Why the flu shot can't cause the flu and why you should get vaccinated now

One of the common myths that causes people to avoid the flu shot is that they think the shot will cause them to catch the flu. But that's just not true. The virus in the vaccine is inactive, an inactive virus cannot transmit diseases. What is true is that effects resulting from the immune response may be felt. But that doesn't mean you have the flu

By: Libby Richards, Associate Professor of Nursing, Purdue University

Vaccination against influenza prevents the morbidity of millions of patients and many deaths caused by influenza every year, but vaccination rates are low for many reasons.

During the 2019-2018 flu season, the Centers for Disease Control and Prevention reported that approximately 45% of adults in the US received the flu vaccine. While this is an 8% increase from 2018-2017, it falls far short of the national goal of 70% of American adults who were supposed to receive the vaccine.

One of the common myths that causes people to avoid the flu shot is that they think the shot will cause them to catch the flu. But that's just not true. The virus in the vaccine is inactive, an inactive virus cannot transmit diseases. What is true is that effects resulting from the immune response may be felt. But that doesn't mean you have the flu.
I'm a nursing professor with experience in public health promotion, and I often hear myths of this and that. Below are the facts and the explanations behind them.

Inactive virus

Influenza is a common but serious infectious respiratory disease that can cause hospitalization and even death. The CDC estimates that during a "good" flu season, about 8% of the US population may get the flu - about 26 million people.
Every year the flu season is different, the flu virus also affects people differently. One dangerous complication of the flu is pneumonia, which can occur when your body is working hard to fight the flu. This is especially dangerous among adults, small children, and those whose immune system is not working, such as people receiving chemotherapy treatments.

History remembers millions of Americans getting sick with the flu every year, hundreds of thousands hospitalized and tens of thousands of people dying from complications related to the flu. During the 1918 flu epidemic, a third of the world's population, or about 500 million people, contracted the flu. Since that time, the science of vaccines has dramatically changed the control of the spread of infectious diseases.

The cornerstone of flu prevention is vaccination. The CDC recommends that everyone six months of age and older who does not have a contraindication to the vaccine get the flu shot. Just like the polio vaccine will not cause children to get polio, the flu vaccine will not cause the flu. This is because the flu vaccine is made with inactive strains of the flu virus, which are unable to cause the flu.

However, some people may feel sick after receiving the flu shot which may make them think they have gotten sick from the shot. That feeling after a flu shot is actually positive. This could be a sign that the body's immune response is working properly. What happens is that when a person receives the flu shot, their body recognizes the inactive flu virus as a foreign invader. It is not dangerous but this detection causes the immune system to develop antibodies that will attack the flu virus when it is exposed in the future. This natural immune response may cause some people to develop a low-grade fever, headache or general muscle aches. These side effects can be mistaken for flu symptoms, but in reality, this is the body's normal response to the vaccine.

And the good news is that these natural symptoms are short-term side effects compared to the flu, which can last longer and is more severe. It is estimated that less than 2% of people who receive the flu vaccine will develop a fever.
Also, people often confuse a bad cold or an upset stomach with the flu. Flu symptoms can include fever, chills, sore throat, runny nose, body aches, fatigue and headaches. Symptoms of the body's resistance to the vaccine can be similar to the flu but are usually milder. The stomach flu, or inflammation of the digestive system, can be caused by several different bacteria or viruses. Symptoms of gastroenteritis include nausea, vomiting and diarrhea.

Some people do get the flu after getting a flu shot, but it's not from the shot. This can happen for several reasons.
First, they could have been exposed to the flu before going to get the shot. It takes up to two weeks after receiving the flu shot to develop full immunity. Therefore, if you get the flu during this time, it is likely that you were exposed to the flu before you were vaccinated or before your full immunity developed.
Second, depending on the strain of flu virus you are exposed to, you can still get the flu even if you have received the vaccine. Every year, the vaccine against the influenza virus that is most suitable for the most common strain of the virus is created. Therefore, the effectiveness of a flu vaccine depends on the similarity between the virus that infects the community and the dead viruses used to make the vaccine.

If there is a close match between the two, then the effectiveness of the flu vaccine will be high. However, if there is no close match, the effectiveness of the vaccine can be reduced. It must be noted that even when there is no close match between the circulating virus and the virus used to produce the vaccine, the vaccine will still reduce the severity of flu symptoms and will also help prevent flu-related complications.

Bottom line: You cannot get the flu due to a flu vaccine. As someone who has taken care of many people who are sick with the flu, I strongly recommend that you get vaccinated.
to the article on The Conversation website