The 5 Differences Between Colds and the Flu

We'll show you 5 criteria that you can use to learn the differences between colds and flu. Contrary to popular belief, these are different infections.
The 5 Differences Between Colds and the Flu

Last update: 08 September, 2021

For most people, there’s no difference between colds and the flu. In fact, it’s very common for both terms to be used interchangeably in informal contexts. Although both are viral infections that share several elements in common, they actually manifest differently. Today we’ll explore 5 criteria that you can use to distinguish them.

It’s very important to know the differences between colds and the flu, as the latter is associated with a greater number of complications. Children and older adults are especially vulnerable, so allowances should be made during the seasonal season. We’ll talk about all this in this article.

Differences between colds and the flu

Since some outbreaks are practically indistinguishable from others, it isn’t always easy to differentiate between one viral infection and another. The only 100% effective way to do this is through a flu antigen test. Apart from this, you can use the following criteria to figure out the differences between colds and the flu.

1. Symptoms

Differences between cold and flu include symptoms
Cold and flu symptoms can be similar, but not the same. The difference lies in their intensity and evolution.

Symptoms are the main signs of an infection or a disease. It’s true that both share many of these, but we also find differentiating elements. Let’s see in detail which are the most frequent manifestations for each of them.

Flu symptoms

Symptoms of the flu are much more severe than those of the common cold. Contrary to popular belief, runny nose and sneezing are rare in most episodes. Among the most common signs we can highlight:

  • Throat pain
  • Fever
  • Coughing
  • Headaches
  • Fatigue
  • Muscle and joint pain
  • Shivering
  • Nausea and vomiting (only in children and older adults)

Another characteristic of the symptoms is that they usually appear suddenly. You can feel good and after a couple of hours, they appear unexpectedly. Its intensity makes it difficult for you to carry out your normal tasks.

Symptoms of the common cold

In this case, the symptoms are low or moderate intensity. Only a few times do they appear with a higher intensity, at least if we contrast the episodes with the previous ones. Fever and headaches are rare during a common cold. Instead, you may experience the following:

  • Nasal congestion
  • Sneezing
  • Throat pain
  • Coughing
  • Fatigue (mild)
  • Red and watery eyes
  • Pain in the body (general and almost always mild)

Nausea or vomiting may occasionally be experienced, although these are considered rare and only affect adults. The manifestation of flu and common cold symptoms largely depends on your health and how strong your immune system is.

2. Duration

Another difference between colds and the flu is found in their duration. Although the symptoms can last the same, around 7-14 days, the development of the symptoms is different. If you suffer from the common cold, the symptoms will appear progressively. They’ll start with a light intensity on the first or second day and will have their peak afterwards.

The same happens when getting better. After you spend a day or two with the worst symptoms, they fade until you finally feel better. It isn’t the same with the flu. In these cases, the first three days will be the worst, after which you’ll experience a slow improvement until you recover.

Although it’s possible that in a week you’ll no longer have any symptoms, some may still remain and they’ll prevent you from recovering your full health. These generally consist of mild fatigue, malaise, or headache.

3. Causes

We’ve already mentioned that viral infections are the causes of colds and the flu. However, the episodes aren’t caused by the agents themselves. The virus that causes the flu is influenza. In fact, in some contexts the disease is known as such.

There are four types of influenza viruses, although influenza A and influenza B account for the majority of infections worldwide. Influence C can also infect humans, although to a lesser extent than the above. Influenza D, the last of these viruses, affects only animals (as far as we know).

Influenza A is what causes most of the infections, and is the one that gives rise to epidemics. The H1N1 and H3N2 strains are the most common. The first caused the flu pandemic of 1918 and 2009. By contrast, common colds, according to Johns Hopkins Medicine, are caused by the infection of up to 200 different viruses.

Despite this, the rhinovirus family is usually the main cause of infections of this type. Contrary to popular belief, colds and flu are not caused by a drop in temperature. It’s viruses, albeit from different families, that trigger the symptoms.

4. Frequency of contagion

Differences between cold and flu include transmissibility
Classrooms (and other settings where many people are close together) are perfect places for the transmission of viral diseases.

According to the World Health Organization (WHO), between 5% and 15% of the population catches the flu every year. Although these infections can happen at any time of the year, most of them happen during the season that runs from October to May (known as the flu season).

The reason that so many infections originate during these dates is that in most of the world it’s an active academic period for schools, colleges, and universities. In addition to this, the winter or rainy season means that people spend much of their time in their houses (which facilitates the transmission of the virus).

Common colds occur more frequently in the population. In fact, following the American Lung Association, the average adult suffers from two to four episodes of the common cold a year. Young children are more likely to suffer from them, so they experience between six and eight colds every year.

Based on these statistics, we can say that c olds are much more common than the flu. You can go one, two or more years without getting the flu, but it’s very unlikely that you’ll go for more than 12 months without experiencing any symptoms of the common cold.

5. Possible complications

We have emphasized that the flu causes more intense symptoms, and so does this mean that infections of this type cause greater complications? The answer is yes, it does. Although it’s true that most cases don’t cause too many long-term problems, many end up in hospital, and even die.

The Centers for Disease Control and Prevention (CDC) warn that the most common complications of the flu are sinus and ear infections, pneumonia, myocarditis, encephalitis, respiratory failure, and many other conditions. On the contrary, the risk of complications is very low when it comes to a common cold.

It’s important to note that antibiotics don’t have any effect when treating the flu or the common cold. Typically patients can opt for over-the-counter medications to alleviate specific symptoms, although this won’t make the improvement progress any faster.

To feel better, what you need to do is rest and drink plenty of fluids. Also, take measures to avoid infecting people close to you. Finally, remember to get vaccinated before the flu season, wash your hands frequently, and avoid contact with mucous membranes.

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  • Eccles, R. (2005). Comprender los síntomas del resfriado común y la influenza. Enfermedades infecciosas de The Lancet. 2005; 5 (11): 718-725.

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