Vaccination is the wisest course

Dear Dr. Eva,

How bad is the flu going to be this year? Should I get vaccinated? Which is better, the shot or the nose spray? How well do they work to prevent infection? Can you get sick with the flu from taking the vaccine?


Dear MW,

I’ll answer your questions one at a time. First, let’s look at the size of the problem.

Flu vaccine prevents influenza, which is a viral infection of the lungs. Influenza, or “flu,” causes high fever (usually over 101), headache, tiredness, sore throat, dry cough, stuffy nose, and body aches. The term “flu” is often mistakenly used to describe other infections, like colds and gastroenteritis (wrongly called “stomach flu.”) Flu vaccine cannot prevent colds or diarrhea.

Flu is not a minor illness. Every year, 10-to-20% of all the people in the US are infected with flu, and more than 200,000 people are hospitalized because of flu. According to the CDC, 36,000 Americans die of flu every year. Complications of flu include pneumonia, dehydration, and worsening of chronic medical conditions like congestive heart failure, asthma, and diabetes.

How bad is the flu going to be this year?

There’s no way to tell for certain how bad this year’s flu season will be. Every year, epidemiologists use information from flu outbreaks in the Southern hemisphere to estimate how bad the flu season will be in our Northern hemisphere, and to predict which strains of flu virus will cause the most sickness.

Should I get vaccinated?

You probably should! Your age, health, and job affect how important it is for you to get the flu vaccine. Some groups of people are more likely to catch the flu and are also more likely to get seriously ill or even die if they do get the flu.

You definitely should get flu vaccine if:

• You smoke

• You have chronic medical problems, especially lung problems such as asthma, heart disease, or problems that affect the immune system, such as diabetes and HIV

• You are over age 50 (this has changed, the old recommendation was over age 65)

• You work or live with people in any of these groups.

Flu vaccine is also recommended for all children from 6 months to 18 years old.

Which is better, the shot or the nose spray vaccine?

Flu vaccine can be given as either a shot or a nasal spray. There are 5 different brands of flu shots: all have very similar ingredients and work equally well. The nose spray (brand name FluMist) is only approved for people under 50 years old. The cost of the nose spray and the shot are about the same, about $30-35 at a doctor’s office, usually less at a pharmacy.

The shot is made from the outer coat of the virus. Contact with these parts of the virus gets the immune system ready to recognize and fight off the flu. Unlike the nose spray, the shot contains no live virus. The nose spray contains a mild “domesticated” version of live flu virus. Contact with this virus teaches the immune system to recognize and fight off flu. Both the shot and the nose spray vaccines protect against the three strains of flu virus expected to be most common this year. Research so far suggests that the nose spray may be more effective for kids and the shots more effective for adults.

How well does the vaccine work to prevent flu?

How well the vaccine works depends on your age and health. It also depends on the accuracy of this year’s prediction of which flu strains will be commonest. For healthy adults under age 65, the vaccine prevents infection in 80% of cases when the prediction is accurate and in 50% of cases when the prediction is wrong. It is less effective for older people and people in poor health. There are benefits of vaccination even when it does not completely prevent infection: when people who have been vaccinated get the flu, the sickness is milder. They are less sick, less likely to be hospitalized, and less likely to die than people who were not vaccinated.

Can you get sick with the flu from taking the vaccine?

No. I know what people say… Some of my own patients swear they have gotten sick from the flu shot and refuse to ever take it again, no matter how I try to explain.

Since there is no live flu virus in the injectable vaccine, it is not possible to get infected with the flu from a flu shot. But – other things can make it seem as if that’s what happens. Because it takes two weeks or longer for the flu vaccine to take effect, if a person is exposed to flu before getting the shot or within two weeks after getting it, they can get the flu because they weren’t protected yet when they were exposed. Or, the person may have gotten a cold or a stomach virus and be confusing that with the flu.

The nasal spray does contain a live virus, which can cause runny and stuffy nose and mild sore throat. As anyone who has had a real influenza infection can tell you, this is much milder than getting the flu.

You have a lot to gain and nothing to lose. Go get your flu shot now so it will be working by the time flu season really starts.

Eva Hersh is a Baltimore family physician. Send your comments and questions to her by email at

Author Profile

Dr. Eva Hersh, MD
Dr. Eva Hersh, MD
Eva Hersh is a family physician. Send your comments and questions to her by email at