Is It Influenza Or Covid-19 Coronavirus? How To Tell The Difference

The influenza virus is not the Covid-19 coronavirus. The Covid-19 coronavirus is not the influenza virus. Both are respiratory viruses. Both can infect cells in your respiratory tract. But they’re not the same.

The two are completely different viruses. Since viruses are very small and don’t wear little name tags, how then do you tell whether you’ve been infected by one or the other or even both?

A key point to remember is that the Covid-19 coronavirus, otherwise known as the severe acute respiratory syndrome (SARS-CoV2), is a novel virus. In this case, novel doesn’t mean that it appeared in the novel 50 Shades of Grey. Instead, novel means new to humans. That’s what happens when a virus that normally infects another type of animal attains the ability to infect humans for the first time. This means that your immune system probably has never seen the SARS-CoV2 before this pandemic. As a result, your immune system ends up behaving like an inexperienced guy on a date for the first time. Except, this date is with a sphere covered in spikes. It looks a bit like a spiky massage ball, except that this spiky ball gives terrible massages:

Imagine, as a result, your immune system getting very confused, saying something like, “hey you didn’t mention spikes on your dating profile,” and not knowing quite how to react. When your immune system realizes that the date with the virus has turned out to be something bad, really bad, it can start firing in random directions.

By contrast, the flu virus is more akin to that classic bully, like Biff Tannen, Joffrey Baratheon, Bellatrix Lestrange, or a racoon carrying nunchucks. There’s a good chance that your immune system has seen bullies like this before. Getting the seasonal flu vaccine can provide a preview of this kind of bully. If your immune system has seen a given influenza virus already, it will have a better sense about how to react. Your immune system may simply say “be best” and respond rapidly and effectively.

So not only are the Covid-19 coronavirus and the influenza virus two completely different viruses, your immune system’s experiences with them to date are likely very different. Therefore, the damage caused directly by each virus and by your immune system’s reaction to each can be very, very different.

That being said, it can frequently be difficult to determine whether you have the flu or Covid-19 without actual testing. Nonetheless, here are several possible differences between the infections with a big caveat at the end:

1. Covid-19 symptoms tend to take longer to emerge after you’ve been infected.

Covid-19 symptoms can develop two to 14 days after you are first infected. On average it takes about five days. That’s about half a Scaramucci, one fifth of a Flynn, or one fortieth of a Bannon or a Gorka. Meanwhile, flu symptoms tend to develop one to four days after infection or one tenth to four tenths of a Scaramucci, somewhat sooner

2. Covid-19 symptoms tend to emerge more gradually.

The flu can hit you like a ton of bricks. Picture yourself feeling fine, going about your daily business watching latkes heat up in your microwave while singing Taylor Swift’s “You Belong With Me” to them, when suddenly you begin feeling lousy. It’s a sudden onset of symptoms like a fever, chills, muscles aches, headache and fatigue. Instead, of a latke to deal with, you quickly have a lot of symptoms to deal with within a few hours.

By contrast, the onset of symptoms for Covid-19 can be quite different. Instead of a ton of bricks, it can feel like bricks of varying sizes, shapes, and consistencies being tossed at you in various directions or stuffed down your pants. You may notice a loss of taste and smell first. Or a fever. Or a cough. Symptoms can appear gradually and can be mild at the beginning. But after the first week, like the movies Dark Phoenix and Lucy, things can go from a not-so-great beginning to much worse.

3. The course of Covid-19 is more unpredictable.

With the flu, symptoms tend to follow a more typical trajectory. You feel most like doo-doo early on, soon after symptoms appear. If things are going to go downhill, they usually do so during the first several days of symptoms. Otherwise, your symptoms will likely improve with time. Of course, there are exceptions. For example, things may be different if you subsequently get infected by something else like bacteria causing pneumonia in your lungs or a racoon hitting you with nunchucks.

On the other hand, the course of Covid-19 can be much more all over the place. It can be somewhat like a groundhog piloting an airplane in a storm while drinking tequila: highly unpredictable with significant ups and downs. You may feel reasonably OK during the first week and then spiral downhill the second week. Or your symptoms can change on a day-to-day or even seemingly on an hour-to-hour basis. It is much more difficult to predict what may happen. It can be unsettling trying to determine whether your new onset shortness of breath is a reaction to a video of BTS singing “Dynamite” or a sign that you may need to go to the hospital soon.

4. Covid-19 can cause a loss of taste or smell.

Losing your sense of taste is not typical for the flu. In this case, losing a sense of taste doesn’t mean wearing velour tracksuits or plating all of your walls and furniture with faux gold. It means not being able to sense different flavors in your mouth. So when you have avocado toast in your mouth and you don’t get all the feels, consider Covid-19 as a possibility.

Loss of smell is another possible Covid-19 symptom. As a Late Show with Stephen Colbert segment showed, such a symptom left actor Hugh Grant wanting to smell people’s armpits:

This is not typical when you have the flu, assuming that smelling other people’s armpits is not usually your thing. So if your roommate’s B.O. suddenly goes B-no, be on the lookout for other signs of Covid-19.

5. Covid-19 can have a wider range of unusual symptoms.

As the Centers for Disease Control and Prevention (CDC) indicates, both Covid-19 and the flu can result in fever, chills, cough, shortness of breath, difficulty breathing, fatigue, sore throats, runny or stuffy noses, muscle pain, body aches, headache, vomiting, or diarrhea.

However, eye problems, skin rashes, and an erection lasting longer than four hours are just some of the usual symptoms that have been reported for Covid-19. Physicians are still trying to figure out all of the possible problems that Covid-19 can cause. Certainly, if you have an erection lasting longer than four hours, don’t just say, “oh, darn it’s the flu again.” Similarly, any unusual or unexpected symptoms in combination with more common symptoms such as fever, cough, and diarrhea should make you consider Covid-19 as a possibility. The words erection and diarrhea don’t typically go together.

6. Covid-19 is more likely to cause serious problems, including long-term problems.

Covid-19 has a significantly higher risk of death than the flu and seems more likely to leave you with persistent symptoms. According to the World Health Organization (WHO), “80% of infections are mild or asymptomatic, 15% are severe infection, requiring oxygen and 5% are critical infections, requiring ventilation. These fractions of severe and critical infection would be higher than what is observed for influenza infection.” It’s not typical to see 20 out of every 100 or two out of every 10 people with the flu requiring oxygen or ventilation.

The WHO also indicates that “mortality for COVID-19 appears higher than for influenza, especially seasonal influenza. While the true mortality of COVID-19 will take some time to fully understand, the data we have so far indicate that the crude mortality ratio (the number of reported deaths divided by the reported cases) is between 3-4%, the infection mortality rate (the number of reported deaths divided by the number of infections) will be lower. For seasonal influenza, mortality is usually well below 0.1%.”

There are also more and more reports of people suffering from long Covid-19, symptoms that persist well beyond the initial infection for weeks, even months. For example, in the following 60 Minutes Australia segment, actress Alyssa Milano described her struggles with “long hauler” Covid-19:

It’s not clear what percentage of Covid-19 progress to long Covid-19, but the longer your symptoms continue, the more likely you have Covid-19 than the flu.

7. Covid-19 is more contagious than the flu.

While a single person (meaning one person and not someone who is unattached) with the flu on average can transmit the virus to one to two other people, a single person infected with the Covid-19 coronavirus on average can on average transmit the virus to two to four other people. The Covid-19 coronavirus also seems to float in the air further and for longer periods of time than the flu virus. So the more people around you who are getting sick, the more you should consider the possibility of a Covid-19 coronavirus outbreak.

Here’s the big caveat. Don’t try to self-diagnose and try to determine whether you have Covid-19 or the flu by yourself. Covid-19 is not like having a marmot dressed in a trench coat on your head. You usually can tell pretty clearly when you have a marmot in a trench coat on your head. One way is by looking in the mirror while brushing your hair. The other is when people on a Zoom conference tell you, “we can’t hear you. You are muted. You have to unmute. Oh, you are unmuted? Well, then maybe that marmot in a trench coat on your head is covering your mouth because we still can’t hear you.”

As you can see, diagnosis of Covid-19 is more complex. Many of the distinctions between Covid-19 and influenza aren’t super clear-cut. In fact, they can be quite fuzzy. Often, it may be difficult to tell Covid-19 from the flu, especially when symptoms are mild.

That’s why Covid-19 testing is so important. Testing may be the only way to really tell whether you have Covid-19 versus something else. During the pandemic, follow these two rules: don’t go breaking my heart and don’t go self-diagnosing yourself. If you are concerned that you may have either Covid-19 or the flu, contact a trusted healthcare professional. It is important to distinguish the two because their clinical courses can end up being quite different.

Of course, viral infections aren’t like Zoom backgrounds. Just because you have one of the two viruses in your body doesn’t mean that you can’t get the other at the same time. As I’ve described before for Forbes, studies have shown that simultaneous infections with the Covid-19 coronavirus and the influenza virus are possible. So there is the chance that your answer to the question “is it influenza or Covid-19” may indeed be “yes.”

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