Will The Flu Shot Work This Year? Here’s Why Experts are Hopeful

A person is seen with a bandaid on their arm.
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  • A new report from the CDC finds that the flu shot was over 50% effective at preventing illness during the flu season in the southern hemisphere.
  • The report sheds light on what might happen during the upcoming flu season in the U.S.
  • The seasonal flu is linked to tens of thousands of deaths annually in the U.S.

As summer in the northern hemisphere slowly starts to turn to fall, countries in the southern hemisphere are ending their winter season, which is when the flu season hits.

With these changing seasons also comes data about the upcoming flu season in the U.S.

The seasonal flu vaccine is tweaked every year to best target the circulating viral strains. Data from flu vaccine in the southern hemisphere can shed light on what we can expect in the winter in the northern hemisphere.

Early signs point to the flu vaccine effectively preventing illness in the southern hemisphere. This means the vaccine being produced for the upcoming flu season in the U.S. could be effective.

Flu vaccine can cut severe flu symptoms

Officials from the Centers for Disease Control and Prevention (CDC) reported that initial data from South America shows that the flu vaccine helped to decrease severe disease.

The Centers for Disease Control and Prevention (CDC) reported, that “early, interim estimates, provided before the expected end of seasonal influenza virus circulation, suggest that vaccination substantially reduced the risk for severe influenza illnesses, underscoring the benefits of influenza vaccination.”

Based on data contributed by Argentina, Brazil, Chile, Paraguay, and Uruguay on 2,780 severe acute respiratory infection (SARI) patients hospitalized from March 27-July 9, 2023, the vaccine effectiveness associated with any influenza virus was 52%.

“This suggests that if the same strains of the virus continue to circulate, we could see the vaccine providing similar benefits against severe disease and hospitalizations,” said Hannah Newman, MPH, senior director of infection prevention at Northwell Lenox Hill Hospital. “While I don’t have a crystal ball, the success of this year’s flu vaccine in South America makes me hopeful that we will have a similar experience in the United States.”

While data from South America can be helpful indicator for North America, virus strains can also mutate slightly making the vaccine less effective during the U.S. winter season.

Dangers of the flu

Each year, the CDC estimates the burden of influenza in the U.S. Between 2010 and 2020, it estimates that the flu has resulted in 9 to 41 million illnesses, 140,000 to 710,000 hospitalizations, and 12,000 to 52,000 deaths annually. 

Symptoms of the flu can range from mild to severe, including the onset of fever, dry cough, headache, muscle and joint pain, sore throat, and runny nose.

Hospitalizations and deaths occur mostly in high-risk groups. 

People at higher risk, according to the World Health Organization, include pregnant women, very young children, older adults, and individuals with chronic medical conditions. These conditions include chronic cardiac, pulmonary, or kidney disease and people with suppressed immune systems.

Healthcare workers are also at high risk of developing the disease, given the increased exposure to patients with influenza.

How to protect against the flu

While there is no cure for the flu, it is possible to take measures to reduce the risk of exposure, as well as lessen symptoms. Getting a flu vaccine is one of the best measures we can take to help keep ourselves and those around us safe from severe illness.

“Influenza severity and peak of season can be difficult to predict, and the best preparation is to get vaccinated annually,” said Newman. “The CDC typically recommends getting your flu shot before the flu season begins. Getting vaccinated early allows your body time — usually about two weeks — to develop immunity before activity picks up so you’ll be well protected.”

She recommends September and October as good times to get vaccinated, ideally before the end of October.

“However,” she added, “it’s important to note that it’s never too late. Getting a flu shot later in the season is still beneficial to protect yourself and those around you.”

Flu shots are available to everyone and are free with most insurance or with government assistance. You can schedule an appointment with a primary care physician, pediatrician, etc. Pharmacies like CVS, Walgreens, and Rite Aid often offer walk-in flu shots without an appointment. Community health clinics often provide flu shots at low or no cost, as do flu shot clinics.

“Some employers offer flu shots to their employees at on-site clinics or through partnerships with healthcare providers,” said Newman. “Remember to check the specific location beforehand to verify availability, schedule, and any requirements.”

The website Vaccines.gov can help people find and schedule flu vaccines in their area.

Other ways to prevent the flu include cleaning and disinfecting frequently touched surfaces, getting plenty of sleep, staying active, managing stress, and maintaining a healthy diet.

If you feel any flu-like symptoms, it is best to stay away from other people. If your child experiences any flu-like symptoms, keeping them home from school is best.

The CDC also recommends these measures for reducing the risk of seasonal flu:

  • Avoid close contact with people who are sick
  • Cover your mouth and use a tissue when coughing or sneezing
  • Wash your hands often
  • Avoid touching your eyes, nose, or mouth


A new report from the CDC finds that the flu vaccine was over 50% effective at preventing illness in the southern hemisphere. That may be a predictor that the vaccines being developed for this upcoming flu season in the U.S. will be effective at stopping infections.

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