Wavering about getting a flu shot? Get the facts

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Google, “Should I get the flu shot?” and get gigabytes of pro and con information. Bottom line: A yearly vaccination is still the best defense unless you are severely allergic to the vaccine.

Our medical research librarian investigated online for you! Here are some key facts and reasons why the vaccine is your best defense, based on major respected, non-biased health care studies and other trusted sources.

Interesting flu facts

  • You can spread the virus up to a day before you have symptoms!
  • You are most infectious three to four days after symptoms begin.
  • Young and those with weak immune systems can spread it longer.
  • Because the flu bug is a virus, antibiotics won’t help. 

Even more surprising

You can spread the flu even if you are not sick. A vaccine can prevent that. If you are exposed to the virus, the flu shot kills the particles when they enter your system.

Here’s an example: You sneeze into your sleeve. (Good move!) You haven’t been vaccinated, but luckily, you’re not sick so it shouldn’t be a problem. You then reach down to pick up your child, who snuggles against your coat sleeve or puts his fingers in his mouth. Your child might get the flu because your droplets may contain flu particles, since you weren’t vaccinated. 

How long does the flu bug live?
The flu is not an airborne virus. It’s spread through particles in droplets that can live up to 48 hours on any surface, from counter to curtain.  

Can a flu shot give you the flu?
No. Viruses in a flu shot are inactivated (killed), which means they cannot cause infection. Vaccine manufacturers test batches to make sure they are safe. 

Can the nasal spray flu vaccine give you the flu?
No. Unlike the flu shot, the nasal spray vaccine does contain live viruses. However, the viruses in the nasal spray flu vaccine are attenuated (i.e., weakened), which means they cannot cause the flu. These weakened viruses are also cold-adapted, which means they are designed to only cause mild infection at the cooler temperatures found within the nose. These viruses cannot infect the lungs or other areas of the body where warmer temperatures exist.

Is it better to get the flu than the flu vaccine?
No. Flu is a serious disease, particularly among young children, older adults and people with certain chronic health conditions, such as asthma, heart disease or diabetes. Any flu infection can carry a risk of serious complications, hospitalization or death, even among otherwise healthy children and adults. Therefore, the vaccine is a safer choice than risking illness to obtain immune protection.

Do I really need a flu vaccine every year?
Yes. The Centers for Disease Control and Prevention recommends a yearly flu vaccine for just about everyone 6 months and older, even when the viruses the vaccine protects against have not changed from the previous season. Immune protection from vaccination declines over time, so annual shots are needed to get the best protection.

Can getting enough vitamin D prevent the flu?
People with healthy vitamin D levels may have some measure of protection from getting the flu, although there’s not enough evidence among sources respected by the medical establishment to recommend vitamin D instead of the vaccine. The best advice is to make sure you’re getting enough vitamin D and get the flu shot.

Why get the shot if they base it on last year’s virus, which changes every year?
It’s like predicting earthquakes – you can’t. So we use the best science-based approach to anticipate viruses we’ll most likely encounter. Our current vaccine covers four viruses, based on viruses appearing in the Southern Hemisphere, which has winter right before we do. It’s the closest guess – and still better than not getting vaccinated.

Why do some people not feel well after getting the seasonal flu vaccine?
Some people report having mild reactions to flu vaccination. Common reactions to the flu shot and the nasal spray flu vaccine are described below.

Reactions to the flu shot:
The most common reaction to the flu shot in adults has been soreness, redness or swelling at the spot where the shot was given. This usually lasts less than two days. This initial soreness is most likely the result of the body’s early immune response reacting to a foreign substance entering the body. Other reactions following the flu shot are usually mild and can include a low-grade fever and aches — the body’s normal inflammatory response. If these reactions occur, they usually begin soon after the shot and last 1 to 2 days. The most common reactions people have are considerably less severe than the symptoms caused by actual flu illness.

Reactions to nasal spray flu vaccine:
People also may have mild reactions to the nasal spray vaccine. Some children and young adults 2 to 17 years of age have reported experiencing mild reactions after receiving nasal spray flu vaccine, including runny nose, nasal congestion or cough, chills, tiredness/weakness, sore throat and headache. Some adults 18 to 49 years of age have reported runny nose or nasal congestion, cough, chills, tiredness/weakness, sore throat and headache. These side effects are mild and short-lasting, especially when compared to flu symptoms.

What about serious reactions to flu vaccine?
Serious allergic reactions to flu vaccines are very rare. If they do occur, it is usually within a few minutes to a few hours after the vaccination. Seek immediate medical care or call 911.

What about people who get a flu vaccine and still get sick with flu-like symptoms?
Here are the main reasons you might get a flu-like illness, even after getting vaccinated: 

1. The vaccine only protects against flu viruses, not other viruses. Some people can become ill from other respiratory viruses such as rhinoviruses associated with the common cold, cause symptoms similar to flu, and also spread and cause illness during the flu season. 

2. You can be exposed to flu viruses shortly before being vaccinated or during the two-week period after vaccination needed for the body to develop immune protection. This exposure may result in getting the flu before the vaccine takes effect.

3. People may experience flu-like symptoms despite being vaccinated if they may have been exposed to a virus that is very different from the viruses the vaccine is designed to protect against. The protection ability of a flu vaccine depends largely on the similarity or “match” between the viruses selected to make the vaccine and those spreading and causing illness. This happens rarely and is not a reason to avoid vaccination.