Considerations to vaccination in influenza pandemia

Influenza, or flu, is one of the infectious diseases associated witha high burden of disease, owing to seasonal epidemics each year.It can also generate pandemics leading to a high degree of socialdisruption and substantial economic losses. The Spanish fl u pandemicof 1918 was responsible for some 40 to 50 million deathsworldwide. Given the imminence of a pandemic, most likely producedby the A/H5N1 strain, drafting preparedness plans for an infl uenzapandemic should be a priority in all countries. Epidemiologicalsurveillance and vaccine production are essential for the control ofinfl uenza and the prevention of its devastating effects. The globalproduction of vaccines to fi ght seasonal infl uenza is very limited.Some 300 million doses are currently produced worldwide, with thefull production cycle taking 6 to 9 months once the circulating viruses are identifi ed. In a pandemic, two doses of vaccine will be requiredto protect each individual; thus, it has been estimated that only about14% of the population would have access to a monovalent vaccinein the early months of a pandemic. National pandemic preparednessplans should clearly defi ne the high-risk populations that should begiven priority in vaccination. This should be done before the crisishits, not in the midst of it.