The next influenza epidemic
If you haven't thought about a ‘flu' epidemic consider these two recent quotes: "No country is fully prepared for a 1918-like pandemic influenza. Averting a pandemic of H5N1 influenza virus depends on the successful control of its endemicity, outbreaks in poultry and occasional spillage into human which carries a case-fatality rate of over 50%." (Guan Y, BMC Infect Dis. 2007 Nov 13;7(1):132.)
"If an influenza pandemic occurs, it is expected to have dire consequences, including millions of deaths, social disruption, and enormous economic consequences. The Department of Health and Human Resources plan, released in November 2005, clearly affirms the threat of a pandemic." (Mody L, Cinti S. J Am Geriatr Soc. 2007 Sep;55(9):1431-7.)
I have looked a bit further into the question of a new outbreak of influenza and want to share some of what I have found.
During the period from May 20 to September 15, 2007, WHO and NREVSS collaborating laboratories in the United States tested 21,029 respiratory specimens for influenza viruses; 398 (1.9%) were positive. Of these, 330 (83%) were influenza A viruses, and 68 (17%) were influenza B viruses. Of the influenza A viruses, 152 were subtyped: 67 (44%) were influenza A (H1) viruses, and 85 (56%) were influenza A (H3) viruses. Influenza viruses were reported from 22 states in eight of the nine public health surveillance regions. However, 200 (50%) of all the influenza viruses, including 63 (94%) of the 67 influenza A (H1) viruses, were reported from Hawaii, and 100 (25%) were reported from Florida.
Migratory birds and, less likely, bird trafficking are believed to be extending the avian influenza A/H5N1 globally. More than 200 human cases of avian influenza virus infection due to A/H5, A/H7, and A/H9 subtypes mainly as a result of poultry-to-human transmission have been reported with a greater than 50% case fatality rate for A/H5N1 infections. A mutant virus capable of efficient human-to-human transmission could trigger another influenza pandemic.
There does seem to be a question of how these viruses are transmitted. From 21 March through 3 April 2006, 295 poultry workers and 25 laboratory workers with suspected exposure to H5N1 virus were administered a questionnaire to assess H5N1 exposures, medical history, and health care utilization. A serum specimen was collected from participants to test for H5N1 neutralizing antibodies by microneutralization assay. The 295 poultry workers reported a median of 14 days of exposure to suspected or confirmed H5N1-infected poultry without antiviral chemoprophylaxis and with minimal personal protective equipment. Among 25 laboratory workers, all handled poultry specimens with suspected H5N1 virus infection. All participants tested negative for H5N1 neutralizing antibodies.
Relating to the transmission of avian virus to human a study to assess the molecular characterization of H5N1 viruses from Thailand showed that there were no significant point mutations in the critical regions, and there was no evidence of changes in the viruses that indicate they are capable of sustained human-to-human transmission.
How to prevent an outbreak has also been the subject of some discussion. Increased attention to prophylaxis against viral infection has identified several potentially complementary approaches: nonpharmacologic measures (e.g., travel restrictions), vaccination, chemotherapeutic agents, and herbal/natural products. All have significant limitations that point out the need for additional. Herbal/natural products, particularly those based on green tea extract, offer promise as adjuncts or alternatives to current interventions and warrant further evaluation in well-controlled human trials.
Should an outbreak occur it is expected to have dire consequences, including millions of deaths, social disruption, and enormous economic consequences. The Department of Health and Human Resources plan, released in November 2005, clearly affirms the threat of a pandemic. Anticipating a disruption in many factions of society, every segment of the healthcare industry, including nursing homes, will be affected and will need to be self-sufficient. Disruption of vaccine distribution during the seasonal influenza vaccine shortage during the 2004/05 influenza season is but one example of erratic emergency planning. I can confirm a shortage of ‘flu shots' in my area in November-December 2007.
I'd be interested in having some of your comments on your own institution's preparations for an influx of ‘flu' patients, what the community's thoughts are on making plans and your own thoughts on the issues surrounding a possible if not inevitable epidemic.