OSF: COVID-19 More Contagious & Deadly Than Flu

Nationwide, the number of new daily COVID-19 infections continues to rise, spanning every region of the country. It has even reached the highest levels of government with the announcement that the president and first lady have contracted the virus.

With that reality, health leaders say it’s important to understand the important differences between the flu and COVID-19 that share some common symptoms but impact the body differently.

Some people ignore precautions, such as wearing masks and maintaining a minimum six feet distance, arguing those measures have never been required with the seasonal flu which results in more than 10 million cases each year in the United States.

Dr. Cliff Martin, chief medical officer of three OSF HealthCare hospitals in western Illinois, says infection with both viruses begins with some similar tell-tale signs such as fever, cough, head and body aches, but COVID-19 symptoms can intensify rapidly within a week or so. Those who get seriously ill with COVID can require a much longer time in intensive care than most people with the flu.

“Each year when we see that (flu), we see that normal progression of what we call ICU progression – two or three days in ICU and they start to improve; maybe go to a less intensive care bed for a little while and then home where with folks with COVID-19, sometimes we see weeks on end of needing ICU care and then ultimately sometimes, lives are lost.”

According to Dr. Martin, the novel coronavirus creates a much more intense inflammatory response in the body than the flu. In part, doctors and researchers believe the immune system goes into overdrive, harming many of the cells that were not infected.

“The virus overwhelms the system, causing blood clotting, causing effects on the cytokine system which then causes more of a flurry of inflammation in the small tissues in the blood vessels and scarring and having those long-lasting changes.”

Some patients may report lingering symptoms ranging from mild issues, such as continued loss of taste or smell, to more serious ones, such as heart palpitations, chest pain, shortness of breath, extreme fatigue, cognitive difficulties or recurring fevers. Different strains of influenza can also leave patients with serious health issues, but the breadth and extent of COVID’s impact is what makes it so different.

Both COVID-19 and flu spread through respiratory droplets or aerosols released through talking, sneezing or coughing or if a person touches a surface with one of the viruses and then touches their mouth, nose or eyes. But Dr. Martin says the novel coronavirus spreads more quickly because there is no vaccine and therefore little immunity within the population.

“It just spreads faster because it can. We have seen that one or two individuals in a community turns into 10 or 15 and that 10 or 15 turns into 1,000 and so on and so on. So, it’s a highly contagious virus.”

The Centers for Disease Control and Prevention (CDC) Director Robert Redfield has told federal legislators that to date, preliminary data shows more than 90% of Americans remain susceptible to COVID-19 — meaning they have not yet been exposed to the coronavirus.

With no vaccine or antiviral medications like those that are available for the seasonal flu, COVID-19 poses a bigger threat because even though about 80% suffer little to no symptoms, the numbers show the virus is about 10 times more deadly.

Dr. Martin says that’s borne out by the data. He points out that for the 2018-2019 flu season in the United States there were about 28,000 flu-related deaths. COVID-19 has claimed 200,000 lives in the U.S. during the same six months.

“So to me, that means it's a much more deadly virus. Is it because it’s new and it does overwhelm the body differently? Probably so, but that’s the reality. Right now we are dealing with a very deadly infection.”

Even though many people are suffering from varying degrees of “COVID fatigue” from having to adhere to social restrictions, Dr. Martin warns those precautions are the only defense against the novel virus until at least 80% of the population can receive whatever vaccine is developed. Even then, he says there could be lingering concerns about how effective it is and how long the immunity it provides will last.

The good news is that it appears the precautions could save more lives and lessen the impact of this year’s flu season. Dr. Martin highlights countries in the Southern Hemisphere are reporting lower numbers of flu cases this year compared with previous years—and health officials are attributing the decline to widespread coronavirus restrictions such as mask wearing, travel restrictions, and social distancing.

You can get an annual influenza vaccine to help reduce the risk, severity and the chance of suffering serious complications from the flu.

More like this:

IDPH Advises Precautions As Warm Weather Carries Increased West Nile, Rabies Risks

May 16, 2026

IDPH Urges Flu Shots, Other Preventive Measures as Influenza Rates Climb Statewide

Jan 5, 2026

Local Doctor Shares How to Care for Winter Illnesses and When to Seek Medical Attention

Jan 23, 2026

100 Years Ago: Flu Epidemic Hits Alton Catholic Orphanage

Mar 22, 2026

FSIS Issues Public Health Alert for Headcheese Deli Meat Products That May Be Contaminated With Listeriapha

May 14, 2026