Everything to know about the flu

Aug. 26, 2021
A man and a child visit with a medical provider virtually.
One of the best ways to see a provider, without leaving the comfort of your home, is to schedule a video visit. Photo: Getty Images.

What exactly is the flu? 

The flu is a respiratory illness caused by the influenza virus. There are four types of the virus, but only two (A and B) are responsible for the yearly outbreaks we call flu season, which typically stretches from September to March and sometimes into April. The disease is highly contagious and spreads primarily through respiratory droplets let loose when a person sneezes or coughs. The virus changes from year to year and that’s why we need a new flu shot every year.

Peak activity in flu season. Source: CDC

Why should I worry about it?

The flu is not the common cold. It’s more dangerous and can make people critically ill. Its symptoms, including fever and body aches, are more intense and last longer than a typical cold. For most people, it causes a week or two of misery before recovery, but the most recent flu season also produced at least 410,000 hospitalizations and at least 24,000 deaths in the United States, according to Centers for Disease Control and Prevention (CDC).

For a detailed analysis of the toll of influenza over the past decade, click here.

To prevent a “Twindemic” or a double epidemic of COVID-19 and flu, we must get vaccinated, take proper precautions and respond to symptoms.

What’s the prediction for flu season 2021-2022?

Experts predict that this year’s flu season could be severe. The coming flu season may be severe. Here’s why – CNN

a graphic showing percentage of visits for influenza-like illness by age group
Source: CDC

How do I protect myself against the flu? Get your flu shot, of course.

The best move is to get vaccinated. Doing so isn’t a guarantee against infection, but it does lessen the risk considerably to yourself and others. And as Dr. Emily Valenta, who practices family medicine at UCHealth Primary Care – Rockrimmon in Colorado Springs notes, getting the vaccine decreases the chances that you’ll have to go to the hospital or visit the emergency department because of the flu.

“That’s more important this season than ever before,” Valenta said.

How does the flu vaccine help?

The vaccine, though not a foolproof protection against influenza, greatly increases your chances of warding off illness and protecting others from it. That, in turn, will prevent trips to the emergency room and the hospital and reduce stress on health care workers and facilities.

Flu season also brings with it plenty of questions about the disease and the need for vaccinations. Herewith, some answers.

Also very important are the basic public health steps most of us have followed for months now in the wake of COVID-19. These include frequent hand washing, maintaining social distancing, wearing masks, and sneezing or coughing into the crook of the arm rather than the hands.

Just what is the vaccine?

The flu vaccine contains pieces of the influenza virus, or antigens. Once administered, our immune systems learn to recognize the enemy and produce armies of antibodies to protect against it. The available shots are trivalent (which protects against two strains of Type A influenza and one of Type B) and quadrivalent (which adds protection against another, rarer strain of Type B). Some, but not all, people ages 2 through 49 can receive a nasal spray vaccine that protects against all four strains of the A and B viruses.

Is one vaccine better than the others?

No. “They are equivalent in terms of protection,” Valenta said. As noted above, the nasal spray vaccine isn’t for everyone.

Is Moderna developing an mRNA flu vaccine?

Yes, Moderna is developing mRNA-1010 to protect against common flu strains as recommended by the World Health Organization. The company is hoping to improve on traditional flu shots which are typically about 40% to 60% effective.

Who should get vaccinated?

The short answer is everyone who is six months of age and older. There are only rare exceptions. It is particularly important for people ages 65 and older to get a flu vaccine, Valenta said.

“This is certainly a group that we have identified as high risk and will obviously benefit more from getting vaccinated,” she said.

The CDC also emphasizes the importance of vaccinating children younger than five years old because of their risk of developing serious complications if they are infected by the virus. A list of all groups at highest risk of flu-related complications is available here.

When should I get vaccinated?

It’s always best to do so as early as possible. Get vaccinated now. It’s especially important to get your flu shot this year because of the added challenges that COVID-19 will cause.

“The earlier you can protect yourself, the better,” Valenta said.

When will vaccinations be available?

Flu vaccines are available now. Patients with UCHealth can schedule appointments online through My Health Connection, the patient portal. Many other sites will offer the vaccine, including some for free or at reduced cost. The Colorado Department of Public Health and Environment (CDPHE) has more information on available locations throughout the state.

I’ve never gotten the flu and I have no health problems. Why should I get vaccinated?

Valenta said she hears this objection often from patients. I usually respond to this by comparing it to any other preventive measure such as a seatbelt,” she said. “I ask them if they have ever been in a bad car accident and if they say ‘no’ I ask them if they still wear a seatbelt.” That example seems to sway most patients, she said.

Valenta added that she also explains the concept of herd immunity – the idea that increasing the number of vaccinated people reduces the risk of the virus spreading through the community. More people with immunity means fewer opportunities for the virus to find victims – especially the most vulnerable, Valenta said.

With the delta variant causing a spike in the number of people needing to be hospitalized, getting a flu shot helps protect you and frontline health care workers who are tending to the ill in clinics and hospitals.

I got vaccinated and I got the flu. Why would I do that again?

Simply put, “there is no way to get the flu from the flu shot,” Valenta said. That’s because the trivalent and quadrivalent vaccines contain particles of the influenza virus that have been rendered inactive in the laboratory. The nasal spray contains live viruses that have been “attenuated,” or weakened in the laboratory such that they don’t cause disease.

So what causes the post-vaccination symptoms that people mistake for the flu itself? “What people experience is a brief reaction that typically lasts 24 to 48 hours and involves some low-grade fevers and muscle aches or soreness at the site of injection,” Valenta said. The symptoms are an over response by the immune system to the vaccine that “people commonly misinterpret as the actual influenza infection itself,” she added.

Where can I get more information about the flu?

The CDC is the most comprehensive source. The Colorado Department of Public Health and Environment provides regularly updated data for the state of Colorado.

About the author

Katie Kerwin McCrimmon is a proud Coloradan. She attended Colorado College thanks to a merit scholarship from the Boettcher Foundation and worked as a park ranger in Rocky Mountain National Park during summers in college.

Katie is a dedicated storyteller who loves getting to know UCHealth patients and providers and sharing their inspiring stories.

Katie spent years working as an award-winning journalist at the Rocky Mountain News and at an online health policy news site before joining UCHealth in 2017.

Katie and her husband, Cyrus — a Pulitzer Prize-winning photographer — have three adult children and love spending time in the Colorado mountains and traveling around the world.