Here’s What You Need to Know About Getting a Flu Shot
Medically Reviewed by Dr Samantha Miller, MBChB
Influenza, or the flu, is a respiratory tract infection caused by a number of influenza viruses. It’s especially prevalent during the autumn and winter months. The flu is very common, and most people have experienced it at least once in their lives. Influenza is also highly contagious and can quickly spread throughout workplaces, households, schools and public areas.
The flu spreads when people expel tiny droplets laden with viral particles from their noses and mouths while coughing, sneezing, talking and even breathing. These droplets also survive on surfaces. Those who are nearby when an infected person expels viral droplets may inhale those droplets and become infected themselves.
Most people who get the flu have a mild case of the illness that isn’t life-threatening and normally goes away on its own after a few days or a little longer. However, influenza viruses can cause serious infection and even death in vulnerable people.
To avoid contracting or spreading the flu, it’s important to maintain good hygiene practices, such as washing your hands frequently and covering your mouth and nose when coughing or sneezing. If you’re feeling unwell it’s best to stay home and avoid contact with vulnerable individuals to reduce the risk of passing the illness to them. But the most effective way to protect against seasonal influenza is to get a flu shot each year. Here’s what you need to know about getting vaccinated against the flu.
Types of Influenza Vaccines
The regular flu shot is a vaccine that contains non-infectious versions of the three or four types of flu viruses research has indicated will be most common that year. This type of vaccine, known as an inactivated influenza vaccine, uses eggs to grow the virus before it’s later inactivated. The vaccination prompts your body’s immune system to produce antibodies that it can later use to fight off seasonal flu viruses and reduce your risk of getting sick.
The high-dose inactivated influenza vaccine contains a greater quantity of non-infectious viral particles. It’s licensed for use in people over the age of 65 in the United States. The higher dose in this type of vaccine aims to promote a better immune response in this age group — and therefore offer better protection against seasonal influenza.
All inactivated influenza vaccines are administered using a needle into the skin (called intradermal injection) or muscle (called intramuscular injection) of the upper arm. A trained healthcare professional needs to administer these vaccines.
The live attenuated influenza vaccine is another type that’s administered via a nasal spray. This vaccine contains active viral particles that have been weakened so they can’t cause infection. This type of vaccine isn’t licensed for use in certain individuals such as pregnant people or people with weakened immune systems. It’s only recommended for individuals between the ages of 2 and 49 years. It also contains particles from four influenza strains.
Lastly, the recombinant influenza vaccine is a type that’s manufactured without the use of eggs. This type may be suitable for people who are allergic to eggs.
It’s helpful to get vaccinated early on during flu season because it can take a few weeks for your body to respond to the shot and create the protective antibodies needed to keep you from getting sick with the flu. The immunity you develop from being vaccinated is most effective against the year's common strains of flu. The strains that cause illness change (mutate) each year. So, the vaccine is adjusted each year to target the specific viruses that are thought to be circulating. That’s why it’s essential to get vaccinated every year.
Who Should Get a Flu Shot?
The Centers for Disease Control and Prevention recommends that everyone over the age of 6 months get a flu shot, as long as the vaccine that’s formulated to create immunity to that year’s prominent strains are designed to be safe based on the recipient’s age and health status. Some vaccines aren’t designed for all age groups; for example, the recombinant influenza vaccine is only approved for use in people who are age 18 or over. Your physician will be able to recommend the right type of vaccine for you based on your current health, age and other factors.
It’s particularly important for people who might develop severe complications if they become infected with seasonal influenza to get a flu shot each year. The CDC notes that the following individuals are at a higher risk of developing severe complications related to the flu:
- Children under the age of 5
- Adults over the age of 65
- Pregnant people
- People with certain medical conditions, including asthma, chronic lung disease, heart disease, kidney and liver disorders, blood and endocrine disorders, immune disorders, obesity and neurological disorders
- Individuals, such as healthcare providers and caregivers, who are often in contact with high-risk individuals
Who Should Not Get a Flu Shot?
The flu shot is suitable for most people. However, it’s important to consult your physician before receiving a flu shot to make sure there’s no contraindication, meaning you don’t have another condition or health issue that could worsen because you got vaccinated. The flu shot may not be suitable for:
- Individuals with an allergy to eggs — ask if an egg-free vaccine is available to you
- Those who’ve had a reaction to a flu shot in the past
- Anyone who’s ever had Guillain-Barré Syndrome (GBS), a neurological illness that can occur after a person receives a vaccination — this can result in long-term paralysis
Even if you’ve never had a reaction to the flu shot when you’ve gotten vaccinated before, you should talk to your doctor before you receive the shot. They can advise you about side effects and other important information they want you to be aware of.
If you’re feeling unwell on the day of your flu shot, get in touch with your physician and let them know. They may advise you to postpone your vaccination until you’re feeling better.
Are There Any Side Effects From Flu Shots?
One common misconception about the flu shot is that it can cause someone to come down with the flu. This is not true. The viruses used in flu vaccinations are inactive or weakened and cannot cause infection. However, they can cause some side effects, which are generally mild. These may include:
- Slight fever
- Mild body aches
- Swelling and redness around the area where the shot was administered
- Itchy or hardened skin in the area of your body where you got the shot
These side effects should subside shortly after you’ve gotten your flu shot, but they may last up to several days. An allergic reaction is a rare side effect of getting a flu shot, and the vaccine can cause some individuals to develop an allergic reaction called anaphylaxis. Anaphylaxis causes immediate symptoms of rash, swelling and difficulty breathing, typically within minutes of exposure to the allergen. This allergic reaction requires emergency treatment.
Resource Links:
- https://medlineplus.gov/flu.html
- https://www.cdc.gov/flu/about/keyfacts.htm
- https://www.nhs.uk/conditions/vaccinations/flu-influenza-vaccine/
- https://www.nhs.uk/conditions/flu/
- https://www.who.int/en/news-room/fact-sheets/detail/influenza-(seasonal)
- https://bestpractice.bmj.com/topics/en-gb/6
- https://www.mayoclinic.org/diseases-conditions/anaphylaxis/symptoms-causes/syc-20351468
- https://www.cdc.gov/flu/prevent/whoshouldvax.htm
