Optimizing Barrier Protection During a
Pandemic Event Caused by Influenza A

Lessons Learned According to the WHO, there were 12 lessons learned from the last three pandemics vital for preparedness planning: Unpredictable viruses cause pandemics. Mortality, severity of the illness, and the pattern of spread have all varied. There is only one consistent feature in all of the viruses: The viruses are known to spread rapidly.We cannot know the severity of the illness in advance or the impact on healthcare workers. However, we do know that a sharp increase for medical assistance will always occur. The viruses have the capacity to be lethal in non-traditional age groups, mostly young adults. Mild pandemics are distinguished by severe deaths at the limits of the lifespan (the very young and the very old). The epidemiological potential for a virus has a propensity to develop in waves. At first, one age group might only be affected, but a more severe illness might occur later as a second wave. In 1918, the virus mutated within a few short months. Children that attended school were the primary vectors for the spread of the disease in the first wave. The second wave affected the elderly, who are more susceptible to severe disease and fatal complications. Virological surveillance has been an important tool in rapidly confirming the onset of pandemics, alerting health services, isolating and characterizing the virus, and making it available to vaccine manufacturers. Over the centuries, most of the pandemics have originated in parts of Asia, where dense populations of humans live in close proximity to ducks and pigs. Therefore, surveillance for both animal influenza and clusters of unusual respiratory illnesses in humans is an important early warning function. It has never been possible to completely stop pandemics from spreading internationally, but some public health interventions used in the past have delayed them. Quarantines and travel restrictions have shown little effect. Avoidance of travel to and from countries that have been associated with close contact and overcrowding, the temporary banning of public gatherings, and closures of schools are potentially effective measures. Impedance of the spread of the disease is advantageous. Decreasing the number of people who have the disease at one time increases the likelihood that medical and other essential services can be maintained, and helps prevent a sharp increase in the demand for healthcare. The impact of vaccines on a pandemic has not been confirmed. In the situations of 1957 and 1968, vaccine manufacturers responded rapidly, but inadequate production capacity resulted in the arrival of limited quantities too late to have an effect. Countries with domestic manufacturing capacity will be the first to receive the vaccines. The tendency of pandemics to be most severe in the later waves may extend the time before large supplies of vaccine are needed to prevent severe disease in highrisk populations. The intervals between successive waves may, however, be as short as a month. In the best-case scenario, mortality in a pandemic situation will hopefully reflect seasonal epidemic years that affect the extremes of the lifespan, therefore enabling countries that have adequate vaccination programs to protect those at risk. Even though this strategy can reduce excess mortality, sudden, large increases in morbidity and a corresponding high demand for medical care should be anticipated.48

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