Influenza (Flu) and Covid-19 are both contagious respiratory illnesses, so telling them apart can sometimes be a challenge. The two are similar and different in many ways, but often times it is difficult to discern which illness you may have through symptoms alone so testing is often needed to confirm. Below we have listed a few key topics and laid out the similarities and differences between the flu and COVID-19, which we hope will help you determine what you may be suffering from or how long you may be able to spread each virus.
Signs and Symptoms:
Both COVID-19 and the flu have varying degrees of signs, ranging from no symptoms at all to severe symptoms. Common symptoms then two share are included here:
- Fever or chills
- Shortness of breath or difficulty breathing
- Sore throat
- Runny or stuffy nose
- Muscle pain or body aches
- Vomiting and diarrhea
- Change in or loss of taste or smell – This can be seen in both illnesses but is more commonly seen in COVID-19. Loss of taste or smell is often times one way to discern whether you have COVID-19 or the flu, but testing will be needed to confirm.
As we discussed with the symptoms above, the viruses seem to have many similarities in how they affect the body. However, both viruses also produce a wide range of complications which vary on a case by case basis. Below we have listed some of the similarities and differences in the complications these viruses produce.
- Respiratory failure
- Acute respiratory distress syndrome (Fluid in the lungs)
- Cardiac injury
- Multiple-organ failure
- Worsening of chronic medical conditions
- Inflammation of the heart, brain or muscle tissues
- Secondary infections
- Flu complications: Most people with the flu will recover on their own within a few days or up to two weeks, but some will experience severe complications like we listed above and require hospitalization. A key difference between the two viruses is that secondary bacterial infections are more common with influenza than with COVID-19.
- COVID-19 complications: In addition to what was mentioned above, blood clots in the veins and arteries of the lungs, heart, legs or brain have been a complication associated with COVID-19.
How long symptoms appear after exposure and infection:
For both COVID-19 and flu, it’s possible to spread the virus for at least 1 day before you have experienced any symptoms, which is why sometimes it is difficult to control the spread. However, if a person has COVID-19, they could be contagious for a longer period of time then someone who has the flu, which is the key difference. We have broken down the specific illness individually down below.
- Flu: Like noted above, most people with the flu are contagious for about 1 day prior to showing any symptoms. Older children and adults are often most contagious during the initial 3-4 days of the illness but may remain contiguous for up to 7 days after exposure.
- COVID-19: For this illness, it’s possible to spread the virus for about 2 days before experiencing any symptoms and you can remain contagious for at least 10 days after signs first appeared. COVID-19 is also difficult to judge because even if someone is asymptomatic or their symptoms go away, they too can remain contagious for at least 10 days. People who have been hospitalized with severe illness or people with weakened immune systems can be contagious for 20 days or longer.
How it spreads:
- Similarities: Both COVID-19 and flu can be spread from person-to-person who are in close contact to one another or within roughly 6 feet. Both viruses are spread mainly by large and small particles expelled into the air when people who are infected cough, sneeze, or talk. These particles land in the mouths or noses of people nearby and are inhaled into the body through the lungs.
- Some environments, such as certain indoor settings with poor ventilation, will allow for particles to spread further than 6 feet, putting those in the environment at an even greater risk of getting sick.
- Although inhalation of the virus is the most common, it is also possible to get infected through direct contact, such as shaking hands or touching an infected surface that has the virus on it.
- As mentioned above, both viruses can be spread before any initial symptoms have been shown, so it’s recommended to take as many protective measures as possible to limit your risk of becoming infected.
- Differences: While they are spread in a similar fashion, COVID-19 is generally more contagious than the flu viruses. Also, COVID-19 has been observed to have produced more super spreading events than the flu has produced. This means the COVID-19 viruses can spread very quickly and can make it very difficult to control if proper precautions are not made.