Flu season officially begins Friday, Oct. 1, and unlike last years season when shortages lead to rationing, there will be plenty of vaccine on hand for everyone who wants a flu shot.
"There are seven companies making flu vaccine this year and more than 160 million doses are expected for the United States," says Dr. Michael Koller, associate professor at the Loyola University Chicago Stritch School of Medicine in Maywood, Ill. "Thats more than ever."
Every flu season is different and there is no way to know in advance how mild or serious any particular season will be, Koller says. "You learn lessons from past seasons but you always have to have a healthy respect for the flu because in one weeks time, the situation can change dramatically for the worse."
This season the H1N1 strain, also known as "swine flu," is still around but its not as widespread. To account for its presence, this years flu vaccine will contain the H1N1 strain as well as two others the Perth H3N2 virus and the B Brisbane virus. "So only one vaccine is required, unlike the two that were recommended last year," Koller says.
Also, a new high-dose vaccine is available for people ages 65 and older, Koller says. The vaccine for seniors contains four times the amount of flu antigen (the active ingredient) as the standard flu shot. "An older persons immune system is not as robust as a younger persons, so when seniors get a standard flu shot, they dont generate as great an immune response," Koller says. "The immune response is what protects everybody two weeks after they are vaccinated."
Also, because flu vaccine supplies are plentiful, the Centers for Disease Control (CDC) recommends universal vaccination for all people ages 6 months and older this year. Health-care workers and those caring for people in an at-risk group should also be vaccinated, since a person can be infected and contagious for a short period of time before coming down with the classic symptoms of the flu.
The flu is a highly contagious viral infection that attacks the respiratory system. Doctors used to advise getting a flu shot only in October and November. Now doctors vaccinate through February because it takes about two weeks to develop an antibody response after the flu shot. For the last 30 years in the United States, February has been the peak month for illness, though infections can occur through April.
"Flu is primarily spread by respiratory droplets," Koller says. "When somebody with influenza coughs or sneezes, out shoots this spray of flu virus that can infect anyone nearby. In addition to covering your mouth when you cough and covering your nose when you sneeze, its really important to wash your hands to decrease the spread of the flu."
Each year in the U.S. between 5 and 20 percent of the population contracts the flu. Symptoms include an abrupt onset of fever, chills, headaches, exhaustion, aching muscles and a constant, unproductive cough, Koller says.
Most people recover from the flu in a few days, although they may experience some fatigue for several weeks after, Koller said. However, for some people flu is a much more serious illness that requires hospitalization. In extreme cases, the flu can lead to pneumonia or death. About 36,000 Americans die and 200,000 are hospitalized from the flu each year.
"Once you have the flu, you never forget it," Koller says. "Usually those are the people you dont have to convince to get a flu shot because they never want to get it again."
Koller said that its impossible to get the flu from getting a flu shot, which is a common misperception. However, he added that some would experience some side effects.
"Some people get soreness or pain at the site of the injection. A smaller number of people will feel achy and tired," Koller says. "But all of those side effects are usually gone after two days. If its the first year that youve gotten the flu shot, youre more likely to get the side effects. In the subsequent years, youre much less likely to get them."