While COVID-19 has been the main illness on most people’s minds for the past year and a half, we’re now entering flu season. Last year’s flu season was practically non-existent, but public health officials anticipate that this year could be a doozy. And it seems it’s already started.

Data from the Walgreens flu index shows that flu activity is up 23% over last year right now, with some of the biggest increases in Las Vegas, several areas in Texas, and some southern states. Overall case numbers remain low, though: Data from the Centers for Disease Control and Prevention (CDC) show that just 42 people were diagnosed with flu the week ending October 9.

It’s not shocking that flu activity would pick up this time of year—influenza cases usually start to increase in October before peaking in December and February, according to the CDC. But an almost 25% jump this early in the season seems like a lot.

What does this mean for this year’s flu season? Here’s what you need to know.

What is the flu, again?

It’s probably been a minute since you’ve thought about the flu. The flu is a contagious respiratory illness that’s caused by influenza viruses that infect the nose, throat, and sometimes the lungs, the CDC explains. It can cause anything from mild sickness to severe illness, and it can even kill people.

Flu viruses usually spread from tiny droplets that are made when infected people cough, sneeze, or talk, the CDC says. Those droplets can land in your mouth or nose and make you sick. In some cases, you may also pick up the flu by touching a surface or object that has the virus on it and then touching your own mouth, nose, or eyes.

The flu usually comes on suddenly and can cause the following symptoms, per the CDC:

  • fever or feeling feverish/chills
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue
  • Vomiting and diarrhea (more common in kids than adults)

What was last year’s flu season like?

The 2020-2021 flu season had incredibly low numbers. Between October 3, 2020 and July 24, 2021, the CDC saw only 2,136 positive flu tests out of 1.3 million specimens tested by laboratories, according to official data published by JAMA. The data show that there were 736 deaths from the flu, too. (By comparison, there were an estimated 35 million flu-related illnesses and 20,000 flu-related deaths during the 2019-2020 influenza season, per CDC data).

“Last year, we had no flu, essentially,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine.

What will this year’s flu season be like?

It’s hard to predict but Rochelle Walensky, M.D., M.P.H., director of the CDC warned during a press briefing in early October that this flu season may be intense.

"Last year there were very few flu cases, largely because of masking and physical distancing and other prevention measures put in place for the COVID-19 pandemic," Dr. Walensky said. "With modest flu virus activity since March of 2020, CDC's flu experts are concerned that reduced population-level immunity to the seasonal flu could place us at risk for a potentially severe flu season this year."

Still, Dr. Schaffner says, “it’s very early in the flu season. We do expect there to be influenza this season, but we’re not sure how much.” Dr. Schaffner points out that the factors that dramatically lowered the level of the flu circulating last year—masking, social distancing, and doing remote work and schooling—are “now reversed.” As a result, he says, “there are now many opportunities for flu to be transmitted.”

Infectious disease expert David Cennimo, M.D., an assistant professor of medicine at Rutgers New Jersey Medical School, notes that “it’s not difficult to be up 25% when cases were basically zero last year.” But, he adds, the numbers “are a little surprising in that it’s kind of early to be seeing this level of flu activity. This is earlier than expected.”

How to protect yourself from the flu

The best thing you can do is to get vaccinated against the flu and encourage the other members of your household to do the same, Dr. Schaffner says. “It’s tough because there’s real vaccine fatigue out there,” he says. “People don’t even want to think about it. It’s almost as if we have to reintroduce everyone to flu because they’ve been so preoccupied with COVID.”

But, Dr. Schaffner says, “flu will be back this year—get your vaccine.”

Anyone can get the flu, but some people are at higher risk for complications than others. According to the CDC, those include:

  • Adults 65 years and older
  • Children younger than 2 years old
  • People who are obese with a body mass index [BMI] of 40 or higher
  • People younger than 19 years old on long-term aspirin- or salicylate-containing medications.
  • People with a weakened immune system due to disease (such as people with HIV or AIDS, or some cancers such as leukemia) or medications (such as those receiving chemotherapy or radiation treatment for cancer, or persons with chronic conditions requiring chronic corticosteroids or other drugs that suppress the immune system)
  • People who have had a stroke

The following health conditions can also put you at a higher risk of flu complications, the CDC says:

  • Asthma
  • Neurologic and neurodevelopment conditions
  • Blood disorders (like sickle cell disease)
  • Chronic lung disease (like chronic obstructive pulmonary disease [COPD] and cystic fibrosis)
  • Endocrine disorders (like diabetes mellitus)
  • Heart disease (like congenital heart disease, congestive heart failure, and coronary artery disease)
  • Kidney diseases
  • Liver disorders
  • Metabolic disorders (like inherited metabolic disorders and mitochondrial disorders)
  • Pregnancy

If you fall into a higher risk category, Dr. Schaffner recommends taking additional steps to protect yourself. That includes wearing a mask in public, washing your hands well, and doing your best to practice social distancing—in addition to getting vaccinated.

“We did those things last year for COVID and flu basically went away,” Dr. Cennimo says. “If you continue to do those things, you will be relatively safe from flu as well.”

Headshot of Korin Miller
Korin Miller
Korin Miller is a freelance writer specializing in general wellness, sexual health and relationships, and lifestyle trends, with work appearing in Men’s Health, Women’s Health, Self, Glamour, and more. She has a master’s degree from American University, lives by the beach, and hopes to own a teacup pig and taco truck one day.