Understanding the Flu Vaccine

Do you have chills, body aches, fever, sore throat, headache and watery eyes? You just might have the flu. The flu season normally runs from January to March, but it can vary by year and geographical area. “It’s generally a three-month season. In a specific community, the season lasts about six to eight weeks when it hits,” says James Wilde, M.D., an emergency physician at the MCGHealth Children’s Medical Center, associate professor of emergency medicine at the Medical College of Georgia and a member of the Georgia Pandemic Flu Committee and the MCG Pandemic Flu Committee. “[The flu] arrives, flares up like a Roman candle and quickly burns out,” he adds. Unlike most other contagious illnesses, flu spreads rapidly from person to person and has a very short incubation period. “This is the recipe for explosive epidemic,” says Dr. Wilde.

This partially explains why the 2009 swine flu outbreak drew so much concern from the medical community. An additional justification for the worldwide alarm is that, opposite of typical flu strains, the H1N1 swine flu impacted children and young adults the greatest, resulting in approximately 12,000 deaths. Older adults appear to have some natural immunity and are less likely to become infected with 2009 H1N1 swine.

Because H1N1 swine didn’t manifest until after the 2009-2010 flu vaccine had been developed, a second vaccine specifically targeting it was formulated and given in addition to the regular annual flu shot. In February each year, the World Health Organization (WHO), based on epidemiologic data gathered globally, predicts which flu strains will pose the most threat to public health in the next flu season. This may seem rather far in advance, but even beginning in February the timeline for naming the targeted strains to mass production is short. As soon as the announcement is made, labs begin developing the vaccine so that the FDA can approve it by spring. Manufacturing begins by August with a goal of having vaccines available for distribution by October. The 2010-2011 vaccine includes the 2009 H1N1 swine plus an H3N2 virus and an influenza B virus.

First created in the 1940s by a team of scientists that included Jonas Salk, who later developed the polio vaccine, the flu vaccine is the only vaccination that is continually updated. Dr. Wilde says, “Flu is constantly evolving and it’s hard to stay ahead of it all the time.” The goal of the flu vaccine is to prime the immune system to recognize particular strains of flu virus and build antibodies to fight them off. Because of antigenic drift, however, the proteins on the virus change slightly year to year so that last year’s vaccine is no longer effective this year. “What we told the immune system to look at last year is not the same as this year so the immune system doesn’t recognize it and respond,” explains Dr. Wilde.

Even with the flu vaccination designed yearly to pinpoint particular flu varieties and made widely available to the American public, 36,000 people per year die from complications due to the flu. The Centers for Disease Control (CDC) and the WHO have responded by recommending that everyone over the age of six months receive the flu vaccination. Children under eight years who have never been vaccinated should receive two vaccinations about four weeks apart, beginning in October, to gain full effectiveness.

In the past people over 65 were called to do the same. Traditionally, the flu shot, while about 90 percent protective for healthy adolescents and adults, is only about 50 percent protective for senior citizens. FluZone High Dose, available for the first time this year, is formulated to increase antibody response, thus improving the protective value of the vaccination; therefore eliminating the need for a second shot. For everyone else, the flu shot, whether administered when first available or later, remains effective for the entire flu season.

Despite the CDC and WHO urging people to get vaccinated, and the array of sites other than doctors’ offices and health departments now approved for administering flu shots, a policy change Dr. Wilde views as beneficial, not everyone will do so. Some people remember the swine flu vaccination pushed through development in 1976 to combat what the Ford administration feared was a pending pandemic. Unfortunately, as a side effect of the vaccination, several hundred people (a relatively small number compared to the number who received the vaccination) developed Guillain-Barre syndrome, an illness progressively affecting peripheral nerves causing symmetrical weakness and paralysis. “Because of this,” says Dr. Wilde, “people erroneously believe the flu vaccine is dangerous. People feared the 2009 swine flu vaccine, but there were no significant problems.”

Another argument posed against the flu vaccine is related to the diminished protection it provides after age 65. Some scientists believe it might make more sense to go ahead and contract the flu while young and build antibodies so that when a person reaches age 65 and older, when the potential for complications due to flu increases significantly, the vaccine can aid the body’s natural resistance. Furthermore, with no vaccine, a person only risks getting the flu once every 10-20 years. Should the young and healthy get vaccinated year after year to avoid one or two five-day bouts of the flu?

Finally, there are those who believe the vaccination itself results in flu illness. “The flu vaccine cannot give you the flu. It is not possible to get the flu from the flu shot,” emphasizes Dr. Wilde. The flu vaccine is made using killed virus. It takes about two weeks from getting the vaccination for a sufficient number of antibodies to build up. Some people who get the flu shot have either already been exposed to the flu virus or are exposed shortly after getting the vaccine and incorrectly attribute the illness to the shot.

It is important to note here that FluMist, a flu vaccine containing the same components as the shot but administered nasally, works somewhat differently from the shot. It contains live, but highly weakened virus, which actually does give the recipient a very mild, but not contagious, case of the flu. In response, the body builds antibodies. Dr. Wilde says, “Some studies show it has better protection than the shot.” Nonetheless, because of the live virus, only healthy people ages two to 49 can get the FluMist vaccine. “In that age group I recommend the FluMist,” he says, also noting, however, that only about five percent of vaccines manufactured are FluMist. The rest are shots.

Representatives from the CDC and WHO counter that the vaccine doesn’t just protect the individual, it protects the people with whom that individual comes into contact. Although Dr. Wilde says, “I don’t think it’s essential for young healthy people to get the flu shot,” he is adamant that 100 percent of healthcare professionals should be vaccinated, as well as children under the age of two and any person who lives with or comes into contact with someone who has a high-risk medical condition. He also says, “No one is opposed to the elderly and people in high-risk medical situations getting vaccinated.”

What to do if you have the flu? Stay home advises Dr. Wilde. Only people with high-risk medical conditions should see a doctor for the flu. Overuse of anti-virals, such as Tamiflu, can result in flu viruses becoming resistant to the treatment, which means they are ineffective in cases in which the need is great. “The public needs to understand,” says Dr. Wilde, “that even in best case circumstances, these medications are not very effective.” He adds, “Antibiotics are completely worthless against the flu. They have no effect on the flu.” So if you have chills, body aches, fever, sore throat, headache and watery eyes, stay home, drink lots of fluids and get plenty of rest. If you don’t have these symptoms, you might consider getting your flu shot.