Flu Shots: Debunking 5 Popular Myths about the Flu Vaccine

By Dr. Christopher Harrison, Division of Infectious Diseases

The first cases of true influenza have been reported. Again we’re expecting at least a moderately severe flu season nationally this year. To put it in perspective, one in every three unvaccinated children is predicted to get influenza, while one in nine unvaccinated adults will get symptomatic influenza.

The best available way to protect yourself and your loved ones is the flu vaccine. Vaccine can reduce illness severity, and/or the number of flu illnesses, trips to the doctor, missed days at school and work, and flu-related deaths in children.

People with excuses why they don’t “want” or “need” flu vaccine should reconsider.

Excuse #1 “I don’t get the flu.”

In the average season, influenza disease affects 5–15 percent of adults and 20–30 percent of children both globally and in the United States. Attack rates are higher in seasons with antigenic shift (possible this year) or a pandemic strain, but lower in seasons when influenza strains change little from prior seasons. Based on changes in 2019-20 vaccine strains, there will likely be changes in circulating strains, so we expect higher than average attack rates, particularly for the H3N2 virus.

Excuse #2 “The influenza vaccine doesn’t work.”

The influenza vaccine effectiveness varies from year-to-year and is anywhere between 30-80 percent depending on factors such as season (do circulating strains match vaccine strains), age (youngest and oldest are less-well protected), and which subtype predominates (H3N2 worse in older adults and H1N1 worse in children). While the flu shot may not be as effective as other vaccines, if the entire eligible US population (estimated 300 million) was flu immunized, there could be 100 million fewer influenza illnesses even in a suboptimal vaccine effectiveness year.

Excuse #3 “The flu shot makes me sick.”

Injectable inactivated influenza vaccines (the shots) cannot cause influenza infection. “Inactivated” means that there are no living virus in the vaccine. Most patients readily tolerate the usual mild local pain, swelling and redness at injections sites. The systemic effects (mild headache, achiness or fatigue) are interpreted as “getting the flu,” but these symptoms are similar to those that the day after a hard workout and represent the hard work our immune systems do to produce protection.

Of note the intranasal flu vaccine drops are acceptable this year and do have a weakened live virus in it. Side effects are mostly a mild runny nose and perhaps low grade fever. For those with needle phobia – this could be an option. One caveat – while it is at least as effective as the shot against H3N2 and B strains, we are not sure how protective it is against the H1N1 flu.

Excuse #4 “I already had the flu earlier this year.”

People who say they already had the flu or as many put it “stomach flu,” haven’t had influenza. True influenza starts off with heavy duty muscle pain, sore throat, headache, eye pain, fatigue and cough that may last for two weeks.

And that’s simple influenza. Each year, 100-150 children die from the flu due to complications. Children, the elderly and pregnant women are at higher risk for complications, but anyone can have an influenza complication. Influenza vaccine is the best way to avoid influenza-related complications.

Excuse #5 “I have an egg allergy.”

The American Academy of Pediatrics’ recent policy states that physicians can administer egg-based influenza vaccine to children and teenagers with egg allergies without special precautions beyond those that apply to other vaccines. In addition there are “cell-based” vaccines that are made in test tubes not from eggs. They are approved for those >4 years old.

Summary: Flu activity in our region has already started and is expected to peak between December and February, so it’s not too late to receive your vaccination. You’ll want to get it sooner rather than later now that we are nearing Halloween, since it takes two weeks for the vaccine to build up immunity in an adult and it may take two doses at least 1 month apart to protect children <9 years old if they have not had two prior doses in their lifetime.

Watch our doctors debunk the Top 10 Myths About Vaccines

Learn more about staying healthy during flu season.

Learn more about the Division of Infectious Diseases at Children's Mercy.