Flu Shot 101: Let’s Discuss Facts and Myths

It’s still not too late to get a flu shot. In fact, it may save your life.

This is the first year the Centers for Disease Control map of flu activity is all the same color in the continental United States – red, meaning widespread.

Also of note: officials had originally expected flu activity to peak by mid-January. Instead, it continued to increase as of January 13, according to the latest CDC report, promising to be one of the busiest flu seasons in a decade.

The flu shot is the best mechanism we have to prevent influenza, according to Dr. Robert Duncan, an infectious disease specialist at Lahey Hospital & Medical Center.

Dr. Duncan explained the flu shot and highlighted its importance.

Some reports are saying the flu shot is only 10 percent effective this year. Is this true, or is there more of a range?

RD: Nobody yet knows what the effectiveness is. The 10 percent figure was based on one of the four flu strains they found in Australia. The Southern Hemisphere flu season typically precedes what we get in the Northern Hemisphere. The shot’s efficacy last year in the US was about 34 percent and many think this year’s vaccine will be in the same range. Being 1/3 less likely to get the flu is pretty important.

Can you catch the flu because of the vaccine (a common myth)? Is there any truth to that?

RD: The virus in the vaccine is killed, so the vaccine cannot cause flu. Some people may catch the flu after getting the vaccine but not because of the vaccine.

Are there other benefits to getting the flu shot, even if it’s not 100 percent effective?

RD: Many think of the flu as just an inconvenience, but it’s a dangerous disease that can precipitate heart attacks or strokes. Every year we see people who end up on a ventilator, on dialysis, or die. But even when the shot doesn’t prevent the disease completely, it decreases the big complications significantly.

Severe complications usually occur in the old and young, but also in pregnant women. When they get the flu it can progress to pneumonia, which can be deadly. It can also cause miscarriage. It’s important to note that the vaccine protects the baby for 6 months after birth, reducing the need for hospital admission by 90 percent. The shot is entirely safe for mother and child and it provides life-saving benefits for both.

Is there ever a point in the season when it’s too late to get the flu shot?

RD: There is a saying: the flu is predictably unpredictable. Flu season generally runs December to May. Some years it will peak early, some late. The H1N1in 2009 – commonly referred to as swine flu – had two peaks. It’s hard to predict. This season started early and my guess is that it will go away sooner than some of the flu seasons but it’s also a busier season and hasn’t slowed yet. The CDC recommends giving the shot between September and mid-November but if you missed the window, throughout the flu season.

If one is allergic to eggs, does he or she have to worry about getting the shot?

RD: The vaccine is currently produced in eggs, but there is a tiny amount of egg protein left after purification. Recent studies show that flu vaccine can be given safely to people with egg allergies. The CDC says there are no special considerations needed for those with egg allergies. But a concerned patient can go to an allergist to get the shot in a monitored environment.

At what age should children start getting flu shots?

RD: About six months, and particularly for kids in day care. They’re often the ones who bring home the flu and give it to everyone else.

For more information throughout this flu season, visit our online flu center.


*The content on this website is for informational purposes only and is not medical advice. Please consult a physician regarding your specific medical condition, diagnosis and/or treatment.

MORE IN Live Well