Q&A: The basics of flu shots

Some basic questions and answers to know in preparation for flu season:

Why should I bother to get a flu shot?

The flu kills anywhere from 10,000 to 50,000 people a year, mostly those over 65, under 2 or who have weakened immune systems. But the flu is also unpredictable and can cause severe illness even in healthy people, said Tom Frieden, director of the Centers for Disease Control and Prevention. Last year, Frieden said, a young woman in his office caught the flu and told him she was terrified she was dying. “Flu is serious. Flu is unpredictable. Flu often gets not enough respect,” he said in a Thursday morning news conference. To prevent widespread infections and provide what’s called herd immunity, about 70% of the American public needs to get vaccinated, according to CDC targets.

Can you get the flu from the flu vaccine?

No. It’s impossible to catch the flu from the vaccine, because there is only dead virus in the shot. The nasal spray vaccine did contain live virus, but is not available this year. People may mistake side effects of the vaccine – muscle aches and low fever – for the flu itself, said Nicole Bouvier, an infectious disease physician and researcher at Mt. Sinai Hospital in New York City. Or they may coincidentally be exposed to the flu shortly before or after vaccination, which can take weeks to become fully effective, said Shira Doron, an infectious disease physician at Tufts Medical Center, in Boston.

How do you know if you have the flu or a common cold? 

Generally, the flu comes on fast – “You feel like you got hit by a truck,” Doron said – while a cold comes on more slowly. A head cold is also more likely to cause sore throat and sinus issues, she said, while the flu triggers coughs, body aches and fever.

What should you do if you get the flu?

A flu vaccine may reduce the severity of infection and risk of hospitalization, even if you do get sick with the flu, research shows. Anti-viral medications can be effective at reducing flu symptoms, particularly if given early in the course of the illness, said William Schaffner, medical director of the National Foundation for Infectious Diseases. Obviously staying home and washing your hands frequently makes sense if you have a contagious illness like the flu.

Who should or shouldn’t get the flu shot?

Virtually everyone over 6 months of age should get a flu shot every year, Frieden said. Even people with egg allergies and previous reactions to the shot can probably get vaccinated again, unless their reaction was more severe than hives, Doron said. Anyone who had breathing problems, swollen, lips or tongue, light-headedness, recurrent vomiting, or epileptic seizures  after a previous vaccination should get the shot only in a supervised medical setting like a doctor’s office or hospital, she said.

Is the vaccine safe for pregnant women?

Yes, pregnant women should be vaccinated against the flu, Bouvier said. They are more vulnerable to flu, because the immune system is turned down during pregnancy. The flu poses a risk to the fetus, and women who get vaccinated during pregnancy seems to receive some protection against delivering early if they do get sick, she said.

How can I convince a co-worker to get vaccinated?

You can explain to your co-worker that even if they’re not particularly vulnerable to the flu, they might expose someone who is too young to be vaccinated or particularly susceptible because of age or immune weakness. 

There are several different types of vaccine on the market. Which one should I get?

The answer depends in part on your age. Health officials recommend that people over 65 get stronger version of the vaccine – either one with a high dose, or an adjuvant that amplifies its effect. Around age 65, most people’s immune system starts to work less efficiently and needs a more powerful vaccine, said Wilbur Chen, an associate professor at the University of Maryland School of Medicine. For younger people, there is a choice between a vaccine that protects against three strains of the virus and one that protects against four. Bouvier recommends the so-called quadrivalent vaccine because it offers broader protection, even though there is less long-term data on its safety and effectiveness. Mt. Sinai, where she works and gets her own vaccine, uses the quadrivalent kind. 

For people who are terrified of needles, the loss of the FluMist nasal vaccine is a blow. There are other options that don’t involve needles, including a jet injector system that your doctor’s office can order, or a system that involves a small needle that goes only as deep as the skin, not the muscle, Bouvier said.

When should I get my flu shot? 

The US Centers for Disease Control and Prevention recommends that everyone get vaccinated before the end of October. Although the vaccine’s effectiveness fades, most people will get a season’s worth of protection if they are vaccinated before Halloween, said CDC Director Frieden. Waiting longer to guarantee protection into the spring will make you vulnerable if the flu season arrives early. Bouvier said she’s already seen some cases of the flu at Mt. Sinai-affiliated hospitals in recent weeks, though it’s unclear whether those are outliers or signs of an early flu arrival.