Introduction 

Each year, as the weather cools down and flu season begins, many people find themselves sniffling, coughing, and wondering if they have the flu or just a common cold. Both of these illnesses share similar symptoms as they’re contagious respiratory illnesses, but generally, the flu is worse than the common cold. The flu can also result in serious complications, including pneumonia and bronchitis, which can result in death. The common cold is often self-limiting and generally doesn’t result in serious health problems.

but they do differ and this article will divulge into the key differences between influenza and the common cold!

Causes of influenza and common cold

Influenza (also known as ‘flu’) is a contagious respiratory illness that affects the lungs and other parts of the respiratory system. There are four types of influenza viruses, influenza A, B, C, and D. Influenza A and B viruses cause seasonal flu epidemics, influenza C infections generally cause mild illness and are thought not to cause epidemics and influenza D viruses primarily affect cattle, not humans.¹

Common cold: The common cold is a contagious upper respiratory infection that affects the nose, throat sinuses and windpipe (trachea). While many viruses can cause the common cold, the most prevalent common cold virus is the rhinovirus. However, other viruses such as coronaviruses, respiratory syncytial virus (RSV), and parainfluenza can also cause cold symptoms.² Statistically, adults catch two to three colds a year, while young children catch a cold four or more times a year.

Transmission methods

Influenza: The flu is highly contagious and influenza is spread by inhalation of infectious respiratory droplets produced by an infected person when they cough, sneeze, or talk. Influenza can also spread through touching surfaces where infected droplets have landed and then proceeding to touch the mouth, nose, or eyes. 

Common cold: The common cold is also very easily spread to others, and it spreads through direct contact with infected individuals, such as by shaking hands, or by touching surfaces that have been contaminated with cold viruses and then touching the face.

Common symptoms

Influenza: Flu symptoms are generally more severe than those of a common cold. Common flu symptoms include:

• A sudden high temperature of 38 C or above
• Body aches
• Feeling exhausted
• A dry cough
• A sore throat
• A headache
• Difficulty sleeping
• Loss of appetite
• Diarrhea or stomach pain
• Feeling nauseous and being sick

Common cold: Cold symptoms are generally milder than those of flu and include:

• Runny or blocked nose
• Mild fever 
• Sneezing
• Coughing
• Sore throat
• Mild headache
• Mild body aches

Duration

Influenza: This generally lasts longer than the common cold. Typically lasting from 1-2 weeks. However, most symptoms go away in 4-7 days, but the cough and tired feeling may last for weeks and appetite may still be lower.

Common Cold: The common cold typically lasts from 7-10 days. Generally speaking, the first few days are typically the worst, with symptoms gradually improving after. If the cold symptoms do not seem to be improving after a week, you may have a bacterial infection, which means you need antibiotics.

Further complications

Influenza: As stated above, influenza can result in severe complications such as pneumonia, bronchitis, and worsening of chronic medical conditions.³ For example, people with asthma may experience asthma attacks while they have the flu, and people with chronic heart disease may experience a worsening of this condition triggered by the flu.

Common cold: Usually common colds clear up without causing any further problems. However, they can lead to secondary infections such as sinusitis (ear infections), and people with asthma or COPD may experience their symptoms worsening.

Treatment

Influenza: This is known as a self-limiting condition, thus your body’s immune system should be able to fight them off on its own within a few days. Although, people experiencing mild symptoms should stay home to avoid infecting others, rest, get plenty of sleep, drink plenty of fluids, and take paracetamol or ibuprofen to alleviate the symptoms of a temperature and treat aches and pains. However, people who are at high risk or with severe symptoms should be treated with antiviral medications such as oseltamivir or zanamivir. High-risk individuals are pregnant, children under 59 months of age, aged 65 years and older, living with other chronic illnesses, receiving chemotherapy, and having a weakened immune system possibly due to HIV or other conditions.

Common cold: Again, this is another self-limiting condition. However, if you have a common cold, it is recommended to rest, drink plenty of fluids, eat healthy food, gargle salt water to soothe a sore throat (not suitable for children), breathe in steam to ease a blocked nose, and take medicines like paracetamol or ibuprofen to alleviate the symptoms.

Prevention

Vaccination

Influenza: The most effective way to prevent influenza (flu) is through vaccination. The flu vaccine is updated each year to match circulating strains and is recommended for people at higher risk of getting seriously ill from the flu. Vaccination can reduce the severity of illness and prevent further complications.

Common cold: Sadly, there are currently no vaccines for the common cold. This is due to a high number of viruses, more than 200 kinds, that can cause the common cold. Prevention relies on good hygiene practices and immune symptoms.

Hygiene practices

Good hygiene practices for Influenza and the common cold include:

• Washing hands frequently with soap and water for at least 20 seconds to slough germs off the skin.
• Alcohol-based hand sanitisers should be used when soap and water are not available.
• Avoiding close contact with sick individuals
• Avoiding touching the face, especially the eyes, nose, and mouth
• Covering coughs and sneezes with a tissue or elbow
• Disinfecting frequently touched surfaces

Conclusion

While both influenza and the common cold are respiratory illnesses with overlapping symptoms, the causative organisms for both conditions are from different viruses. Generally, influenza tends to be more severe, with a sudden onset of high fever, intense body aches, and significant fatigue. This can potentially lead to further complications which are more serious than just the common cold. Additionally, the common cold occurs with a milder fever and generally milder symptoms like a runny nose, and sore throat, and has a gradual onset. 

Prevention through vaccination (for influenza) and good hygiene practices (for both illnesses) is crucial. Also understanding when to seek medical attention is critical to prevent further complications, especially for influenza. Therefore, stay informed, practice good hygiene, and make sure you get your flu shot annually to stay safe and healthy during the cold and flu season.

FAQs

Can a common cold turn into the flu?

No, it can’t. The flu and the common cold are caused by different viruses which means that if you have a cold, it cannot develop into the flu. Unless you contract the influenza virus whilst having a common cold.

Can you have a common cold and the flu at the same time?

Yes, this can happen. However, this is rare and, likely, you will not even notice a common cold if you already have the flu.

How are the flu and the common cold treated?

Influenza can be treated, especially in high-risk individuals, with antiviral medications such as oseltamivir or zanamivir, but this does need to be prescribed by a doctor. For the common cold, there is no specific antiviral treatment.

Can you die from the flu and the common cold?

Influenza can lead to further complications like pneumonia which can lead to death. However, to an extremely low extent, it’s possible to die from the common cold.