During flu season in the United States—from October to May—there isn’t a precise number of how many people die from the flu annually. However, the CDC estimated approximately 20,000 flu-related deaths during the 2019–2020 flu season.

Because the flu is not a reportable disease in most states, experts rely on estimates based on lab-confirmed, flu-associated hospitalization rates. Many people who get the flu never seek medical care, which also affects accurate tracking.

During the 2019–2020 season, there were an estimated 35 million flu-related illnesses, which included 16 million medical visits and 380,000 hospitalizations. In comparison, during the height of the COVID-19 pandemic, flu activity dropped dramatically—only 748 flu-related deaths were reported during the 2020–2021 flu season.

Average Annual Flu Deaths

According to CDC data from 2010 to 2020, annual flu deaths in the U.S. ranged from 12,000 to 52,000. During the same period, flu cases ranged from 9 million to 41 million per year, with hospitalizations between 140,000 and 710,000. Globally, the World Health Organization estimates that 290,000 to 650,000 people die from flu-related complications each year.

These numbers vary widely due to the constantly changing nature of flu viruses. There are hundreds of strains, and new variants can emerge through gradual mutations or sudden genetic shifts. Sometimes, a flu virus jumps from animals to humans, as was the case with the H1N1 virus that originated in swine and led to a global outbreak.

The dominant flu strain varies each year. Some strains may be more severe, contributing to more hospitalizations and deaths in certain seasons.

Predicting Flu Severity

To estimate the severity of upcoming flu seasons, the CDC uses key indicators known as intensity threshold (IT) values. These include:

  • Hospitalization rates due to flu

  • Percentage of outpatient visits for flu-like symptoms

  • Percentage of deaths from flu or pneumonia

This data helps with forecasting and preparation, including resource planning for hospitals, vaccination campaigns, and public health interventions.

During the COVID-19 pandemic, the low flu case count may have reduced natural immunity in the population. As a result, experts anticipated a more severe 2022–2023 flu season due to both relaxed COVID precautions and weakened flu immunity.

From October 2022 to April 2023, the CDC estimated between 27 million and 54 million flu cases—potentially more than the 2019–2020 season.

The Role of Vaccines

The number of flu-related deaths in a given season also depends on how accurately scientists predict the circulating strains and how many people receive the flu vaccine. Countries like Australia, which experience winter while the U.S. is in summer, help guide flu vaccine development for the Northern Hemisphere.

When no flu season occurs in those countries—as in 2021—it can be harder to determine which strains should be included in the vaccine. Still, each vaccine provides immunity against multiple flu strains and is a critical tool in preventing severe illness.

How To Protect Yourself

The best way to protect yourself from the flu is to get vaccinated annually. The CDC recommends that everyone aged 6 months and older get a flu shot each year.

People at higher risk for flu complications include:

  • Adults over age 65

  • Children under 5

  • People with chronic conditions (e.g., asthma, heart disease, diabetes)

  • Pregnant individuals

While research is still ongoing about whether high-dose vaccines are more effective for people with certain medical conditions, it’s best to consult a healthcare provider to determine the most appropriate option.

Other Prevention Methods

In addition to vaccines, the same measures that help prevent the spread of COVID-19 also protect against the flu:

  • Avoiding crowded or enclosed places

  • Washing hands regularly with soap and water

  • Wearing masks during cold and flu season

  • Practicing social distancing

  • Staying home when sick

Adopting these habits during winter months may significantly reduce flu-related deaths, similar to how flu numbers declined during the pandemic.

A Quick Review

Flu-related deaths vary year by year, ranging from tens of thousands to hundreds of thousands globally. These fluctuations depend on which flu strains are circulating, population immunity, and vaccination rates. Public health experts use global and historical data to help predict flu severity and prepare vaccines. Getting vaccinated, staying home when sick, and practicing good hygiene are some of the most effective ways to protect yourself and those around you.