What's New With the Flu In 2021?

A repeated pattern of syringes with lavender fluid in them on a pale pink background.

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Key Takeaways

  • Last year, there were fewer influenza cases reported to the Centers for Disease Control and Prevention (CDC) than is typical of a flu season in the United States. This year, public health experts think that less face masking and social distancing could make the flu more of a threat, and they are urging people to get their flu shots—and soon.
  • While experts say that there are special shots for older adults that can help boost the flu vaccine’s effectiveness, if your doctor or flu shot clinic doesn’t have them, just get the shot that they have.
  • It's also safe to get a flu vaccine with a COVID-19 shot or booster.  

Last year, a convergence of COVID-19 related factors—including mask mandates, social distancing, and less tracking and reporting of conditions other than COVID by state public health departments, meant that the flu season in the United States seemed to be unusually light.

The Centers for Disease Control and Prevention (CDC) only recorded about 2,000 influenza cases last year (compared to 38 million cases the year before). Will this fall and winter look similar on the flu front? Or will the virus return with a vengeance?

Is the Flu Set to Make a Comeback?

Lisa Grohskopf, MD, MPH, a medical officer in CDC’s influenza division, tells Verywell that masking, social distancing, and remote school and work likely contributed to the low number of cases in 2020. However, 2021 might look very different.

“This year, school and jobs are more likely to be in person,” says Grohskopf, adding that people are now masking and distancing less, which makes it more likely that the flu will spread again. "And without the vaccine, it raises the risk of serious illness from the virus.” 

William Schaffner, MD, MPH, the medical director of the National Foundation of Infectious Diseases and a professor in the department of infectious diseases at Vanderbilt University, tells Verywell that “people often think of the flu as trivial, but it typically causes thousands of deaths each year."

According to the CDC estimates, more than 20,000 people died of flu in the U.S. during the 2019-2020 flu season. In other years, the death rates were even higher.

What's New With the Flu This Year

Each year, the World Health Organization (WHO) and the U.S. Food and Drug Administration (FDA) hold meetings to decide what needs to be included in the coming year’s flu vaccine. LJ Tan, chief strategy officer of the Immunization Action Coalition in St. Paul, tells Verwell that the decision is based on the flu viruses that are the most prevalent at the end of flu season.

Flu viruses can mutate as the season progresses, and Tan says that means a flu vaccine for a specific flu season may not be a perfect match, it's still "highly likely to protect you against severe disease and death.”

If you wait to get your flu shot later in the season, you might have to search for a doctor or clinic that has the vaccine. It's also important to keep in mind that it takes two weeks from the day that you get the shot for immunity to fully kick in. 

Flu Shots and COVID Vaccines

At first, the CDC advised that people wait at least two weeks after getting their COVID shot to get another vaccine. Now, the CDC says that COVID shots can be given with a flu vaccine (or any other vaccine) because there is no indication of immunity waning or serious side effects when the shots are given at the same time.

Flu Shots for People Who've Recently Had COVID

The CDC says people recovering from COVID-19 should wait to get a flu shot until they are no longer acutely ill. For people recovering at home, this means waiting until they meet criteria for leaving isolation in order to prevent spreading COVID-19 to others. If you had COVID symptoms, these criteria involve:

  • 10 days since symptoms first appeared and
  • 24 hours with no fever without the use of fever-reducing medications and
  • Other symptoms of COVID-19 are improving

If you didn't have symptoms, the CDC says it's safe to be around others if it's been 10 days since a positive viral test.

The CDC adds people with suspected or confirmed COVID-19 should not get a flu shot.

Flu Shots for Pregnant People

People in their third trimester of pregnancy should get the flu vaccine as soon as possible because babies cannot get their first flu shot until they're 6 months old.

Pregnant people transfer their immunity through the placenta, which means that a baby whose pregnant parent has had a flu shot before birth will have antibodies to the flu for protection until they can get their own vaccine.

Nasal Spray or Shot?

While there is a nasal spray flu vaccine available for people ages 2 to 49, Schaffner says that pregnant people should get the flu shot "because in very rare cases, the nasal spray flu vaccine has been linked to birth defects in fetuses."

Flu Shots for Kids

The first time they get immunized against the flu, children between the ages of 6 months to 8 years old get two shots. Then, they get just one dose for all subsequent flu vaccines.

However, there is a four-week delay between the two doses—and immunity is not complete until two weeks after getting the second shot. Therefore, the CDC recommends that kids who need two shots get them as soon as possible this year to ensure that they're protected.

Flu Vaccines for Older Adults

Tan says that there are special flu shots for older adults that are the better option if it's possible to get them (if not, people should get whichever flu shot is available rather than not get it at all).

Older adults often have weakened immune systems. Therefore, the preferred flu shot for older adults is either a higher dose version (Fluzone High Dose) or a version that has an added ingredient (an adjuvant) that can boost their immune response (Fluad Quadrivalent).

Hopefully, it won't be difficult for people to find the shot that's best for them because this year, all flu vaccines will contain four flu virus strains (in prior years, they contained only three). 

Still, it pays to be proactive. “Thinking early about your flu shot lets you call ahead to find a particular type of shot if that is best for you," says Tan.

Flu Shots for People With Egg Allergies

Some types of flu vaccines are made by growing the virus in chicken eggs in a lab. People with an allergy to eggs are sometimes advised to get a non-egg-based flu vaccine.

The CDC's guidelines for influenza vaccination for people with egg allergies have remained the same for the last three years. Grohskopf says that's because severe reactions are so rare.

If you have an egg allergy, it's a good idea to talk to your doctor and review the guidance when you're getting ready to get a flu shot.

  • People with a history of hives as their only allergic reaction after eating eggs can get any flu shot. 
  • People who had symptoms other than hives—including difficulty breathing, swelling beneath the skin, lightheadedness, vomiting, or those who required emergency care for their reaction—can get any flu vaccine. However, they should get the shot in a medical setting (such as a doctor’s office under the supervision of a health professional) to ensure that they can be treated in the rare case of a reaction. 
  • Anyone who has had a previous severe reaction to a flu vaccine should not get the flu vaccine at all. 

Egg-Free Flu Shots

The two egg-free versions are called Flublok Quadrivalent (approved for adults 18 and older) and Flucelvax Quadrivalent (now approved for anyone age 2 and older—formerly, was approved only for ages 4 and older).

Choosing the Best Flu Shot For You

Early in flu season, many pharmacies and doctors' offices will have several options for flu shots, including the ones for older adults, nasal spray versions, and those that are safe for people with egg allergies.

Lisa Doggett, MD, MPH

We have to remind people that COVID isn't the only virus to think about.

— Lisa Doggett, MD, MPH

Alex Brown, a spokesperson for Walgreens tells Verywell, that "if there's a specific flu shot your doctor has recommended or you prefer, call ahead to be sure it's in stock or to be referred to a nearby location with available supply."

Schaffner says that “getting a flu shot is the single best thing you can do to protect yourself,” but public health experts worry that as the COVID pandemic drags on, people might be experiencing “vaccine fatigue.”

"We have to remind people that COVID isn't the only virus to think about," Lisa Doggett, MD, MPH, a faculty member at the Dell Medical School of the University of Texas at Austin and a fellow with the American Academy of Family Medicine’s vaccine science fellowship, tells Verywell. "It's about to be flu season, too.”

According to the CDC, the side effects of the flu shot can include fever, muscle aches, pain, redness and swelling at the injection site, and fatigue.

“I understand people's fear and concern that the flu shot can sometimes cause side effects," says Doggett. “But usually, its effects are mild, and the shot does not, cannot, cause the flu.”  

Flu season runs from October to May in the U.S., with the peak occurring between December and February. Schaffner says that the best time to get the flu shot is before the end of October, which ensures that you are protected before cases start rising.

Plus, if you do get the flu but you have had the vaccine, your symptoms are likely to be milder than they would have been if you hadn't gotten the shot. Schaffner says that “while everyone 6 months and older should get a flu shot, it’s especially important for people with weaker immune systems including older adults and those with chronic illnesses.” 

“It’s a good idea to get that shot now,” says Grohskopf. "But if you find yourself in January or later not having had a flu vaccine, it’s not too late."

What This Means For You

Flu season runs from October to May in the U.S. The CDC advises that you get your flu shot by the end of October to ensure that you're protected. Vaccines may not prevent you from getting the flu, but they can make your symptoms milder if you do get sick and reduce your chances of severe illness, hospitalization, and death.

Wear your mask when you head out for your flu shot and remain socially distanced from others as much as possible. Consider calling ahead to make an appointment if your doctor or pharmacy schedules flu shots.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention (CDC). Burden of Influenza.

  2. Centers for Disease Control and Prevention (CDC). Interim Clinical Considerations for Use of COVID-19 Vaccines.

  3. Centers for Disease Control and Prevention. COVID-19: Quarantine and isolation.

  4. Centers for Disease Control and Prevention (CDC). How Influenza (Flu) Vaccines Are Made.

  5. Centers for Disease Control and Prevention (CDC). Flu Vaccine and People With Egg Allergies.

  6. Centers for Disease Control and Prevention (CDC). Flu Vaccine Safety Information.

By Fran Kritz
Fran Kritz is a freelance healthcare reporter with a focus on consumer health and health policy. She is a former staff writer for Forbes Magazine and U.S. News and World Report.