COVID-19 and the flu: What’s the difference?

With Amesh Adalja MD

How to distinguish between the symptoms of viruses this cold and flu season

Fall brings the beginning of many pleasant things: leaves change color, pumpkin pie, Halloween, and apple picking. Unfortunately, it also signals the advent of cold and flu season. Now, in addition to the usual threat of flu this time of year, we also have the threat of COVID-19.

How is COVID-19 different from the common cold or flu?

From a medical point of view, it can be surprisingly difficult to tell them apart without a confirmed test. Amesh Adalja MD, principal investigator at the John Hopkins Center for Health Safety, has treated COVID-19 patients since the beginning of the epidemic and has sought to educate the general public. When asked how to distinguish between COVID-19 and influenza, he replied: “It is impossible to distinguish between them clinically.” He went on to explain: “There is no way to know if your symptoms are due to the common cold, COVID-19 or influenza. That is why it is so important to get a flu shot now.”

Is COVID-19 Really Deadlier Than The Flu?

While the initial symptoms of COVID-19 are in many ways identical to those of influenza, the risks are not.

Differences between coronavirus and influenza include:

• COVID-19 has already killed more than 219,000 people in the US, making it far more deadly than the common flu.
• For seasonal influenza, the mortality rate is usually less than 0.1%.
• For COVID-19, the death rate can reach 3-4%.
• According to the Centers for Disease Control and Prevention, COVID-19 also appears to spread more easily than the flu because it is transmitted through the air. Patients take longer to develop symptoms and may remain contagious with COVID-19 for longer than influenza.
• Among COVID-19 patients, 80% of cases are asymptomatic or mild, while another 15% are serious infections that require oxygen and hospitalization, and 5% are critical infections that require ventilation. This is a substantially higher rate of hospitalizations and serious infections than the common flu. There are already indicators that COVID-19 may have long-term effects for patients, including lung disease and cognitive decline.
• While there is an annual flu vaccine, as of yet there is no vaccine against COVID-19.
• Another key difference is the transmission speed. Influenza has a shorter incubation period between the time of infection and the onset of symptoms than COVID-19.
• Then there is the serial interval. The serial interval is the time between successive cases of a virus. For influenza, the serial interval is approximately 72 hours. For COVID-19, it is approximately 5-6 days. This is one of the reasons that COVID-19 spreads faster than the flu.

What are the Similarities Between COVID-19 and Flu

Common symptoms of coronavirus and influenza include:

• Fever
• Cold
• Cough
• Difficulty breathing
• Fatigue
• Sore throat
• Nasal congestion
• Muscle pains
• Headaches
• Stomach problems including vomiting and diarrhea.

Symptoms that are unique to COVID-19 (and not the flu) include:

• Loss of the sense of smell and taste.
• Conjunctivitis, also known as pink or inflamed eyes
• Blood clots in the veins and arteries of the lungs, heart, legs, or brain.
• Low blood oxygen levels
• Inability to breathe
• Rashes and other skin problems
• Mental fog, confusion, and other cognitive problems
• Persistent chest pain or pressure
• Feeling unable to wake up or stay awake
• Bluish face or lips

Additionally, COVID-19 can cause multisystem inflammatory syndrome in children (MIS-C). This is a syndrome in which different parts of the body can become inflamed, including the heart, lungs, brain, kidneys, skin, and gastrointestinal organs.

The CDC advises parents to contact a medical provider immediately if their child exhibits the following symptoms:

• Fever
• Abdominal pain
• Vomiting
• Diarrhea
• Neck Pain
• Eruption
• Bloodshot eyes
• Extreme fatigue

The CDC advises parents to seek immediate emergency care if their child exhibits any of the following symptoms:

• Labored breathing
• Persistent chest pain or pressure
• Confusion and / or cognitive difficulties
• Inability to wake up or stay awake
• Bluish lips or face
• Severe abdominal pain

Anyone experiencing the symptoms of COVID-19 and / or the flu should contact their primary care physician. And don’t panic! Even if you have COVID-19 instead of the common flu, 80% of cases are asymptomatic or mild.

Tips for preventing COVID-19 and influenza

While there is no vaccine or cure for COVID-19, now is the time to get your flu shot and follow health guidelines to prevent the transmission of either virus. The following guidelines are recommended by the Mayo Clinic based on the recommendations of the Centers for Disease Control (CDC) and the World Health Organization (WHO). Following the instructions to prevent the coronavirus also has the advantage of reducing the risk of contracting influenza, so it is beneficial for everyone!

• Avoid large events and mass gatherings.
• Avoid close contact with anyone who is sick or has symptoms.
• Stay home as much as possible and maintain a social distance of at least six feet between yourself and others, especially if you are at higher risk for serious illness. Be aware that some people can have COVID-19 and pass it on to others, even if they have no symptoms or don’t know they have COVID-19.
• Wash your hands frequently with soap and water for at least 20 seconds or use an alcohol-based hand sanitizer that contains at least 60% alcohol.
• Cover your face with a cloth mask in public spaces, like the grocery store, where it is difficult to avoid close contact with other people, especially if you are in an area with ongoing community spread.
• Cover your mouth and nose with your elbow or a tissue when you cough or sneeze. Discard the used tissue. Wash your hands immediately.
• Avoid touching your eyes, nose, and mouth.
• Avoid sharing dishes, glasses, towels, bedding, and other household items if you are sick.
• Clean and disinfect high-touch surfaces such as doorknobs, light switches, electronics, and counters.
• Do not go to work, school, or public areas if you are sick, unless you are to receive medical attention.
• Avoid public transportation, taxis, and carpooling if you are sick.

Last update in 10/20/2020

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