Are you stuffy? Achy? Feverish?

For most people, these classic flu symptoms typically mean a few days of rest, fluids, and maybe fever-reducing medications. In fact, the flu has been around for so long, that many of us don’t think much about it. But, despite our relaxed attitude, the flu continues to be responsible for between 140,000 – 810,000 hospitalizations and up to 61,000 deaths a year.

This year, the situation is even more complicated.  With a pandemic that has already killed over 200,00 Americans, many people are feeling a lot of anxiety about the dangerous overlap of COVID and flu season.  While they might seem similar, there are some key differences between the flu and COVID which we need to understand in order to best protect ourselves from both potentially life-threatening illnesses.

Symptoms of the flu vs COVID-19

While symptoms of the flu and COVID are very similar, the CDC notes some important differences:

Flu symptoms:

  • fever or feeling feverish/chills
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue (tiredness)
  • some people may have vomiting and diarrhea, though this is more common in children than adults.

COVID symptoms:

  • Fever or chills
  • Cough
  • Shortness of breath or difficulty breathing
  • Fatigue
  • Muscle or body aches
  • Headache
  • New loss of taste or smell
  • Sore throat
  • Congestion or runny nose
  • Nausea or vomiting
  • Diarrhea

A significant difference between the two is that flu symptoms generally develop 1 to 4 days after the infection, while COVID-19 symptoms can take as long as 14 days to show up, lengthening the time that a person without symptoms can spread the virus. Another important difference is that the flu can usually only be passed one day before symptoms are evident, while COVID-19 can be transmitted 2-3 days before the infected person is symptomatic.

Who is most at risk for the flu vs. COVID-19?

While both the flu and COVID can potentially cause complications in anyone, there do seem to be some differences in which part of the population is most vulnerable. Both viruses are dangerous to the elderly, people with certain underlying medical conditions, and pregnant women. But while young children are at high risk for flu complications, they are generally not as affected by COVID.

How do the spread of the flu and COVID-19 differ?

The good news is that, despite their differences, the flu and COVID both seem to be passed in similar ways. Experts believe that both viruses are primarily spread through the large droplets released when an infected person sneezes, coughs, or speaks. If another person is standing close enough so that those droplets can land in their nose or mouth, they can become infected. There is also a small chance that a person could contract both illnesses by touching a surface where the droplets have landed.

While less common, there is increasing evidence that both the flu and COVID can also be spread by aerosols.  This means that the viruses are able to travel in tiny airborne droplets that are released when an infected person breathes. Because aerosols are able to travel further and linger longer in the air, preventing the spread of viruses this way can be more complicated.

How can we limit the transmission of the flu vs. COVID-19?

The best way to reduce your risk of getting the flu is by getting a yearly flu vaccine.  Unfortunately, there are no vaccines available yet for COVID-19. Scientists hope to have a working vaccine ready to distribute sometime in the near future.

In the meantime, mask-wearing and social distancing are still the best ways to prevent the spread of COVID-19. These policies which were instituted in response to the pandemic may also help to make this a milder flu season.

Another way of minimizing the spread of both illnesses is to make sure your indoor air is clean.  This is especially important as the weather gets colder and more gatherings move indoors.

How to keep your indoor air virus-free

Open windows: Opening windows has long been known to help reduce the transmission of various illnesses.  In fact, A 2019 study in the journal BMJ Infectious Diseases found that windows and other sources of natural ventilation can reduce the transmission of tuberculosis by 72%. The reason is that when outdoor air flows freely through your home, it helps dilute the concentration of infectious particles. Keeping windows open is one of the cheapest, most effective ways to reduce transmission of both COVID and the flu.

Use an air purifier with a True HEPA filter: Using a high-quality air purifier with a True HEPA filter to clean the indoor air gets rid of 99% of viruses that are larger than .3 microns in size… which means it eliminates both COVID and the flu. HEPA filters work so well that the CDC recommends using them in office spaces and other indoor environments to reduce the rate of infection.

Use humidifiers: Stephanie Taylor, an infection control consultant at Harvard Medical School, conducted multiple studies showing that an indoor humidity level of between 40% to 60% has the potential to drastically reduce infection rates of many illnesses. While the results are not yet conclusive, by eliminating almost every factor, her tests showed a strong correlation between indoor infection rates and humidity. This means that humidifiers can be an important tool in fighting the spread of both the flu and COVID.

How do you heal from the flu vs COVID-19?

Flu: Most people with the flu have mild symptoms and are recommended to heal at home by resting, getting enough fluids, and using over-the-counter medicine.  However, if you have severe flu symptoms or are in a high-risk group, it is best to consult your health care provider.  There are a number of anti-viral medications that have been proven to lessen the length and severity of the flu.

COVID-19: Because the illness is so new, treatment is still evolving.  While most cases of COVID-19 are mild, more severe cases require urgent medical care. The National Institutes of Health (NIH) has developed guidance on treatment of COVID-19, which will be regularly updated as new evidence on treatment options emerges. So far, remdesivir is the only medication that is being approved as a treatment due to an Emergency Use Authorization by the FDA.

How long do people remain contagious from the flu vs COVID-19?

Flu: Most people are most contagious during the initial 3-4 days of their illness, but some may remain contagious for about 7 days.

COVID: People with COVID remain contagious for at least 10 days after symptoms appear.