Influenza (commonly known as the flu) and COVID-19 are both highly contagious respiratory illnesses and can easily spread to others. Although the symptoms of COVID-19 and the flu can look similar, the two illnesses are caused by different viruses.
COVID-19 is caused by the 2019 coronavirus, also known as SARS-CoV-2.
Flu is caused by any of several different types and strains of influenza viruses.
- Both illnesses can cause fever, cough, body aches, and sometimes vomiting and diarrhea (especially in children).
- Both can result in pneumonia.
- Both flu and COVID-19 can be mild or severe, or even fatal in rare cases.
COVID-19 can sometimes cause a person to suddenly lose their sense of smell (anosmia) or taste (ageusia).
By contrast, flu does not typically affect a person’s sense of smell or taste.
Shortness of breath is quite common with COVID-19 while it is a rare symptom of the flu.
Many people infected with the coronavirus do not feel sick or have any symptoms at all, but they can still transmit the virus to other people. By contrast, most people infected with flu tend to be symptomatic.
So how long does it take for symptoms to appear after exposure and infection?
If a person has COVID-19, it could take them longer to develop symptoms than if they had flu.
Typically, a person develops symptoms anywhere from 1 to 4 days after infection.
Typically, a person develops symptoms 5 days after being infected, but symptoms can appear as early as 2 days after infection or as late as 14 days after infection, and the time range can vary.
How do they spread?
- Both the flu and COVID-19 spread in similar ways. Droplets or smaller virus particles from a sick person can transmit the virus to other people nearby. The smallest particles may linger in the air, and another person can inhale them and become infected.
- However, COVID-19 seems to spread more easily than flu and causes more serious illnesses in some people. Another important difference is there is a vaccine to protect against flu. There is currently no vaccine to prevent COVID-19, though research is ongoing.
- Again, it’s important to note that people infected with the coronavirus or the flu may not realize they are sick for several days and, during that time, can unknowingly spread the disease to others before they even feel sick.
What are some complications caused by these illnesses?
Both COVID-19 and flu can result in complications, including:
- Respiratory failure requiring supplemental oxygen support
- Acute respiratory distress syndrome (i.e. fluid in lungs), which usually lands people in ICU
- Heart problems
- Multiple-organ failure (respiratory failure, kidney failure, shock) commonly known as sepsis
- Secondary bacterial infections
Additional complications associated with COVID-19 can include:
- Blood clots in the veins and arteries of the lungs, heart, legs or brain
COVID-19 close to 3%. FLU causes <1% of deaths among the people infected.
Testing Options available:
Influenza or the FLU:
First of all, influenza virus testing is not required to make a clinical diagnosis of influenza in patients with suspected influenza, particularly during periods of increased cases. However, influenza virus testing can inform clinical management when these results may influence decisions such as:
- initiating antiviral treatment
- performing other diagnostic testing
- implementing infection prevention and control measures for influenza
Influenza virus testing is recommended for all patients with suspected influenza who are being admitted to the hospital. Furthermore, during a respiratory illness outbreak in a closed setting (such as long-term care facility or nursing homes), testing for influenza virus infection can be very helpful in determining if influenza is the cause of the outbreak.
There are several diagnostic tests available for detection of influenza viruses in respiratory specimens.
For the purposes of this forum, I would just like to mention the Rapid Influenza Diagnostic tests, which are readily available in outpatient settings, such as the doctors’ office and urgent care clinics. They can detect influenza viral antigens in 10-15 minutes with a reasonable accuracy.
Since COVID-19 is a new disease, information about the tests to detect the disease with high accuracy is still evolving. But here’s what we know now about tests that are currently available to the public:
Diagnostic tests for current COVID-19 infection:
If you want to know if you are currently infected with the COVID-19 virus, there are TWO types of tests:
- Molecular tests
- Antigen tests
Molecular tests (also called PCR tests)
How is it done? Nasal swabs, throat swabs, and tests of saliva or other bodily fluids.
You can get it done at a hospital or in a medical office.
What does the test look for? Molecular tests look for genetic material that comes only from the virus.
How long does it take to get results? It depends on lab capacity. Results may be ready the same day, but usually take at least a day or two. Throughout the pandemic, especially lately, delayed turnaround times of up to a week or two have been reported in many places.
A molecular test using a deep nasal swab is usually the best option, because it will have fewer false negative results than other diagnostic tests or samples from throat swabs or saliva. People who are in the hospital, though, may have other types of samples taken.
It is also performed using a nasal or throat swab.
It can be obtained at a hospital or doctor’s office or even at home (Quest Diagnostics, costs around $130).
If the test is negative, it should be confirmed by the PCR test which is more specific for COVID-19
This is a third type of test that requires a sample of blood. It checks for antibodies in the blood. However, it does not differentiate between the present and past infection.
Moreover, having an antibody test too early can lead to false negative results. That’s because it takes a week or two after infection for your immune system to produce antibodies.
The bottom line:
Unfortunately, getting a test for COVID-19 can be confusing because the options are changing and tests from many companies are being marketed. Despite the current limitations of testing, we’re lucky to have reasonably accurate tests available so early in the course of a newly identified virus.
Getting a flu vaccine this year may be more important than ever to reduce stress on healthcare facilities that are already busy with COVID-19 care.
Emergency care available
If you are having trouble breathing, have chest pain, inability to stay awake, confusion or blue lips or face, come to Medco ER & Urgent Care immediately for help.
If you suspect you have COVID-19, come in for evaluation.
If you think you have COVID-19 and you have a preexisting, chronic medical condition such as diabetes, heart disease, high blood pressure, cancer, kidney disease, asthma, obesity, lung disease or if you are pregnant, come in for evaluation.
- Plano: 3960 Legacy Drive on the corner of Legacy and Coit Road.
Call us @ 469-392-4000.
– Dr. Tariq Vora, Medco ER & Urgent Care