School closures during the 2009 influenza pandemic: national and local experiences.

BACKGROUND: School closure is a non-pharmaceutical intervention that was considered in many national pandemic plans developed prior to the start of the influenza A(H1N1)pdm09 pandemic, and received considerable attention during the event. Here, we retrospectively review and compare national and local experiences with school closures in several countries during the A(H1N1)pdm09 pandemic. Our intention is not to make a systematic review of country experiences; rather, it is to present the diversity of school closure experiences and provide examples from national and local perspectives. METHODS: Data were gathered during and following a meeting, organized by the European Centres for Disease Control, on school closures held in October 2010 in Stockholm, Sweden. A standard data collection form was developed and sent to all participants. The twelve participating countries and administrative regions (Bulgaria, China, France, Hong Kong Special Administrative Region (SAR), Italy, Japan, New Zealand, Serbia, South Africa, Thailand, United Kingdom, and United States) provided data. RESULTS: Our review highlights the very diverse national and local experiences on school closures during the A(H1N1)pdm09 pandemic. The processes including who was in charge of making recommendations and who was in charge of making the decision to close, the school-based control strategies, the extent of school closures, the public health tradition of responses and expectations on school closure varied greatly between countries. Our review also discusses the many challenges associated with the implementation of this intervention and makes recommendations for further practical work in this area. CONCLUSIONS: The single most important factor to explain differences observed between countries may have been the different public health practises and public expectations concerning school closures and influenza in the selected countries.

Modelling the risk-benefit impact of H1N1 influenza vaccines.

BACKGROUND: Shortly after the H1N1 influenza virus reached pandemic status in June 2009, the benefit-risk project team at the European Medicines Agency recognized this presented a research opportunity for testing the usefulness of a decision analysis model in deliberations about approving vaccines soon based on limited data or waiting for more data. Undertaken purely as a research exercise, the model was not connected to the ongoing assessment by the European Medicines Agency, which approved the H1N1 vaccines on 25 September 2009. METHODS: A decision tree model constructed initially on 1 September 2009, and slightly revised subsequently as new data were obtained, represented an end-of-September or end-of-October approval of vaccines. The model showed combinations of uncertain events, the severity of the disease and the vaccines' efficacy and safety, leading to estimates of numbers of deaths and serious disabilities. The group based their probability assessments on available information and background knowledge about vaccines and similar pandemics in the past. RESULTS: Weighting the numbers by their joint probabilities for all paths through the decision tree gave a weighted average for a September decision of 216 500 deaths and serious disabilities, and for a decision delayed to October of 291 547, showing that an early decision was preferable. CONCLUSIONS: The process of constructing the model facilitated communications among the group's members and led to new insights for several participants, while its robustness built confidence in the decision. These findings suggest that models might be helpful to regulators, as they form their preferences during the process of deliberation and debate, and more generally, for public health issues when decision makers face considerable uncertainty.

The consortium for the standardization of influenza seroepidemiology (CONSISE): a global partnership to standardize influenza seroepidemiology and develop influenza investigation protocols to inform public health policy.

CONSISE - The consortium for the Standardization of Influenza Seroepidemiology - is a global partnership to develop influenza investigation protocols and standardize seroepidemiology to inform health policy. This international partnership was formed in 2011 and was created out of a need, identified during the 2009 H1N1 pandemic, for timely seroepidemiological data to better estimate pandemic virus infection severity and attack rates to inform policy decisions. CONSISE has developed into a consortium of two interactive working groups: epidemiology and laboratory, with a steering committee composed of individuals from several organizations. CONSISE has had two international meetings with more planned for 2013. We seek additional members from public health agencies, academic institutions and other interested parties.

Influenza serological studies to inform public health action: best practices to optimise timing, quality and reporting.

BACKGROUND: Serological studies can detect infection with a novel influenza virus in the absence of symptoms or positive virology, providing useful information on infection that goes beyond the estimates from epidemiological, clinical and virological data. During the 2009 A(H1N1) pandemic, an impressive number of detailed serological studies were performed, yet the majority of serological data were available only after the first wave of infection. This limited the ability to estimate the transmissibility and severity of this novel infection, and the variability in methodology and reporting limited the ability to compare and combine the serological data. OBJECTIVES: To identify best practices for conduct and standardisation of serological studies on outbreak and pandemic influenza to inform public policy. METHODS/SETTING: An international meeting was held in February 2011 in Ottawa, Canada, to foster the consensus for greater standardisation of influenza serological studies. RESULTS: Best practices for serological investigations of influenza epidemiology include the following: classification of studies as pre-pandemic, outbreak, pandemic or inter-pandemic with a clearly identified objective; use of international serum standards for laboratory assays; cohort and cross-sectional study designs with common standards for data collection; use of serum banks to improve sampling capacity; and potential for linkage of serological, clinical and epidemiological data. Advance planning for outbreak studies would enable a rapid and coordinated response; inclusion of serological studies in pandemic plans should be considered. CONCLUSIONS: Optimising the quality, comparability and combinability of influenza serological studies will provide important data upon emergence of a novel or variant influenza virus to inform public health action.

Comment on "Seroevidence for H5N1 influenza infections in humans: meta-analysis".

A better understanding of the severity of H5N1 in humans is needed. Wang et al. (Brevia, 23 March 2012, p. 1463; published online 23 February 2012) overinterpret the results of seroprevalence studies and take too little account of underlying uncertainties. Although the true risk of death from H5N1 infection will likely be lower than the 60% of reported laboratory-confirmed cases, there is little evidence of millions of missed infections.

Developing pandemic preparedness in Europe in the 21st century: experience, evolution and next steps.

PROBLEM: Improving pandemic planning and preparedness is a challenge in Europe, a diverse region whose regional bodies (the Regional Office for Europe of the World Health Organization [WHO], the European Commission and the European Centre for Disease Prevention and Control) have overlapping roles and responsibilities. APPROACH: European pandemic preparedness indicators were used to develop an assessment tool and procedure based on the 2005 global WHO checklist for pandemic preparedness. These were then applied to Member States of WHO's European Region, initially as part of structured national assessments conducted during short visits by external teams. LOCAL SETTING: Countries in WHO's European Region. RELEVANT CHANGES: From 2005 to 2008, 43 countries underwent a pandemic preparedness assessment that included a short external assessment visit by an expert team. These short visits developed into a longer self-assessment procedure involving an external team but "owned" by the countries, which identified gaps and developed plans for improving preparedness. The assessment tool and procedure became more sophisticated as national and local pandemic preparedness became more complex. The 2009 pandemic revealed new gaps in planning, surveillance communications and immunization. LESSONS LEARNT: Structured national self-assessments with support from external teams allow individual countries to identify gaps in their pandemic preparedness plans and enable regional bodies to assess the regional and global resources that such plans require. The 2009 pandemic revealed additional problems with surveillance, pandemic severity estimates, the flexibility of the response, vaccination, involvement of health-care workers and communication. European national plans are being upgraded and global leadership is required to ensure that these plans are uniformly applied across the region.

The importance of influenza prevention for public health.

Annual epidemics of seasonal (inter-pandemic) influenza represent a significant burden on society in terms of morbidity, mortality, hospitalizations and lost working time. The impact of influenza depends on a mix of direct and indirect effects and is not easy to assess. Nevertheless there is a consensus in considering influenza prevention and mitigation high priorities for public health. We review the available evidence to assess the impact of influenza prevention focusing especially on vaccines and immunization strategies.

The use of masks and respirators to prevent transmission of influenza: a systematic review of the scientific evidence.

There are limited data on the use of masks and respirators to reduce transmission of influenza. A systematic review was undertaken to help inform pandemic influenza guidance in the United Kingdom. The initial review was performed in November 2009 and updated in June 2010 and January 2011. Inclusion criteria included randomised controlled trials and quasi-experimental and observational studies of humans published in English with an outcome of laboratory-confirmed or clinically-diagnosed influenza and other viral respiratory infections. There were 17 eligible studies. Six of eight randomised controlled trials found no significant differences between control and intervention groups (masks with or without hand hygiene; N95/P2 respirators). One household trial found that mask wearing coupled with hand sanitiser use reduced secondary transmission of upper respiratory infection/influenza-like illness/laboratory-confirmed influenza compared with education; hand sanitiser alone resulted in no reduction. One hospital-based trial found a lower rate of clinical respiratory illness associated with non-fit-tested N95 respirator use compared with medical masks. Eight of nine retrospective observational studies found that mask and/or respirator use was independently associated with a reduced risk of severe acute respiratory syndrome (SARS). Findings, however, may not be applicable to influenza and many studies were suboptimal. None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection. Some evidence suggests that mask use is best undertaken as part of a package of personal protection especially hand hygiene. The effectiveness of masks and respirators is likely linked to early, consistent and correct usage.

Factors associated with uptake of vaccination against pandemic influenza: a systematic review.

BACKGROUND: In June 2009 a global influenza pandemic was declared by the World Health Organisation. A vaccination programme against H1N1 influenza was introduced in many countries from September 2009, but there was low uptake in both the general population and health professionals in many, though not all, countries. PURPOSE: To examine the psychological and demographic factors associated with uptake of vaccination during the 2009 pandemic. METHOD: A systematic literature review searching Web of Science and PubMed databases up to 24 January 2011. RESULTS: 37 articles met the study inclusion criteria. Using the framework of Protection Motivation Theory the review found that both the degree of threat experienced in the 2009 pandemic influenza outbreak and perceptions of vaccination as an effective coping strategy were associated with stronger intentions and higher uptake of vaccination. Appraisal of threat resulted from both believing oneself to be at risk from developing H1N1 influenza and concern and worry about the disease. Appraisal of coping resulted from concerns about the safety of the vaccine and its side effects. There was evidence of an influence of social pressure in that people who thought that others wanted them to be vaccinated were more likely to do so and people getting their information about vaccination from official health sources being more likely to be vaccinated than those relying on unofficial sources. There was also a strong influence of past behaviour, with those having been vaccinated in the past against seasonal influenza being more likely to be vaccinated against pandemic influenza. Demographic factors associated with higher intentions and uptake of vaccination were: older age, male gender, being from an ethnic minority and, for health professionals, being a doctor. DISCUSSION: Interventions designed to increase vaccination rates could be developed and implemented in advance of a pandemic. Strategies to improve uptake of vaccination include interventions which highlight the risk posed by pandemic influenza while simultaneously offering tactics to ameliorate this risk (e.g. vaccination). Perceived concerns about vaccination can be tackled by reducing the omission bias (a perception that harm caused by action is worse than harm caused by inaction). In addition, interventions to increase seasonal influenza vaccination in advance of a future pandemic may be an effective strategy.

Seroprevalence to influenza A(H1N1) 2009 virus--where are we?

Age-specific seroprevalences for influenza virus make important contributions to estimating the burden of infection and determining the vulnerable populations. It is especially difficult to know the true clinical attack rates of the 2009 influenza A(H1N1) pandemic; however, we can estimate infection rates through analyses of seroprevalences based on national studies from different continents and countries with different demographics. After the 2009 influenza A(H1N1) pandemic, seroprevalence studies found 5 to 60% of populations across different continents and age groups having antibodies against the A(H1N1) 2009 virus. The seropositivity was highest in children and teenagers (20 to 60%) as well as in the elderly older than 80 years (20 to 40%). Preexisting cross-reactive antibodies against the virus were present mostly in sera of older people (born before 1950) who could have encountered viruses descended from the 1918 pandemic viruses. Experience with the 2009 pandemic indicates how essential early and timely serology data against the emerging virus can be for informing decisions on use of antivirals and vaccination campaigns, especially in regard to risk groups. The objectives of this review were to summarize the current data available on seroprevalence before and after the 2009 influenza A(H1N1) pandemic and the lessons learned for future pandemic preparedness.

The epidemiology of progressive intellectual and neurological deterioration in childhood.

OBJECTIVE: To study the epidemiology of diseases that cause progressive intellectual and neurological deterioration (PIND) in UK children. DESIGN: Since May 1997, the authors have performed active surveillance to search for variant Creutzfeldt-Jakob Disease (vCJD) among the many diseases that cause neurological deterioration in children, using the monthly surveillance card sent to all UK consultant paediatricians by the British Paediatric Surveillance Unit. The authors obtain clinical details from reporting paediatricians by questionnaire or site visit, and an Expert Group then independently classifies the cases. RESULTS: After 12 years, 2636 patients less than 16 years old with suspected PIND had been reported, of whom 1114 had a confirmed diagnosis to explain their deterioration: in these children, there were 147 different diseases. These were the six commonest diagnostic groups: leukoencephalopathies (183 cases), neuronal ceroid lipofuscinoses (141 cases), mitochondrial diseases (122 cases), mucopolysaccharidoses (102 cases), gangliosidoses (100 cases) and peroxisomal disorders (69 cases). Relatively large numbers of PIND children were reported from parts of the UK where there are high rates of consanguinity. Only six children with vCJD (four definite, two probable) had been identified. CONCLUSIONS: Although this study does not ascertain all UK cases, it provides a novel insight into the epidemiology of the neurodegenerative diseases that cause PIND in children. It is reassuring that in general these children are carefully investigated and that active surveillance has found only six children with vCJD. However, there is concern that more childhood vCJD cases may appear, possibly with a different genotype from those identified so far.

Seasonal and pandemic influenza vaccines for the elderly and other risk groups: a review of available data.

Human seasonal influenza is a large burden of morbidity and mortality for societies, affecting mainly elderly people and those with underlying chronic medical conditions. Annual vaccination of older adults and other risk groups is the most effective measure for reducing morbidity and mortality associated with infection. A 2008 survey showed 40-fold differences between the vaccination coverage in various European Union countries in individuals aged >or=65 years, ranging from less that 2% to more than 80% in the 2006-2007 season, with Poland belonging to the countries with low influenza vaccination coverage. Annual monitoring of the vaccination coverage is crucial for achieving and maintaining high uptake levels. The need to pay for the vaccine out of pocket is a strong factor discouraging vaccination, and there is evidence that reimbursing costs of influenza vaccination influences vaccination coverage. Although annual influenza immunization of healthcare workers is an important method of preventing the nosocomial transmission of influenza and decreasing the exposure of vulnerable patients, worldwide influenza vaccination rates among healthcare personnel are unacceptably low, rarely exceeding 40%. It is important to keep high vaccination coverage among elderly nursing-home residents. More research is needed to clearly establish the effect of dose sparing strategies of influenza vaccination, e.g., via intradermal immunization, on the immune response in elderly recipients. Finally, due to the emergence of the pandemic influenza A (H1N1) 2009 virus and the development of vaccines directed towards it, the upcoming influenza season 2009-2010 will pose a particular challenge to influenza vaccination programs, and will require careful planning.

Closure of schools during an influenza pandemic.

In response to WHO raising the influenza pandemic alert level from phase five to phase six, health officials around the world are carefully reviewing pandemic mitigation protocols. School closure (also called class dismissal in North America) is a non-pharmaceutical intervention that is commonly suggested for mitigating influenza pandemics. Health officials taking the decision to close schools must weigh the potential health benefits of reducing transmission and thus case numbers against high economic and social costs, difficult ethical issues, and the possible disruption of key services such as health care. Also, if schools are expected to close as a deliberate policy option, or just because of high levels of staff absenteeism, it is important to plan to mitigate the negative features of closure. In this context, there is still debate about if, when, and how school closure policy should be used. In this Review, we take a multidisciplinary and holistic perspective and review the multiple aspects of school closure as a public health policy. Implications for the mitigation of the swine-origin influenza A H1N1 pandemic are also discussed.