SARS coronavirus immunoglobulin G antibody testing. Despite the likely high infectivity of the SARS patient, no asymptomatic SARS infection was found in any of the 37 contacts included. These findings support a SARS case definition that is essentially based on clinical and epidemiological assessment, should SARS re-emerge.

[Cases of pertussis among healthcare workers in a maternity ward: management of a health alert]. / Cas de coqueluche parmi le personnel d'un service de maternité: gestion d'une alerte sanitaire.

UNLABELLED: Pertussis is a highly contagious acute respiratory tract infection, with a poor prognosis in non-vaccinated new-borns. OBJECTIVES: The authors had for aim to investigate an epidemic of 5 pertussis cases among health care workers (HCW) in our maternity ward with potential exposure of new-borns and to evaluate HCW compliance and experience gain. METHODS: A retrospective study was made using a questionnaire with HCW on preventive measures taken (antibiotic prophylaxis with erythromycin and wearing a mask). RESULTS: Two hundred and thirty-eight patients were warned of a potential pertussis contamination. No nosocomial case was detected among patients or their new borns. Ten proved or probable cases were identified among 101 HCW having answered (N=101/210, 48%). Sixty percent of HCW people followed the antibiotic treatment and 85% wore a mask among whom 46% adequately. Non-compliance factors were mainly related to adverse effects (41%), delayed information (41%), and false vaccine protection (22%). Crisis communication was felt as unsatisfactory for 72% of HCW and recommendations not adapted for 39% of the staff. CONCLUSION: This survey points out the difficulty of managing a pertussis alert in a medical ward.

[Action to be taken when facing one or more cases of whooping-cough]. / Conduite à tenir devant un ou plusieurs cas de coqueluche.

The evolution of the epidemiology of pertussis, new licensed macrolides and vaccines, new recommendations for vaccination among adolescents and adults need an update of the French guidelines for prevention of the disease around one or grouped cases of the disease. A particular attention should be raised to the diagnosis of whooping cough in adults who are presently the main reservoir of Bordetella pertussis. Whooping cough in adults presents as an unexplained prolonged cough with nocturnal exacerbation witch accounts for most of the contaminations of young infants. A bacteriological confirmation of pertussis should be provided before implementation of preventive measures: culture and PCR are presently the gold standard for the diagnosis of pertussis in infants, children and even adults who have been coughing for less than 20 days. Later on, serology (Elisa, immuno-empreinte) is the only technique available, but cannot be interpreted if the patient has been vaccinated less than one year ago. Infants under three months should be admitted to hospital and every case submitted to respiratory isolation. Eviction from the community should be pronounced within the five first days following the onset of an effective antibiotic treatment. New macrolides should be favoured: clarithromycin for seven days or azithromycin for five days. Household contacts should be given the same prophylactic antibiotic treatment: children and adolescent not correctly immunized, parents of the index case as adults parents of not or not completely immunized infants. The vaccination program of the household should be updated. The same measures should be applied in case of grouped cases (at least two contemporary or consecutive cases in the same area). In that case, the Public Health System doctors should be involved in the investigation and the classification of the cases. The close contacts not or not completely immunized should be prescribed and antibiotic prophylaxis and an update of their vaccination program. Among the occasional contacts, high-risk people only should be treated. In the day care centres an antibiotic prophylaxis should be given to children who have received less than four vaccine shots against pertussis and to the personnel contact to the cases as well. In the schools, the antibiotic prophylaxis should be prescribed to all children of the classroom(s) not completely vaccinated and to the teacher(s) as well. In the boarding schools and institutions with handicapped children, antibiotic prophylaxis could be applied to every member if the pertussis vaccine coverage is at less than 50%. In hospitals, coughing personnel should wear masks and investigations towards pertussis should be performed in people with a more than seven day unexplained cough. Preventive measures should be applied in case of confirmation of pertussis.

Measles in France: the epidemiological impact of suboptimal immunisation coverage.

The promotion of immunisation in France since 1983 has resulted in a 97% reduction in morbidity and a reduction of 60% of mortality. However, the stable and sub-optimal coverage around 84% leads to a shift in higher age groups, where complications are more frequent and serious. The proportion of those aged over 10 years was 13% in 1985 and reached 48% in 1997, the transmission of measles being maintained in France. To eliminate the disease, vaccine coverage with 2 doses and over 95% would be necessary.

Herpes zoster: Burden of disease in France.

This work provides estimates of HZ incidence and HZ-related hospitalization and mortality rates in France, where no immunization programme has been implemented. Herpes zoster data was obtained from the Sentinelles surveillance general practitioners (GPs) network, the PMSI Data processing centre for hospital discharges and from the French National Mortality Database (INSERM CépiDC). The yearly HZ incidence rate averaged 382 cases per 100,000 inhabitants (95% CI 364-405) and exponentially increased with age. The annual rates of hospitalizations and mortality due to HZ varied from 4.14±0.32 to 14.42±0.39 and from 0.11±0.03 to 0.29±0.04 per 100,000 inhabitants, respectively, depending on whether HZ was coded in a 'primary' or 'primary or associated' diagnosis. One or more factors of immunodepression occurred in 43.4% of hospitalized cases and in 21.6% HZ-related deaths.

Konzo outbreak, in the south-west of the Democratic Republic of Congo, 1996.

In August 1996, cases of poliomyelitis were reported in Kahemba zone, in the south-west of the Democratic Republic (DR) of Congo. The diagnosis was reviewed and charged to Konzo, a spastic paraparesis attributed to food cyanide intoxication. In order to describe the phenomena, a community-based survey took place and found 237 people affected. The highest prevalence was found in the most isolated part of the zone. The patients suffered from an isolated non-progressive spastic paraparesis of abrupt onset. Children and women were the most affected groups, especially women after childbirth. Most of the patients developed the disease after 1990 with 101 cases in 1996. Cassava processing was the same over time and in all the villages. The study did not fully explain the increased number of cases in 1996 but suggested that complementary investigations regarding micronutrient intakes, especially vitamin A, would be necessary.