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Will There Be a Flu/COVID-19 Twindemic?

September 15, 2021

As fall approaches, so does the flu season and concern about a so-called twindemic. This term was coined to describe having both influenza viruses and the COVID-19 virus circulating at the same time. Although the flu can spread any time, it is most common during the fall and winter, when we spend more time indoors. Last year, experts were worried about a twindemic during the fall. This didn’t happen because using masks and social distancing to prevent COVID-19 spread prevented the flu too. But now there is growing concern again. The introduction of the COVID-19 vaccines is leading to the end of mask and isolation mandates in many places, and people are returning to social gatherings and larger group activities.

What is influenza?

Influenza is a serious, contagious respiratory virus that can be fatal. The number of people affected varies quite a bit from year to year, depending on the strength of the dominant flu viruses. There were 22,000 flu-related deaths in the United States during the 2019-2020 season. An estimated 61,000 people in the U.S. died from the flu during the 2017-2018 flu season. This is more than the number of people who fit in Yankee Stadium.

Influenza spreads through droplets in the air and by touch. If someone with the virus coughs without covering their mouth and nose, the airborne virus can reach another person close by, who can then breathe it in. Or, if the person with the virus touches their nose or mouth and then touches an object like a doorknob, they leave the virus behind for someone else to pick up when they touch that same object.

Washing hands, social distancing, and vaccines – infection prevention techniques to prevent the spread of COVID-19 – are also what people need to do to avoid catching the flu. But now as COVID-19 restrictions and protections are ending in many places, the influenza virus has room to grow.

The concern about a twindemic

Every year, millions of people in the U.S. get the flu. Most feel better after a week or so of feeling quite ill, although full recovery can take several more weeks. However, thousands of people get sick enough to need hospital care. During the 2017-2018 season, there were an estimated 810,000 hospitalizations; in 2019-2020, there were 400,000.

Currently, many ICUs across the country are filled with COVID-19 patients, leaving little room and resources for those who may get the flu, and become equally ill. This situation also affects people with serious medical emergencies like a heart attack or stroke. As the ICUs fill, patients have nowhere to go for the high level of care they need. In August, a 46-year-old man with gallstone pancreatitis died because his doctors could not find an ICU bed for him. By the time they airlifted the patient to the one available bed in Houston, Texas, it was too late. A twindemic would make this situation even worse.

Another important issue to consider is that having one infection does not mean you cannot get the other. They are two separate illnesses. It is possible to have both the flu and COVID-19 – one infection after the other or even at the same time. If someone recovering from the flu contracts COVID-19, or the other way around, they may not be strong enough to fight the second virus.

To prevent overwhelming the medical system even more, it is essential that people take steps to reduce their risk of getting and spreading the flu, as well as other contagious illnesses.

Determining the difference between the flu and COVID-19 during a twindemic

Most initial COVID-19 symptoms are similar to influenza symptoms, making it harder to tell them apart, especially during a twindemic. They include:

  • Fever, chills
  • Coughing, shortness of breath
  • Sore throat
  • Runny nose
  • Fatigue
  • Muscle aches
  • Headache
  • Vomiting and diarrhea (children mostly)

At this point, the only way to tell the difference between the two illnesses is by using flu and COVID-19 tests. There is no cure for either infection, but treatment may help relieve symptoms and prevent serious illness or death.

COVID-19 can also cause loss of taste and smell, blood clots, and multisystem inflammation syndrome, called MIS-C when it affects children and MIS-A when it affects adults. The virus can also cause “long COVID”, which can last weeks or months following the initial illness.

Both infections also can cause similar complications, including:

  • Secondary infections, such as pneumonia
  • Respiratory failure
  • Viral sepsis

A third virus in the mix, affects mostly children

Another type of respiratory virus, called RSV (respiratory syncytial virus) is an added concern in the medical community. This disease usually affects children and, like the flu, is more common during the fall and winter. However, this year children are contracting the virus earlier than ever. According to an article published by the Associated Press, doctors are not used to this: “I’ve never seen anything like this before,” Kate Dutkiewicz, MD, said in the article. ‘’I’ve never seen cases in July, or close to July.’’ Dutkiewicz is the medical director at Beacon Children’s Hospital in South Bend, Indiana.

The Centers for Disease Control and Prevention (CDC) is concerned. Because there was little circulation of RSV last year, children were not exposed and able to develop any immunity: “Due to reduced circulation of RSV during the winter months of 2020–2021, older infants and toddlers might now be at increased risk of severe RSV-associated illness since they have likely not had typical levels of exposure to RSV during the past 15 months.”

There is no RSV vaccine yet.

Preventing infections

The annual influenza vaccine programs will start rolling out shortly. The first batch of vaccines were approved by the FDA in mid-August. They are approved for adults and children over age 6 months. As with the COVID-19 vaccine, the flu vaccine is not 100% effective at preventing illness, but it can go a long way in helping prevent a twindemic. The vaccine does significantly reduce the risk of serious illness and death.

Experts are recommending that adults not wait for their vaccine as they might normally do, but to get it before the end of October. The American Academy of Pediatrics also recommends that this year, children receive their flu vaccine earlier than usual:

All influenza immunization doses should be completed by the end of October, if possible. Children ages 6 months through 8 years who are receiving flu vaccine for the first time, who have had only one dose ever prior to July 1, 2021, or whose vaccination status is unknown should be vaccinated as soon as vaccines become available so they can receive two doses four weeks apart by the end of October.”

Viruses are here to stay

Viruses and other microbes will continue to circulate and make people ill, twindemic or not. Given that any kind of infection can cause sepsis, it is important to continue maintaining infection prevention practices: isolating yourself if you are sick so you can’t pass on the infection, washing your hands frequently, and getting all recommended vaccines. In the case of COVID-19, it can also mean wearing a mask.

If you do show signs of an infection, watch for signs of sepsis. If you suspect sepsis, seek medical help immediately. Sepsis is a medical emergency.