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Sneezing is usually a symptom of the common cold, but it can be an indicator of other illnesses. raquel arocena torres/Getty Images
  • Many health officials expect influenza and cold cases to increase this fall and winter as COVID-19 safety protocols are eased.
  • Experts note many symptoms for the flu and COVID-19 are similar, including fever and body aches. However, breathing difficulty is more common with COVID-19.
  • Health officials say that if you’re not feeling well, you should isolate, hydrate, and get tested.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date. Visit our coronavirus hub and follow our live updates page for the most recent information on the COVID-19 pandemic.

Remember the flu?

Seasonal influenza cases were rare last winter and experts credit COVID-19-related physical and social distancing and mask-wearing for keeping rates low.

With COVID-19 restrictions easing, however, the flu is expected to make a comeback.

That could make it harder to tell whether that irritating cough, congestion, or fever is only a cold, the flu, or something worse.

“Droplets spread viruses like the flu, COVID-19, or things like RSV (respiratory syncytial virus) in the air,” Dr. Phil Mitchell, an emergency room physician and chief medical officer at DispatchHealth, told Healthline. “The steps we took to avoid the spread of COVID-19 with masks, social distancing, good hand hygiene is universal prevention for all respiratory viruses. Because we practiced unprecedented levels of protection, resulting in almost no flu, some health experts speculate we lack some natural immunity, and flu may come back this fall with a vengeance.”

During the 2019-2020 influenza season, an estimated 38 million people in the United States became ill with the flu, according to the Centers for Disease Control and Prevention (CDC).

Between September 27, 2020, and April 24, 2021 — a span that included the peak of the COVID-19 pandemic — only 2,038 flu cases were reported to the CDC.

But some research suggests that diseases such as the flu are poised to return in 2021-2022.

For example, the CDC recently reported that cases of RSV, which declined sharply after April 2020, are climbing back up again in the southern United States, where COVID-19 precautions have largely been lifted.

RSV is the most common cause of bronchitis and pneumonia among infants and is especially dangerous among young children and older adults.

“After a worldwide drop in influenza cases and the lowest rate on record in the United States during the pandemic, we should all expect to see more flu in the coming fall and winter,” Dr. David Cutler, a family medicine physician at Providence Saint John’s Health Center in Santa Monica, California, told Healthline. “So, it will be very important for everyone to get their flu vaccines. And since there was so little flu last year, we really don’t know the impact that COVID and influenza might have together. So, it remains critically important that as many people as possible get immunized against COVID as well.”

RSV causes flu-like symptoms, and many of the symptoms of the flu are likewise similar to those caused by COVID-19 infections, including fever, cough, body aches, sore throat, fatigue, and congestion.

The delta variant of COVID-19 may present with symptoms even more commonly associated with the flu or common cold, including headache, sore throat, and runny nose — which were not typical among people with previous strains of the novel coronavirus.

Symptoms that seem fairly unique to COVID-19 are breathing difficulties and loss of taste or smell, although not every person who develops COVID-19 experiences these symptoms.

Fever is rarely a symptom of the common cold but is common among people with COVID-19, flu, and RSV.

“Symptoms of the flu and COVID are almost identical, which is why testing is critical. It’s the only way you’ll know,” said Mitchell, whose company provides at-home testing for COVID-19, the flu, and other illnesses. “It is possible to have both COVID-19 and the flu.”

“My advice, if you start feeling run-down and not well [you should] isolate, hydrate, and get tested,” he added.

Typical symptoms of COVID-19 include:

  • fever or chills
  • cough
  • shortness of breath or difficulty breathing
  • fatigue
  • muscle or body aches
  • headache
  • loss of taste or smell
  • sore throat
  • congestion or runny nose
  • nausea or vomiting
  • diarrhea

Typical symptoms of influenza (the seasonal flu) include:

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

Typical symptoms of the common cold include:

  • sore throat
  • runny nose
  • coughing
  • sneezing
  • headaches
  • body aches

Typical symptoms of RSV include:

  • runny nose
  • decrease in appetite
  • coughing
  • sneezing
  • fever
  • wheezing