Common cold vs flu – can you tell the difference?

It’s that time of the year again. Summer holidays are over and children are heading back to school, while their parents are going back to work. Also, it is the time of the year we so often associate with annoying, long-lasting colds. Respiratory infections are some of the most common presenting symptoms in family doctors’ offices. They also cause a lot of confusion that often leads to overuse of antibiotics. In this article, I will try to shed some light on one of the topics I am commonly asked about by both patients and friends.

The common cold and the flu are easily (and unsurprisingly) confused. Although they do share many similarities, there are some very important differences that I believe everyone should be aware of. Both are caused by viruses. However, one of them is a relatively benign disease that affects most people regularly, while the other is a serious, in some cases, life-threatening disease that needs to be taken seriously.  

Common Cold

So let’s begin with the common cold. As the name implies, it’s common. Most of us have had numerous episodes of common cold throughout our lifetimes. It is caused by any of a number of different respiratory viruses and is contracted once the inner lining of the nose gets exposed to the virus. It is not caused by cold weather itself. Depending on the exact virus causing it, symptoms vary, with one common feature – they are relatively mild. Our eyes can get red and itchy, our throat can get dry, our nose can feel clogged. Fever is uncommon, and if present, it is rarely high. It goes away on its own within a few days regardless of whether we do anything about it or not. Ironically, the common cold is one of the diseases that modern medicine has discovered no cure for as of yet.

Common Cold Prevention

Unfortunately, it may not always be possible to prevent the common cold. Especially in the winter months, when we all tend to spend a lot of time inside, in close proximity to the other people, the chance of the disease spreading is high. Hand washing and proper hygiene may be our best bet. Alternatively, a face mask. But that may just be too much. There is no evidence to suggest high doses of vitamins or other supplements are a successful preventive measure. On the plus side, the disease is benign and does not warrant any more space in this article.


That brings us to our second topic and another respiratory infection, the flu. Unlike the common cold that may be caused by multiple different groups of viruses, the flu is caused by a specific virus called “Influenza”. It occurs almost exclusively during the so-called “flu season” in late fall and winter and presents much more abruptly and severely than the cold. The most common initial symptoms are fever (often above 102 F or 39 C), malaise and muscle aches. Typical cold symptoms usually don’t occur until later.

How Serious Is It?

The flu is highly contagious, meaning it would be ideal to stay at home for about one week following the onset of symptoms. Moreover, flu complications aren’t uncommon and can be serious. According to the CDC website, in the United States, there are on average more than 200,000 flu-related hospitalizations and as much as 27,000 deaths per year. People with chronic medical conditions, young children and the elderly are at a particularly high risk of complications. Therefore, once the flu is suspected, the affected individual should stay at home for a few days to protect both self and others. Also, unlike the common cold, flu responds to certain medications so a visit to the doctor’s office, especially early in the course of the disease is beneficial.

Can We Prevent It?

The answer to this question is a resounding yes. Our ability to prevent the flu far exceeds our ability to prevent common colds. The fact that flu is always caused by one of the strains of the Influenza virus means that it was possible to develop a highly efficacious vaccine. Obviously, no intervention is perfect, and neither is the vaccination. The virus can change, sometimes considerably and unpredictably. The consequence of such changes can occasionally be a decreased efficacy of the vaccine against that particular strain. However, all the available evidence suggests that overall, flu vaccination is extremely safe and is the best way to prevent the flu and one of the best ways to decrease our chance of serious health problems over the upcoming few months. I am aware of the public concerns surrounding vaccinations so a separate blog post dedicated to the topic is likely to be written in the future.

Antibiotic Use

Finally, a word about the overuse of antibiotics. They have no role in the treatment of either of the conditions I have written about in this article. Both the common cold and the flu are caused by viruses. Antibiotics, on the other hand, are effective only against bacterial infections. Not only are they useless in the treatment of the flu, but they can also be harmful. Medications for the flu do exist but they are a different class of drugs. Antibiotic overuse is another one of the topics that are too vast to be summed up in a single paragraph and will be addressed more thoroughly in subsequent articles.

To Sum Up…

…when you develop symptoms typical of a cold (unless they are severe or you suspect there might be complications), a medical consult may not even be necessary and the best advice anyone can provide is – patience. On the other hand, when you develop symptoms of the flu, a visit to your doctor’s office is something you should seriously consider.  


Disclaimer: Reading this blog is not a substitute for regular medical check-ups. While every effort is made to ensure the quality of the information provided, it is not tailored to the needs of each individual patient and should therefore not be perceived as equivalent to a medical consultation. If you have any health-related questions, please talk to your doctor.


As a medical doctor very passionate about science, I strongly believe that educating the public about health is one of the most important aspects of improving healthcare outcomes. Also, as a sports fan, I am very keen on promoting active lifestyle.