About 10,000 Americans died in each of seven separate epidemics between 1977 and 1988, with 80 to 90 percent of those deaths occurring in individuals over the age of 65. Influenza is much like the common cold, with headache, runny nose, cough, fever and general weakness and malaise among the symptoms. However, the intensity and duration of these symptoms are more severe than the common cold, and they usually force infected individuals to take to their beds.
Influenza viruses change each year due to genetic mutation.
For this reason, an annual immunization with the latest version of the vaccine is recommended. Adverse reactions are usually mild, including soreness at the site of injection, muscle aches and a slight fever. However, because the vaccine is produced using hen's eggs, anyone with a known allergy or reaction to eggs or egg products should not receive this vaccine.