Retrospective evaluation of control measures for contacts of patient with Marburg hemorrhagic fever.

After an imported case of Marburg hemorrhagic fever was reported in 2008 in the Netherlands, control measures to prevent transmission were implemented. To evaluate consequences of these measures, we administered a structured questionnaire to 130 contacts classified as either having high-risk or low-risk exposure to body fluids of the case-patient; 77 (59.2%) of 130 contacts responded. A total of 67 (87.0%) of 77 respondents agreed that temperature monitoring and reporting was necessary, significantly more often among high-risk than low-risk contacts (p<0.001). Strict compliance with daily temperature monitoring decreased from 80.5% (62/77) during week 1 to 66.2% (51/77) during week 3. Contacts expressed concern about development of Marburg hemorrhagic fever (58.4%, 45/77) and infecting a family member (40.2%, 31/77). High-risk contacts had significantly higher scores on psychological impact scales (p<0.001) during and after the monitoring period. Public health authorities should specifically address consequences of control measures on the daily life of contacts.

Case-based reported mortality associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection in the Netherlands: the 2009-2010 pandemic season versus the 2010-2011 influenza season.

BACKGROUND: In contrast to seasonal influenza epidemics, where the majority of deaths occur amongst elderly, a considerable part of the 2009 pandemic influenza related deaths concerned relatively young people. In the Netherlands, all deaths associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection had to be notified, both during the 2009-2010 pandemic season and the 2010-2011 influenza season. To assess whether and to what extent pandemic mortality patterns were reverting back to seasonal patterns, a retrospective analyses of all notified fatal cases associated with laboratory-confirmed influenza A(H1N1) 2009 virus infection was performed. METHODS: The notification database, including detailed information about the clinical characteristics of all notified deaths, was used to perform a comprehensive analysis of all deceased patients with a laboratory-confirmed influenza A(H1N1) 2009 virus infection. Characteristics of the fatalities with respect to age and underlying medical conditions were analysed, comparing the 2009-2010 pandemic and the 2010-2011 influenza season. RESULTS: A total of 65 fatalities with a laboratory-confirmed influenza A(H1N1) 2009 virus infection were notified in 2009-2010 and 38 in 2010-2011. During the pandemic season, the population mortality rates peaked in persons aged 0-15 and 55-64 years. In the 2010-2011 influenza season, peaks in mortality were seen in persons aged 0-15 and 75-84 years. During the 2010-2011 influenza season, the height of first peak was lower compared to that during the pandemic season. Underlying immunological disorders were more common in the pandemic season compared to the 2010-2011 season (p = 0.02), and cardiovascular disorders were more common in the 2010-2011 season (p = 0.005). CONCLUSIONS: The mortality pattern in the 2010-2011 influenza season still resembled the 2009-2010 pandemic season with a peak in relatively young age groups, but concurrently a clear shift toward seasonal patterns was seen, with a peak in mortality in the elderly, i.e. ≥ 75 years of age.

Experiences of General Practitioners and Practice Assistants during the Influenza A(H1N1) Pandemic in the Netherlands: A Cross-Sectional Survey.

OBJECTIVES: Since few pandemics have occurred since the Spanish influenza pandemic, we should learn from every (mild) pandemic that occurs. The objective of this study was to report on general practitioners' and practice assistants' acceptance of the chosen national policy, and experiences in the Netherlands during the influenza A(H1N1)pdm09 pandemic. METHODS: Data on experience and acceptance of the chosen national policy were obtained by structured questionnaires for general practitioners (n = 372) and practice assistants (n = 503) in April 2010. RESULTS: The primary policy chosen for general practice was not always accepted and complied with by general practitioners, although the communication (of changes) and collaboration with involved organisations were rated as positive. In particular, the advised personal protective measures were difficult to implement in daily work and thus not executed by 44% of general practitioners. Half of the general practitioners were not satisfied with the patient information provided by the government. The influenza A(H1N1) pandemic highly impacted on general practitioners' and practice assistants' workloads, which was not always deemed to be adequately compensated. DISCUSSION: Involvement of general practitioners in future infectious disease outbreaks is essential. This study addresses issues in the pandemic policy which might be critical in a more severe pandemic.

Coverage of the 2011 Q fever vaccination campaign in the Netherlands, using retrospective population-based prevalence estimation of cardiovascular risk-conditions for chronic Q fever.

BACKGROUND: In 2011, a unique Q fever vaccination campaign targeted people at risk for chronic Q fever in the southeast of the Netherlands. General practitioners referred patients with defined cardiovascular risk-conditions (age >15 years). Prevalence rates of those risk-conditions were lacking, standing in the way of adequate planning and coverage estimation. We aimed to obtain prevalence rates retrospectively in order to estimate coverage of the Q fever vaccination campaign. METHODS: With broad search terms for these predefined risk-conditions, we extracted patient-records from a large longitudinal general-practice research-database in the Netherlands (IPCI-database). After validation of these records, obtained prevalence rates (stratified for age and sex) extrapolated to the Q fever high-incidence area population, gave an approximation of the size of the targeted patient-group. Coverage calculation addressed people actually screened by a pre-vaccination Q fever skin test and serology (coverage) and patients referred by their general practitioners (adjusted-coverage) in the 2011 campaign. RESULTS: Our prevalence estimate of any risk-condition was 3.1% (lower-upper limits 2.9-3.3%). For heart valve defects, aorta aneurysm/prosthesis, congenital anomalies and endocarditis, prevalence was 2.4%, 0.6%, 0.4% and 0.1%, respectively. Estimated number of eligible people in the Q fever high-incidence area was 11,724 (10,965-12,532). With 1330 people screened for vaccination, coverage of the vaccination campaign was 11%. For referred people, the adjusted coverage was 18%. Coverage was lowest among the very-old and highest for people aged 50-70 years. CONCLUSION: The estimated coverage of the vaccination campaign was limited. This should be interpreted in the light of the complexity of this target-group with much co-morbidity, and of the vaccine that required invasive pre-vaccination screening. Calculation of prevalence rates of risk-conditions based on the IPCI-database was feasible. This procedure proved an efficient tool for future use, when prevalence estimates for policy, implementation or surveillance of subgroup-vaccination or other health-care interventions are needed.

Implementation of a Q fever vaccination program for high-risk patients in the Netherlands.

BACKGROUND: Between 2007 and 2011 the Netherlands was faced with an unprecedented Q fever outbreak with more than 4000 people affected. Dairy goats were considered the main source of infection. In addition to taking veterinary measures, the Dutch government offered an unlicensed vaccine against the causative bacterium Coxiella burnetii to patient groups at high-risk of Q fever complications. This article describes the complexity of the vaccination program for Q fever in 2010-2011. METHODS: High-risk patients were selected and referred mainly by their general practitioner to a publicly funded centralized screening and vaccination program. In addition, cardiovascular specialists and the public were informed. Patients were screened for previous infection with C. burnetii by serology and skin-tests. Patients who tested positive were excluded from vaccination. RESULTS: Of the 2741 referred high-risk patients (1669 male, 1957 from the high-risk area), 955 were excluded because vaccination was considered unnecessary or the distance to the vaccination clinic too far. 388 (22% of those screened) were excluded because of a positive skin-test or serology. 1368 patients (77% of those screened) were vaccinated between January and June 2011. Two-thirds of the vaccinees reported an adverse event. 89 patients (6.6%) reported serious adverse events. In just one patient, with an injection site reaction, a possible causal relationship was considered. CONCLUSION: This Q fever vaccination program posed challenges to the Dutch Health Care system. Creating clarity on the roles and responsibilities of those involved precluded timely vaccination. Targeting the high-risk population through GPs was challenging but appeared to be efficient. The vaccination was considered to be safe and compliance of the screened patients was high.

Course of pandemic influenza A(H1N1) 2009 virus infection in Dutch patients.

The clinical dynamics of influenza A(H1N1) 2009 infections in 61 laboratory-confirmed Dutch cases were examined. An episode lasted a median of 7·5 days of which 2 days included fever. Respiratory symptoms resolved slowly, while systemic symptoms peaked early in the episode and disappeared quickly. Severity of each symptom was rated highest in the first few days. Furthermore, diarrhoea was negatively associated with viral load, but not with faecal excretion of influenza virus. Cases with comorbidities appeared to have higher viral loads than the cases without, suggesting a less effective immune response. These results complement information obtained through traditional surveillance.

[Hepatitis B revaccination not indicated, even for those at increased risk]. / Revaccinatie tegen hepatitis B niet nodig, ook niet bij personen die door hun werk een verhoogd risico lopen.

OBJECTIVE: To evaluate the long-term protection following hepatitis B vaccination and assess whether revaccination is necessary after 15 years for those who have an increased occupational risk of hepatitis B infection. DESIGN: Systematic literature review METHOD: Medline was searched for English language publications from the period 2002-2008 concerning vaccination against the hepatitis B virus. We included follow-up studies in which the interval between vaccination and titre measurement was at least 4 years. RESULTS: The 22 articles included describe 30 studies. Post-vaccination titre measurement was performed in 10 studies. Four of these described a change from negative to positive testing for anti-hepatitis B core antigen (anti-HBc) (seroconversion) in 0.64% of the 1,880 subjects tested. In the 20 studies in which no post-vaccination titre measurement was carried out, seroconversion was observed for anti-HBc and for hepatitis B surface antigens (HBsAg) in 1.0% and 1.78% of the vaccinees, respectively. These studies were predominantly carried out in high-endemic regions, mostly in newborns of HBsAg positive mothers. Seroconversions were not accompanied by clinical signs or symptoms. In 6 studies there was a follow-up of more than 15 years; the maximum was 23 years. Seroconversions did not appear specifically after a long period of time but were observed independent of time after vaccination. CONCLUSION: Seroconversions occur in < 1% of successfully vaccinated subjects and do not increase after a period of 15 years following vaccination. In all the 23 years of experience with hepatitis B vaccination, it seems to have provided protection. This also applies to those at increased risk. Revaccination after successful vaccination would therefore not seem to be necessary, even after a period of 15 years.