The Cold vs The Flu: Reading the Clues

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by Vanessa Monteiro

The uncomfortable symptoms of a common cold may hit you suddenly or sniffles, coughing, and tiredness may slowly creep in. You know you’re not feeling well, but how do you know the difference between cold and flu?

Last year, the Center for Disease Control and Prevention (CDC) recorded the longest running peak flu season at 19 weeks (1) in the USA since 2009. With illness being so prevalent, understanding the difference between the common cold and the flu is important, so you’re able to use the best remedies and treatments for a speedy recovery.

The Common Cold

This illness is caused by a virus that exists specifically in the nose (though it can affect the sinuses, ears, and airways). With the common cold, you will mostly experience a stuffy nose, sneezing, and a sore throat for about a week, but it can last up to 2 weeks (2).

Rhinoviruses are responsible for the majority of colds, but there are over 200 different types of cold viruses (3). These viruses can only multiply within the cells of your nose but they can be passed on from an outside surface to a new host. When the virus infects a cell in our body it begins to reproduce rapidly until it causes the infected cell to die and break apart. This releases all the new virus particles, which in turn infect new cells in your body (4).

The incubation period, the time from infection to experiencing your first symptoms, is about 24 – 72 hours, as the body recognizes and begins to fight the infection (5). These symptoms occur when your immune system, the defense team in your body, sends out white blood cells that release inflammatory mediators. The mediators prompt an increase in mucus secretion and induce sneezing reflexes as a method to remove the virus (6).

man with a scarf drinking a warm beverage from white mug sitting on bed

For both the cold and the flu, you need to rely on your immune system to do its job and let the illness run its course.


The flu—medically named influenza— is a respiratory infection by a virus that causes distress to your nose, throat, and lungs (7). The onset of the flu is typically quite quick and is commonly associated with a high fever (over 100.4°F or 38°C), achiness and fatigue (or weakness). Though you most often recover from the flu on your own, this infection has the potential to advance to a stage where medical intervention is required to prevent severe complications.

The virus that causes the flu travels with moisture, typically droplets that are created when someone who is sick sneezes. The droplets can transfer via direct contact, but often times are picked up when you interact with an object— such as a telephone—that has been in contact with a sick person. What makes prevention of this illness difficult is that people are often contagious before they show symptoms of sickness, so practices like hand-washing are very important to reduce the transfer of germs.

One unique feature of the influenza virus is that it adapts to your body over the years. When you get the flu and recover, your body learns from being sick, creating antibodies (immune system proteins) (8) that can target that particular strain of virus as an intruder. However, if you encounter a new strain that your body is not familiar with, it will need to learn how to recognize and eliminate the virus from scratch.

Flu vs. cold: the common symptoms

For both the cold and the flu, you need to rely on your immune system to do its job and let the illness run its course. Below is a list of the common symptoms you’ll see with each illness, so you have a better idea of whether you have a common cold or the flu. By knowing what you are sick with, you can do a better job treating those symptoms and hopefully reduce your misery as you recover.

Understanding Differences in Signs & Symptoms (9)

Debunking myths about cold & flu

With most medical advice suggesting rest and home remedies for both cold and flu illnesses, it is easy to follow the advice of others when you are feeling under the weather. However, not all sayings hold truth, and it is vital to know when traditional advice may not be in your best interest.

Myth: feed a cold, starve a fever

This saying can be traced back to A shorte dictionarie for yonge begynners (10), a book from the 1700s written by John Withals. John believed fasting would be beneficial during a fever as you often generate heat after eating, which could add to the temperature of a fever.

However, the high temperature you experience with a fever actually benefits you as it’s the body’s way of eliminating intruders who cannot survive the heat. For a fever to exist, your body turns up your metabolism, which requires a lot of energy. If you then stop eating, your body will be working in overdrive but with nothing to fuel the system. Therefore, the best advice to follow is to feed a cold, as well as a fever!

Myth: you need antibiotics to cure the cold or flu

As you now know, both the cold and flu are viral infections. Since antibiotics are used specifically for killing bacteria, they have no effect on illnesses caused by a virus (11).

In fact, taking antibiotics unnecessarily can cause greater problems for you in the future. Each time antibiotics are used, targeted bacteria are killed off but, there is always a risk that a few survive. These few cells continue to grow, multiply and adapt to your body to improve their resistance to antibiotics. Over time this can result in a superbug (12), an antibiotic-resistant bacterial strain that is very difficult to treat and can even become incurable.

Myth: the flu vaccine can give you the flu

Typically, the flu vaccine is given through an injection. This injection contains an inactivated version of the flu virus which cannot infect your body, or it contains a component of the virus to help your body learn and recognize the real flu more easily (13). The World Health Organisation (WHO) recommends that you get the flu shot every year, as the contents of the vaccine are updated annually based on the strains most likely to appear in the upcoming season (14). Though you cannot contract the flu from the vaccine, there can be side effects such as soreness, headache or fever, but these typically subside within a day or two.

You now know that both the common cold and the flu are very common illnesses you will see seasonally. For either case, you want to treat the symptoms to feel better and give your immune system its best chance by keeping hydrated, eating well, and resting.

Sickness typically lasts a few unfortunate days (typically up to 10) (15), but there can be cases where the flu develops into something more serious. In such cases, it becomes important to seek medical assistance. If you really want to win this cold and flu season, prevention is your best friend!