Medically reviewed by: Dr. Leonard, DO — Midwest Express Clinic
Author: Midwest Express Clinic Medical Team
Last reviewed: September 11, 2026
With the fall season in full swing, now is the time to get ahead of the upcoming flu season with an annual flu vaccination. Early fall, ideally between mid-September and the end of October, is the best time for most people to get a flu shot. Scheduling a flu shot in this time frame allows your body to build immunity before flu activity begins to increase. Read on to learn more about flu shot timing, who should consider getting vaccinated sooner, how long it takes for a flu vaccine to work and what to expect during your flu shot visit.
What Is a Flu Shot?
A flu shot is a vaccine that helps protect your body against influenza, a contagious respiratory virus. Each year, the flu vaccine is updated to target the strains of the virus expected to circulate most widely during the upcoming flu season. While the flu vaccine cannot guarantee you won’t get infected, it can help lower your overall risk of infection and may reduce the severity of symptoms as well as the duration of illness.
When Is the Best Time to Get a Flu Shot?
For most people, the best time to get a flu shot is in September or October, before influenza begins spreading widely. Health experts recommend getting vaccinated by the end of October at the latest to ensure you build up immunity by the time flu cases start trending upward. However, if you miss that window, don’t skip your vaccination. Flu activity often continues through the winter and into the spring, so getting vaccinated later is still beneficial.
After receiving a flu shot, your immune system needs time to build immunity. It typically takes about two weeks for your body to develop protective antibodies, proteins made by your immune system that help recognize and fight infections. During those two weeks, you can still get infected if you’re exposed to the flu virus. That’s why it’s important to get vaccinated before flu season reaches its peak to help ensure your immune system is fully prepared to fight the virus. Getting vaccinated too early, such as during the summer, may result in reduced protection during flu season because the body’s immunity gradually decreases over time.
Who Should Get Vaccinated First?
Although annual flu vaccination is recommended for nearly everyone 6 months and older, some people should consider getting vaccinated earlier because they are at greater risk of serious flu-related health complications or are more likely to be exposed to the virus due to their work/living environment. These higher-risk groups include:
- Adults age 65 and older: Aging naturally weakens the immune system, which increases the risk of severe illness and hospitalization in older individuals.
- Young children: Infants and young kids have immune systems that are still developing, and thus may not be able to fight off the flu virus as effectively.
- Pregnant individuals: Pregnancy increases the risk of severe illness from the flu virus. Vaccination during pregnancy also helps provide protection to newborns during their first few months of life.
- People with chronic health conditions: The flu can worsen underlying conditions in individuals with weakened immune systems or chronic health issues such as asthma, diabetes, heart disease or chronic lung disease.
- Residents of long-term care facilities, caregivers and healthcare workers: Individuals who work or live in environments such as hospitals and long-term care centers are more likely to be exposed to the flu virus and can help protect other vulnerable people by getting vaccinated.
Getting a flu vaccination each year not only protects you but also helps reduce the spread of the virus within your household and the community at large.
Flu Shot Timing Recommendations
The following timing recommendations for flu shot administration are based on the current guidelines provided by the U.S. Centers for Disease Control and Prevention.
| Situation | Timing Recommendation |
| Most children and adults | September and October |
| Adults 65 and older | September and October, unless otherwise instructed |
| Children 6 months to 8 years old getting a flu shot for the first time | Early September, need 2 doses given 4 weeks apart |
| Pregnant individuals | Any trimester, as soon as flu vaccine is available |
| Traveling during flu season | Aim to get vaccinated at least two weeks before travel |
Does Getting a Flu Shot Give You the Flu Virus?
No. The flu shot cannot give you the flu because the vaccine doesn’t contain a live strain of influenza virus capable of causing infection. Some people experience mild side effects such as fatigue, low-grade fever or soreness at the injection site after vaccination. These symptoms are normal and typically last between 24 to 48 hours after getting a flu shot.
What Happens During a Flu Shot Visit?
Getting a flu shot at Midwest Express Clinic is a quick and straightforward process. During your visit, your urgent care provider will:
- Review your medical history.
- Answer any questions you may have about the vaccine.
- Confirm that you’re eligible for flu vaccination.
- Administer the flu shot.
- Review common side effects and when to seek medical care if needed.
Most flu shot visits take only a few minutes, and you can typically return to your normal activities immediately afterward.
Are Side Effects Common After Getting a Flu Shot?
Most flu shot side effects are mild and temporary. They are a normal sign that your immune system is responding effectively to the vaccine. Side effects usually improve within 24 to 48 hours without additional treatment. Common side effects can include:
- Soreness, redness or swelling at the injection site
- Fatigue or muscle aches
- Low-grade fever
- Headache
Serious allergic reactions are uncommon. If you have a history of severe allergic reactions to vaccines or specific vaccine ingredients, discuss your medical history with your primary healthcare provider before getting vaccinated.
When to Go to the ER or Call 911
Although severe reactions to flu vaccines are rare, it’s crucial to seek emergency medical care immediately if you or a loved one experience:
- Swelling of the face, lips, tongue or throat
- Difficulty breathing
- Severe hives
- Loss of consciousness
- Severe dizziness that does not improve
Call 911 or go to the nearest emergency room if any of these symptoms occur after receiving a flu vaccination.
Find Same-Day Flu Shot Services at Midwest Express Clinic
Midwest Express Clinic makes it easy to protect yourself and your family with convenient walk-in flu vaccination and treatment services available at over 50 clinic locations. If you have questions about when to get a flu shot or what type of vaccine you need, experienced urgent care providers are here to help you make informed decisions about your health all season long. For more information about flu shot services at Midwest Express Clinic, visit midwestexpressclinic.com/flu-shots.
Use Online Check-In before your visit to save time and make getting your annual flu shot even more convenient for your schedule. To find a Midwest Express Clinic location in your area, visit midwestexpressclinic.com/locations.
