Does the Flu Shot Prevent Stomach Flu?

Man about to vomit
Flu shots don't prevent stomach flu. Rubberball Productions/Brand X Pictures/Getty Images

You think you are going to be proactive this year and get a flu shot. All goes well, then a few weeks or months later you start getting cramps in your stomach. Then the vomiting and diarrhea start and later you might even get a fever. All you can do is lay on the floor in the bathroom waiting for this to pass. What is going on? Wasn't the flu shot supposed to prevent all of this?

Do flu shots prevent the stomach flu or not?

What's Going On?

Unfortunately, the answer is no. Flu vaccines do not prevent the stomach flu. This is because the "stomach flu" is not a type of the flu at all. It is caused by a virus, or in some cases a bacteria, but it is not related to the influenza virus that causes seasonal flu. It is more accurately known as gastroenteritis and is commonly referred to as the stomach flu.

Sadly, there is no vaccine to prevent most types of gastroenteritis. If you get it, you just have to suffer through. You should know what to watch for if you do have these symptoms, however, so you know when you should go to the doctor for vomiting and diarrhea. Dehydration is the most common reason you may need medical treatment if you have these symptoms. Dehydration can be dangerous if it isn't treated.

If you are vomiting, follow these steps to try to get it under control.

Trying to drink too much too quickly or eating solid food too soon are common reasons people continue vomiting. If vomiting persists even after you follow these instructions, contact your health care provider to find out if you need further treatment. 

There is a vaccine given to young children to prevent rotavirus - which is one of the most severe causes of gastroenteritis in kids.

It has drastically reduced the number of outbreaks of rotavirus in the developed world where it is routinely given. 

One of the most common causes of gastroenteritis in people of all ages is norovirus. Once called the "cruise ship virus" because it frequently caused outbreaks on cruise ships, it is highly contagious and causes significant vomiting and diarrhea. Fortunately it is typically self-limiting, meaning it goes away on its own after a few days. 

Could It Still Be Influenza?

Occasionally, people who have the seasonal flu will have vomiting and diarrhea, but they will also have symptoms of an upper respiratory infection  (coughing, sore throat, headache and minor congestion) and are typically children. H1N1 causes vomiting and diarrhea more frequently than other types of seasonal flu, but other symptoms such as a sore throat or a cough are present as well. When the only symptoms are vomiting, diarrhea and possibly fever, what you most likely have is a stomach virus, not the flu.

A Word From Verywell

Just because you get sick, don't make the mistake of believing the flu shot didn't work! Getting the "stomach flu" is not the same as having influenza. Still not convinced? We have plenty of information on how and why people get sick after getting the flu vaccine.

Far too many people avoid them because they think they don't work or they can make you sick. 

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