Everything You Need to Know About Flu Season

By Irmanie Hemphill, MD, FAAFP
Medically reviewed checkmarkMedically reviewed
November 3, 2021

Ah, flu season. If there’s one thing you can depend on every year, it’s the flu coming back into collective consciousness and wreaking havoc on communities across the country.

The CDC estimates that between 9 million and 41 million people catch the flu (or, the influenza virus) each year, and most of these cases occur during what is known as “flu season.”

In this article, we’ll talk about what flu season is and when it starts, as well as the best ways to protect yourself and your loved ones amid the spread—including when it’s necessary to see a doctor if you do come down with it.

Being educated is one of the best steps towards staying safe and healthy, so read on to learn all you need to know before the flu comes after you. 

What is Flu Season?

While the influenza virus is active year round, flu season is the period of time when the influenza virus is at its most active, meaning cases are up and you are more likely to become infected.

Typically, this season begins in the fall (generally October), when it starts getting colder, and ends in the spring (generally April or May), when it starts getting warmer.  

When Does Flu Season Start?

There’s no fixed date that marks the start of flu season; the exact timing changes every year and varies between areas of the country.

That said, October tends to be the month when cases start ramping up again every year, and December to March is when cases are at their peak. 

According to data collected by the CDC, for the past several decades, February has been the month when the most cases are reported, followed by December, March, and then January. 

In addition to the influenza virus, there are several other respiratory viruses that can spread during flu season and are often confused with the flu.

These include rhinovirus, which is one of the viruses that causes the common cold, and respiratory syncytial virus (RSV), which can be severe—and even deadly—in young children and older adults. 

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Best Ways To Protect Yourself From the Flu

Though the flu is contagious, there are several easy and effective ways to protect yourself from being infected by the flu this season. 


Just like with COVID-19, masks can be extremely effective when it comes to preventing getting infected with the influenza virus.

Again, like with COVID-19, experts believe that the influenza virus is most often transferred to others through tiny droplets when an infected person speaks, coughs, or sneezes.

A well-fitting face mask can prevent these tiny droplets from getting near your nose and/or mouth and infecting you. 

Hand washing

Proper hygiene is so important when it comes to keeping the influenza virus at bay, and washing your hands is one of the best ways to keep everything clean and under control.

Thoroughly (and frequently) washing your hands with soap and water is important; if you are out and about and don’t currently have access to soap, using an alcohol-based hand sanitizing solution is the next best thing, according to the CDC.


According to the CDC, getting the influenza vaccine (typically referred to as the flu shot) is the most important step in preventing the flu.

It can greatly reduce your likelihood of being hospitalized for, or dying from, the flu. 

The flu shot is recommended for everyone six months and older (with a few exceptions) and is especially important for those who are at a higher risk of developing serious flu complications.

As far as timing, it also recommended that you get it before the end of October—but if it’s after that time and you still haven’t gotten the vaccine, it’s not too late.

The shot is typically free of cost, and can even be received at the same time as the COVID-19 vaccine. And if you’re scared of needles, there’s an option for you, too: a nasal spray.

When To See a Doctor

Most people who get the flu can recover on their own with rest, hydration, and proper self-care—but there are certain people who should seek out help from a medical professional to ensure that complications don’t turn deadly. 

According to the CDC, people at a greater risk of developing complications from the flu include adults 65 and older, adults with chronic illnesses, pregnant people, young children, people with disabilities, and more.

If you are in one of these groups, or think you have come down with a severe case of the flu, be sure to check in with your doctor, who may prescribe you an antiviral medication to help with the severity and/or duration of your symptoms. 

Without proper care, the flu can lead to more serious conditions, like pneumonia, bronchitis, and sinus infections, which can lead to hospitalization and even death. The flu can also worsen chronic health conditions, like asthma and congestive heart failure.

How K Health Can Help

If you want to talk to a doctor about getting the flu shot, think you or a loved one have come down with the flu, or want more information on how to best treat symptoms, K Health and their trusted team of medical professionals are here to help. 

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Download K Health to check your symptoms, explore conditions and treatments, and, if needed, text with a doctor in minutes. K Health’s AI-powered app is HIPAA compliant and based on 20 years of clinical data.

Frequently Asked Questions

Why is flu season usually during the winter months?
While flu season is often seen as synonymous with the winter season, the medical field actually hasn’t determined exactly why the influenza virus becomes more active in the winter, though it is generally accepted that the cold weather is a primary catalyst.
Can you take more than one flu shot in the same season?
According to the CDC, studies have shown that there is no benefit to getting more than one flu shot in the same season. (This is different in the case of certain children, who may need two.) That said, it’s best to stick with one per season.
How can the flu virus come back every year?
The flu comes back year after year because the virus continues to evolve, therefore evading the immune system and any antibodies you may have developed. This is why flu shots protect against multiple variations of the virus, and why it’s important to get a flu shot every year.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Irmanie Hemphill, MD, FAAFP

Dr. Hemphill is an award winning primary care physician with an MD from Florida State University College of Medicine. She completed her residency at Halifax Medical Center.