Flu, common cold or COVID?

Gino Bottino, MD


Even with COVID-19 soaring, we need to remember that winter is also cold and flu season.

In the United States, more days of work (and probably play) are lost to colds and flu than any other illness, and mortality remains high.

Colds and allergies are frequently confused, and now it’s hard to tell the difference between these illnesses and COVID-19.

Cold viruses are also coronaviruses. When you have a cold or the flu, the virus attacks the cells lining the upper respiratory system (the passage from the mouth and nose, through the throat and voice box, and into the large windpipes). These viruses can also spread to other organs like the lungs, causing pneumonia.

As these cells become infected, the body responds with a variety of different mechanisms, called the immune response. This response is how the body fights off the infecting foreign organism. Afterward, we hopefully become immune to repeat infection as the body remembers how to defend itself.

Flu season comes about as the “old” virus mutates into a “new” virus and starts spreading around the world. This spread follows the prevailing winds, so we call it the Asian Flu in North America. Our scientists get the organism while it’s in Asia and develop a vaccine for it, which is why there’s a new vaccine every year.

The immune response generated to fight the organism causes the sick-all-over feeling we get with the cold or flu. The body fights off these critters with a systemic (body-wide) response. For instance, our fighting cells signal the body to raise its temperature, which helps kill these organisms (just like boiling water!). Sometimes, the byproducts of the fight enter our bloodstream and cause an unwanted systemic reaction, like muscle aches and pain.

We feel sick from these illnesses because our immune system doesn’t tolerate foreign invaders and fights them off vehemently. Our bodies deal with any invasion as a threat to our health. If not dealt with promptly and completely, a minor attack could become life-threatening, such as when a cold develops into pneumonia. That’s how the phrase “you’ll catch your death” came about in the pre-antibiotic age.

The common cold

We all know common cold symptoms: stuffy nasal passages, phlegm and mucous production, coughing, low-grade fever, chills and general malaise. Sinus involvement can cause pressure buildup and pain around the eyes and nose, leading to severe headache, whereas throat involvement can cause pain and swelling of these tissues, making swallowing difficult and painful. If the vocal cords are affected, you may have trouble breathing and talking.

Viral illnesses are acute and, thankfully, mostly short-lived. To date, we have not developed agents to fight these organisms. When a viral illness persists for longer than two weeks, a secondary problem is usually the cause. At this point, antibiotics can become useful in treating super infections that develop on top of viral illnesses. Nowadays, we must also consider COVID-19 as the cause of a progressive cold.

This brings up the topic of early testing. Since a cold, the flu and COVID-19 have similar symptoms, it’s now recommended that we seek out testing to determine which illness we have. This also includes being exposed to people with symptoms, even if they insist they just have a cold or allergies. You won’t really know unless you get tested!

Common cold treatment is symptomatic and supportive. Rest, keeping up with fluids and nutritional requirements, and keeping warm and dry are the cornerstones of treatment. Aspirin, acetaminophen or ibuprofen can be used for fevers and general malaise.

Antihistamines and decongestants, like Sudafed, can be used to reduce the swelling and mucous production of the respiratory and nasal passages. Cough medicine’s relief is based on mild narcotic suppression of the brain’s coughing center, and expectorants help loosen the mucous of the respiratory tract so you can bring it up and out. Robitussin-DM is one of many products available; read labels carefully to compare ingredients and to become aware of possible side effects and contraindications. Remember, antihistamines can cause significant drowsiness, an inability to concentrate and visual disturbances.

The flu

Influenza viruses are also respiratory tract infections; however, they affect the entire respiratory tract and are more often blood-borne, therefore impacting the entire body. Muscle aches, abdominal pains, diarrhea and headaches are common. Because of its severity, the flu can easily progress to pneumonia.

Treatment for the flu, like the common cold, is largely supportive. With persistent symptoms or other signs of progressive disease, antibiotics may be given, but as with colds, antibiotics should not be used routinely. In general, I do not recommend combination medicines. It’s better to know exactly what you are taking and why. This generally cuts down on side effects, is more cost-effective, and allows more specific dosing than combination remedies. Don’t forget aspirin and ibuprofen, which not only treat fever and aches but also reduce swelling and inflammation. These excellent drugs can make you feel much better.

We do have antiviral flu drugs like Tamiflu, but they are only effective if given within a day or two of acquiring the illness. Elderly and immunosuppressed patients should receive these agents.


You can only catch a cold or flu by direct exposure to the viral organism, which usually occurs when an infected person coughs on you or shakes your hand after coughing on his or her hands. The best prevention is avoiding close contact with sick individuals and large crowds (where statistically many people will be infected), which is what we’re currently doing to prevent the spread of COVID-19.

Being exposed doesn’t necessarily mean we will get ill. If the viral load (exposure dose) isn’t too great, a person in good health with good immunity may fight off the virus before getting sick. In any viral illness, some people never show symptoms even though they have the illness and can spread it, which is why we wear masks to prevent spreading or getting the disease.

The flu vaccine contains parts of the dead virus, which stimulates our bodies to mount an effective immune response. With this large and specific boost to our immune system, we should be able to fight off any routine exposure to the flu. Currently, doctors recommend giving the flu vaccine to anyone over 6 months of age, especially the immunosuppressed, the elderly, those dealing with exposed populations like teachers, those with severe pulmonary and cardiac disease, and a few other high-risk conditions.

With COVID-19, we are working on getting an effective vaccine and studying preventive medication strategies as well.

Remember that testing is the key to preventing spread and limiting mortality, not just for COVID-19 but also for the flu. Stay well.

Gino Bottino, MD, has had wide experience in medical practice and emergency medical matters. A member of United States Power Squadrons First Aid Support Team (FAST) and the Safety Committee, Gino also has a background in competitive sail racing and is familiar with health-related problems afloat.

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