Influenza pandemic planning and the paediatrician

The Canadian Paediatric Society (CPS) was asked to participate in a meeting for Provincial, Territorial and Local Pandemic Influenza Planning organized by Health Canada on January 27 to 28, 2000 in Toronto. The meeting's proceedings have implications for paediatricians and committees within the CPS. In a pandemic, an estimated 9000 to 51,000 excess deaths from pneumonia and influenza may occur in Canada (unpublished data), compared with the 500 to 1500 deaths during the annual influenza season (1). The latter numbers may underestimate the true impact that influenza has on the Canadian population each year because deteriorating chronic conditions also contribute to annual mortality. In the Spanish influenza pandemic of 1918/19, 50,000 to 60,000 Canadians were among the estimated 20 million to 40 million individuals who died worldwide. Deaths occurred across Canada, with the first cases appearing in a military encampment at Niagara-on-the Lake, Ontario. Much can be learned about the pandemic from a review of local archives in many Canadian communities and discussions with survivors. For example, death from hemorrhagic viral pneumonia was rapid, occurring within one or two days of symptom onset. With such widespread illness and death in healthy young people, there was a significant impact on the community, and on surviving orphans, widows and widowers. Community newspapers published daily status reports. Dating back to the 1500s, there is evidence of widespread influenza disease occurring three or four times during each century. The outbreak of pandemic disease in 1918/19 was caused by an H1N1 strain of influenza A. Subsequently, a H2N2 strain in 1957 and a H3N2 strain in 1968 led to widespread disease worldwide. Such global epidemics or pandemics are caused by the sudden emergence of new influenza A subtypes with major changes in the hemagglutinin H and/or the neuraminidase surface proteins, known as antigenic shifts; the majority of the world's population does not have immunity to the new influenza subtypes. The reassortment of viral genomes that results in antigenic shifts occurs through the mixing of human influenza strains with either avian or swine influenza viruses. In the 1997 Hong Kong H5N1 avian influenza (‘bird 'flu’) outbreak, six of the 18 infected people, who were mostly young individuals, died. Fortunately, the H5N1 virus was not easily transmissible between humans, but anxiety was created over the possibility that that further genetic changes in the virus may result in increased transmissibility. To mitigate the possible emergence of a virus with pandemic potential, one million chickens living in close proximity to humans in the markets of Hong Kong were slaughtered to reduce the opportunity for further transmission to humans. The characteristics of a pandemic are listed in Table 1. The differences between ‘pandemic’ and ‘epidemic’ influenza disease are listed in Table 2. It is of particular note that the first wave of a pandemic infection may occur outside of the usual winter influenza season. Furthermore, type A virus is generally, but not always, more virulent than type B disease, and to date, has caused pandemic disease. It is projected that influenza disease would surface in Canada within three months of a pandemic that originated in Asia, with the peak impact occurring within five to six months. Air travel may decrease this timeframe. Second and third waves of infection are expected. Definition of an influenza pandemic A novel influenza virus exhibits an antigenic shift High population susceptibility worldwide Evidence of high person-to-person transmissibility Widespread illness in multiple geographic areas with unusually high rates of morbidity and mortality A novel influenza virus exhibits an antigenic shift High population susceptibility worldwide Evidence of high person-to-person transmissibility Widespread illness in multiple geographic areas with unusually high rates of morbidity and mortality Definition of an influenza pandemic A novel influenza virus exhibits an antigenic shift High population susceptibility worldwide Evidence of high person-to-person transmissibility Widespread illness in multiple geographic areas with unusually high rates of morbidity and mortality A novel influenza virus exhibits an antigenic shift High population susceptibility worldwide Evidence of high person-to-person transmissibility Widespread illness in multiple geographic areas with unusually high rates of morbidity and mortality Differences between ‘epidemic’ and ‘pandemic’ influenza Time for preparation may be reduced through anticipatory preparation of seed strains, availability of eggs or use of nonegg culture technology Differences between ‘epidemic’ and ‘pandemic’ influenza Time for preparation may be reduced through anticipatory preparation of seed strains, availability of eggs or use of nonegg culture technology It is now recognized that the age-specific hospitalization rate of children under five years of age during influenza epidemics is equal to that of the elderly population in annual influenza epidemics. While the highest mortality in the 1918/19 pandemic occurred in young adults, this pattern was not seen in other pandemics. Each year, the National Advisory Committee on Immunization (NACI) issues recommendations for immunization of high risk children, including “children who require additional visits to adjust their medication to control asthmatic symptoms” (2). The uptake of publicly funded influenza vaccine by young persons with chronic conditions is dismally low despite the facts that the vaccine is safe, free and effective. Studies are underway to determine whether routine immunization of children with a cold-adapted nasal vaccine that is easily administered would reduce community disease in people of all ages. While the greater routine use of influenza vaccine in children may be recommended in the future, large multicentre studies are needed to evaluate the associated benefits, risks and economic effects before such routine immunization is considered (3). It is not known where or when (ie, during which season or year) pandemic influenza disease will strike. Interpandemic periods have lasted for 11 to 39 years; it has now been 32 years since the last pandemic. The following five areas of pandemic influenza preparedness planning are necessary: surveillance for viral activity; use of antiviral agents and vaccine; health services; preparedness of emergency services; and communication. Such planning is now underway internationally, federally, provincially and locally. Among the many laboratories in the global influenza surveillance network, four are regional reference centres operating under the auspices of the World Health Organization and the Centers for Disease Control and Prevention, and are located in Tokyo, Japan, Sydney, Australia, London, England and Atlanta, USA. In Canada and elsewhere, selected isolates are typed and sequenced to identify structural changes. The vaccine strains recommended by the World Health Organization for the 2000/01 season contain an A/Moscow/10/99 (H3N2)-like virus, an A/New Caledonia/20/99 (H1N1)-like virus and a B/Beijing/184/93-like virus. Characteristics of vaccine and antiviral prophylaxis are included in Table 2. The need to procure Canadian supplies of influenza vaccine to meet needs, rather than fostering dependence on international suppliers and running the risk of a potential embargo at the time of an epidemic, is of the highest priority. Stockpiling antiviral prophylaxis is also under consideration by federal authorities. Clinical practice guidelines that address the needs of young and elderly patients in ambulatory, hospital and community settings are needed. Such guidelines need to consider the spectrum of disease (eg, age, severity) and the number of cases, regardless of whether a vaccine is available. Computerized modelling systems that allow a region to estimate the impact of disease under diverse variables are available from provincial authorities. In the absence of adequate supplies of vaccines, beds, ventilators, etc, the need to prioritize the care of specific patient groups, as well as options for health care provision in the home, must be anticipated. The responsibility that care providers will feel to their own families must also be considered. The development of these guidelines with public health leadership will include input that extends beyond the usual involvement of medical experts in the fields of infectious diseases, emergency care and chest medicine to include many other groups such as pharmacists, ethicists, home care providers, volunteer groups, service clubs, morticians and community religious leaders. Community emergency preparedness through emergency measures involving police, fire departments, ambulance services and other essential services is already a well developed part of Canada's system of public safety. Plans to address chemical spills, nuclear disasters, natural disasters, etc, can be broadened to manage an influenza pandemic. With many unknown variables at the onset of a pandemic, the need for sustained active review of the situation, including patient management and the availability of supplies, is expected. The local monitoring team will need to be aware of new external information and the local situation, and have the flexibility to manage change by seeking external advice when necessary. There is concern that the widespread contemporaneous effect of influenza will mean that each area will have to manage the situation on its own. A checklist of pandemic preparedness is outlined in Table 3. Paediatricians should be encouraged to show leadership and participate in local planning initiatives to alert colleagues and associates to the need to reflect on the pre-pandemic phase now and to take appropriate action. For example, good use of vaccines and laboratory services now and during the next season will find Canada better prepared to deal with a pandemic. Web sites that paediatricians can access to obtain up-to-date information about influenza are provided in Table 4. Pandemic preparedness checklist for paediatricians Be aware of potential widespread ‘novel’ virus infection Raise the issue of pandemic influenza preparedness with colleagues and associates Encourage regional public health and hospital pandemic planning Be prepared to create, and accept flexible and innovative health care delivery in a pandemic situation Receive annual influenza immunization, and show leadership by encouraging vaccination in other health care workers Generate lists of patients in high risk groups who require immunization Provide annual influenza immunization to patients in high risk groups and track personal rate of immunization in practice Provide pneumococcal vaccine to children in high risk groups Instruct patients about the use of nonemergency department care for nonlife-threatening illness after regular office hours Early in the epidemic, send nasopharyngeal (or throat) swabs from suspected influenza cases for confirmation and strain identification, and participate in public health sentinel surveillance Accurately record the cause of death to include suspected or confirmed influenza infection Stay up-to-date about influenza developments. Information may be obtained through the Internet (Table 4) Be aware of potential widespread ‘novel’ virus infection Raise the issue of pandemic influenza preparedness with colleagues and associates Encourage regional public health and hospital pandemic planning Be prepared to create, and accept flexible and innovative health care delivery in a pandemic situation Receive annual influenza immunization, and show leadership by encouraging vaccination in other health care workers Generate lists of patients in high risk groups who require immunization Provide annual influenza immunization to patients in high risk groups and track personal rate of immunization in practice Provide pneumococcal vaccine to children in high risk groups Instruct patients about the use of nonemergency department care for nonlife-threatening illness after regular office hours Early in the epidemic, send nasopharyngeal (or throat) swabs from suspected influenza cases for confirmation and strain identification, and participate in public health sentinel surveillance Accurately record the cause of death to include suspected or confirmed influenza infection Stay up-to-date about influenza developments. Information may be obtained through the Internet (Table 4) Pandemic preparedness checklist for paediatricians Be aware of potential widespread ‘novel’ virus infection Raise the issue of pandemic influenza preparedness with colleagues and associates Encourage regional public health and hospital pandemic planning Be prepared to create, and accept flexible and innovative health care delivery in a pandemic situation Receive annual influenza immunization, and show leadership by encouraging vaccination in other health care workers Generate lists of patients in high risk groups who require immunization Provide annual influenza immunization to patients in high risk groups and track personal rate of immunization in practice Provide pneumococcal vaccine to children in high risk groups Instruct patients about the use of nonemergency department care for nonlife-threatening illness after regular office hours Early in the epidemic, send nasopharyngeal (or throat) swabs from suspected influenza cases for confirmation and strain identification, and participate in public health sentinel surveillance Accurately record the cause of death to include suspected or confirmed influenza infection Stay up-to-date about influenza developments. Information may be obtained through the Internet (Table 4) Be aware of potential widespread ‘novel’ virus infection Raise the issue of pandemic influenza preparedness with colleagues and associates Encourage regional public health and hospital pandemic planning Be prepared to create, and accept flexible and innovative health care delivery in a pandemic situation Receive annual influenza immunization, and show leadership by encouraging vaccination in other health care workers Generate lists of patients in high risk groups who require immunization Provide annual influenza immunization to patients in high risk groups and track personal rate of immunization in practice Provide pneumococcal vaccine to children in high risk groups Instruct patients about the use of nonemergency department care for nonlife-threatening illness after regular office hours Early in the epidemic, send nasopharyngeal (or throat) swabs from suspected influenza cases for confirmation and strain identification, and participate in public health sentinel surveillance Accurately record the cause of death to include suspected or confirmed influenza infection Stay up-to-date about influenza developments. Information may be obtained through the Internet (Table 4) Influenza-related Internet web sites Courtesy of Drs Paul Munk and Theresa Tam Influenza-related Internet web sites Courtesy of Drs Paul Munk and Theresa Tam The committee structure of the CPS is ideally suited to preparedness planning at the federal level. The Infectious Diseases and Immunization Committee can provide advice about appropriate paediatric medical care. During upcoming annual meetings of the CPS each June, it may be prudent for all committees and sections to consider pandemic influenza preparedness and how they may contribute. The month of June 2001 is the target date for the completion of pandemic preparedness planning across Canada. The next influenza epidemic season will ideally provide a time to see how far along planning has advanced. The challenge is there to be met.

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