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Ask the expert COVID-19
Last updated August 7, 2020. 4 minute read

The flu shot and the novel coronavirus

Cases of the flu can be prevented by vaccination to decrease the number of people who get sick every year. Given the strain on the healthcare system that may occur with novel coronavirus, it is very important that we do all that we can to decrease infections from other sources, including the flu.

Dr. Zachary Porterfield, MD, PhD

Dr. Zach Porterfield is a physician scientist with specialization in virology and global health. He completed his Infectious Disease clinical training at Yale University and currently directs global health research projects in multiple countries in Africa and the United States.

Reviewed by Dr. Tzvi Doron, DO

What is the flu?

The flu, also known as influenza, is a common and highly contagious infection of the lungs, nose, and throat caused by the influenza group of viruses. It typically causes fever, cough, sore throat, muscle aches, and headache and is more common in the winter months. The flu is spread from person to person by tiny droplets that are created when a person coughs, sneezes, or talks. It typically spreads when there is close contact between individuals but can also spread by shared contact with solid surfaces.

Most flu infections last 1–2 weeks, and the body can often recover from the infection on its own. Despite being relatively common, it is often underappreciated how dangerous the flu can be. Each year, between 5% and 20% of the US population gets sick with flu, and between 12,000 and 61,000 people die as a result, with most of these deaths happening in people who are older or have other chronic health problems. There are both treatments for people who have the flu and also vaccines to decrease the chance of catching the flu. While vaccination is the best way to avoid getting infected, additional steps that can be taken include frequent hand washing, avoiding touching your eyes, nose, and mouth, limiting contact with sick people or staying home if you have the symptoms of the flu, and coughing or sneezing into a tissue followed by throwing this tissue away and washing your hands.

When you get vaccinated against the flu, it not only decreases your chance of catching the flu, it also decreases how sick you get if you do happen to catch the flu.

What is the flu shot, and should I get it?

The flu shot, or influenza vaccine, is a way to both keep you from catching the flu and to decrease how sick you become if you do catch the flu. Vaccines work by giving your body exposure to an inactive or weakened form of an infectious agent. This lets your immune system develop an ability to fight off that specific infection if you get exposed to it again later. Vaccines use your body’s natural system of fighting infections and teach it to fight a specific infection before you encounter it.

The flu vaccine is recommended for everyone older than six months of age, including children, the elderly, people with weakened immune systems, and pregnant women. The only exceptions to this recommendation are for individuals who have had a severe reaction to the flu vaccine in the past or those who are currently moderately or severely ill. Those individuals who are ill should get the flu vaccine once they recover from the illness.

There are several different types of flu vaccine—your healthcare provider can help you determine which one is the best for you.

Does the flu vaccine have side effects?

All medical treatments have risks. The most common side effect of the flu vaccine is soreness at the site of injection and runny nose or congestion from the vaccine given by spray in the nose. Very rarely, the flu vaccine can cause fever, and in exceptionally rare cases (~1 case per million vaccines given), it has been associated with a problem with the nervous system called Guillain-Barré syndrome. Despite these possible side effects, the flu vaccine is recommended for everyone, because the benefits of vaccination greatly outweigh these risks.

There are quite a few concerns about the flu vaccine—is there any truth to these concerns?

There is quite a bit of misinformation regarding the flu and the flu vaccine. Some of the more common ones include:

Myth: Getting the flu vaccine gives you the flu.
Fact: Some people have a mild reaction to the flu vaccine, and, very rarely, this can be accompanied by fever. These symptoms are not the flu. Instead, any symptoms you experience after getting the vaccine may be due to your immune system building up a defense against the flu.

Myth: Healthy people do not need to get vaccinated.
Fact: The flu vaccine is recommended for everyone older than six months of age, with very few exceptions, including a prior severe reaction to the flu vaccine or currently being ill. The flu can infect young, healthy people and can cause serious illness and even death. Getting vaccinated also helps protect other people who may not be able to get vaccinated themselves, because the more people who get vaccinated, the harder it is for the flu to spread in the community.

Myth: Pregnant women cannot get the flu shot.
Fact: Pregnant women are at increased risk of getting severely ill from the flu and are one of the key groups who should be vaccinated.

Are the flu and the current outbreak of novel coronavirus related?

Influenza viruses and the novel coronavirus, which is currently causing an outbreak of a disease called coronavirus disease 2019 (COVID-19), are different viruses—but they have some similarities. Many viruses, including novel coronavirus, can cause symptoms similar to the flu, including fever and cough. While there are treatments and vaccines for the flu, we do not yet have an FDA-approved treatment or vaccine for the novel coronavirus (although testing of some possible medications and vaccines is underway). The additional techniques used to prevent transmission of flu (frequent hand washing, avoiding touching your eyes, nose, and mouth, limiting contact with sick people or staying home if you have flu-like symptoms, and coughing or sneezing into a tissue followed by throwing this tissue away and washing your hands) work to help prevent transmission of the novel coronavirus. 

Cases of the flu can be prevented by vaccination to decrease the number of people who get sick every year. Given the strain on the healthcare system that may occur with the novel coronavirus, it is very important that we do all that we can to decrease infections from other sources, including the flu. Getting the flu vaccine will not only help keep you from getting sick but will also help our healthcare workers focus on taking care of people who need their help most. Additionally, the novel coronavirus can be much more dangerous in those individuals who have a weakened immune system. Infection with the flu weakens the immune system and raises the risk of serious illness and even death from the novel coronavirus.
 
When you get vaccinated against the flu, it not only decreases your chance of never catching the flu, it also decreases how sick you get if you do happen to catch the flu. Additionally, getting the flu vaccine helps protect people around you from getting sick. This is especially true for those people who are at high risk of getting seriously ill from the flu, including the elderly, children, pregnant women, and those people who have weakened immune systems or chronic diseases. When a majority of people in a community get vaccinated against a disease, this creates a situation in which the disease cannot spread easily and dramatically helps with ending outbreaks (this is called herd immunity).