Page 1 Using the Haddon Matrix to develop a general practice conceptual framework for pandemic planning Lyn Clearihan , George Somers, Eastern Ranges Division of General Practice Introduction By its nature, a pandemic is a catastrophe, disrupting the structure and function of any community engulfed by it. 1 Given our experiences with the influenza pandemics of 1918, 1957 and 1968, how ready is the world for another one? According to the World Health Organization’s (WHO) updated Influenza Preparedness plan,—not very; in spite of the fact that “ominous changes have been observed in the epidemiology of the disease in animals”. 2 Antigenic shift of the H5N1 Influenza A virus is currently regarded as the likely source of the next influenza pandemic. 3 This highly pathogenic viral subtype was isolated as the cause of the Hong Kong influenza epidemic in 1997, and in spite of that country’s massive culling of its poultry at the time 4 the H5N1 appears to be “expanding its host and geographic range”. 5 Since 2003, 49 countries have had confirmed cases of H5N1 in their bird populations with viral isolation from other mammalian species. 6 As of the 16th of October 2006 there have been 256 confirmed human cases with 151 deaths, spread across ten countries. 7 Human to human transmission is now presumed to have occurred between close contacts and WHO have warned that the threat posed is very real and likely to escalate with time due to the endemic nature of the H5N1 in poultry and the fact that domestic ducks can excrete large amounts of the virus without showing signs of illness 2 , thus increasing the risk of transmissibility to humans. While evidence of the human pathogenicity of the Influenza A viruses is well established 8 their behaviour is unpredictable. The degree of warning of an impending pandemic depends on whether the viruses antigenic shift results from a reassortment event, which could produce a sudden appearance of “cases with explosive spread”; or an adaptive mutation, which tends to occur in cluster outbreaks and may ‘buy time’ for containment measures and vaccination programs to limit global reach and impact. 2 For the Asia–Pacific region there is heightened concern as the majority of confirmed deaths from Avian Influenza are from this area, with over a third of those from Indonesia. Based on experiences from previous epidemics 9 an Australian estimate that uses a 25% strike rate, suggests that an influenza pandemic could produce 2.5–7.5 million ‘outpatient’ visits with a potential mortality rate of 13 000– 44 000 people. 10,11 This surge in demand is likely to quickly overwhelm all available health resources. Within Australia there has been both a national and a state based response to the need for pandemic planning. 10,12,13 Recognition of the place of general practice within the health sector response has however, been slow 14 with State based communications centring on case identification procedures 15 rather than point-of-care issues that are likely to engulf GPs. In reviewing the pandemic plans of nine countries in the Asia–Pacific area, of which Australia was one, Cokier and Mounier-Jack identified a number of generic weaknesses 5 pertinent for general practice: • “Operational responsibility remained somewhat unclear, especially at the local level.” • “Most did not detail drug strategies or logistics for provision for antiviral drugs to the population…they did not clearly specify treatment or use of prophylactics.” • “Most had poorly developed policies for vaccination of the population.” • “Most relied on health care institutions for the treatment of influenza patients (notably special infectious diseases hospitals). Some designated specific facilities as hospitals for infectious diseases. Few developed the possibility of caring for patients at home.” • “Many did not make adequate provision for the maintenance of essential services”.