Every year the old, “are flu shots necessary, effective, or dangerous?” questions arise right around the time the flu vaccine becomes available. Ultimately this is a decision you should make in consultation with your doctor who knows your medical history and underlying health issues. Always talk to your healthcare provider if you have questions or concerns about your health.
In the meantime, the U.S. Department of Health & Human Services1, the National Health Service (UK)2, and The Government of Canada3 have a pretty consistent message: if your doctor says you are able, it’s important to get the flu shot every year; it’s safe; and it will not give you the flu.
The reason it’s important to get the flu shot is simple: the flu isn’t just a bad cold; it’s a nasty, contagious virus that has the potential to be fatal. Pregnant women and people with weakened immune systems like the elderly, babies and young children, and people with cancer; as well as those with heart disease, asthma, and diabetes have an increased risk of developing serious complications from the flu.
You can shed the virus and pass it on to others before you’re even showing symptoms, which means you’re contagious starting one day before the first symptoms until about five days after the first symptoms.4 Protecting yourself is critical—because when you do, you’re protecting others too.
Flu vaccines don’t cause the flu
The myth that the flu shot gives you the flu circulates every year. The vaccine either contains flu viruses that have been inactivated (killed), or uses just a single gene from a flu virus, as opposed to the full virus. In both cases, all this does is produce an immune response in your body, making it less likely that you will be infected if you do come into contact with someone who has the flu.5 That means you might feel a little under the weather for a few hours and up to a day or two after your shot, but it does not mean you have the flu. What you’re experiencing is simply your body doing what it should by figuring out how to protect itself.
Flu vaccines aren’t 100% effective, but they’re still important
The flu virus is a moving target because it mutates so quickly. Scientists base each year’s vaccine formula on a “best guess” for which strain is going to be circulating, so they are never 100% effective.6
However, if you get the flu shot and do end up with the flu, it can reduce the severity of your symptoms.
The flu shot isn’t effective immediately, so get it early
It takes two weeks for your body to develop immune protection after receiving the shot, which is why it is recommended that you get it as soon as it becomes available in October or November.
However, since flu season can often run into early spring, it’s a good idea to get it no matter how late in the season it is.
When you get the flu shot, you help protect those around you
In addition to those who are at risk of severe complications from the flu, there are people who can’t get the flu shot. When you get the vaccine, you’re lowering your risk of contracting the virus. And when you’re doing everything you can to stay healthy, the people around you—your family, friends, coworkers, and neighbors—have a better chance of staying healthy too.
The decision to protect yourself by getting the flu shot and other vaccines is a personal one, but it’s important to be as well informed as possible when making that decision. Talk to your doctor and research using reputable sources.
For more information about the flu shot, including common misconceptions, visit CDC.
3, 4 https://www.canada.ca/en/public-health/services/diseases/flu-influenza/get-your-flu-shot.html
417413F CAN/US (12/19)