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Medical experts are raising concerns that the current spike of COVID-19 cases could collide with the fall flu season, placing an even greater strain on our health care system. Pixels Effect / Getty Images
  • Cases of the flu were “unusally low” during the 2020-2021 season.
  • However, the easing of COVID-19 restrictions could lead to a resurgence in cases.
  • When coupled with the rising number of COVID-19 cases, experts warn we could be facing a “twindemic.”
  • Vaccinations will play a key role in controlling both diseases.
  • Mask-wearing, handwashing, and social distancing can also play an important role.

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 Some information may be out of date.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.

Experts are warning that a resurgence in the flu, coupled with the rising number of COVID-19 cases, could cause a “twindemic” this fall, adding a greater burden to our healthcare system.

The Centers for Disease Control and Prevention (CDC) reports that cases of the flu were “unusually low” during the 2020-2021 season.

In fact, between Sept. 28, 2020, and May 22, 2021, only 0.2 percent of the 818,939 samples tested in U.S. laboratories were positive for the virus.

However, the flu is likely to make a comeback to pre-pandemic levels this year as many COVID-19 restrictions such as masks and social distancing have been lifted in many areas.

In addition, the CDC reports that we are seeing a rapidly rising number of COVID-19 cases as we prepare to enter fall.

On Sept. 6, new cases were reported to be 47,728, while the 7-day moving average of cases was 127,100.

By comparison, on June 20 of this year, there were 9,014 new cases with a reported 7-day moving average of 11,729 cases.

Though it has been popular on social media to suggest that flu cases were down last year because they were being misreported as COVID-19, experts say the forces at play are much less sinister.

“Because many of us were wearing masks, practicing good hand hygiene, and social distancing, the flu season was mild last year,” said Karen L. Edwards, PhD, professor and chair of the Department of Epidemiology and Biostatistics at the University of California, Irvine.

Basically, the steps that help prevent the spread of COVID-19 can also help prevent the spread of other respiratory illnesses like the flu, she explained.

Dr. S. Wesley Long, a researcher at Houston Methodist Hospital in Houston, agrees.

“It was most likely the global lockdowns, combined with masking and other social distancing measures and reduced international travel,” he said.

“This led to a historically low flu season in the Southern Hemisphere followed by a historically light flu season in the Northern Hemisphere.”

Long said now that lockdowns, mask mandates, and social distancing measures have been relaxed in many areas, we have seen an upward surge in non-COVID-19 respiratory viruses, such as the common cold and respiratory syncytial virus (RSV).

He added that it is likely we will also see an increase in flu cases, although it is difficult to predict exactly what the flu season will look like.

In addition, we are experiencing a fourth wave of COVID-19 cases due to the Delta variant, he said, which may be cresting in some parts of the country.

“I think this wave will have a long tail, and the size and shape of the next wave is really dependent on vaccination rates, masking, social distancing, and potential further evolution of the SARS-CoV-2 virus,” Long said.

Edwards and Long both emphasized the importance that vaccinations will play in controlling any potential flu/COVID-19 twindemic.

People should get vaccinated for both flu and COVID-19 if they are able, Edwards said. They are caused by different viruses, so a different vaccination is needed for each of them.

Although the flu was mild last year due to mask-wearing, hand hygiene, and other measures we were taking against COVID-19, it is possible that our natural immunity to the flu will be lower this year if we don’t get a flu vaccination, said Edwards.

Long further added that he feels vaccines are “key” in preventing a twindemic this fall.

He said it is very difficult to predict exactly what will happen, but it will depend on both the rate of flu vaccination and the underlying behavior of the flu this season.

“I think it is safe to say we are going to see more cases of influenza this year than 2020,” he said.

However, he does feel that a twindemic can be prevented if everyone does their part, including getting vaccinated.

In addition to getting vaccinated, Edwards said that it is important to continue with the protective measures that we employed last year against COVID-19.

Masking, handwashing, and social distancing can all go a long way in preventing the spread of both the flu and coronavirus.

Long added that it is important to stay home if you are sick and get tested if you are having symptoms.

If you know whether you have the flu or COVID-19, it helps you to avoid transmitting it to others.