COVID-19 vs the Common Cold: How to Tell the Difference

A scratchy throat and a runny nose could mean either a common cold or COVID-19 and for good reason: the two illnesses share a lot of overlapping symptoms. There are some useful patterns that can point one way or the other, though testing remains the only genuinely reliable way to know for certain.

Symptoms more typical of COVID-19

Fever is one of the more useful distinguishing clues; it's a common COVID-19 symptom but relatively rare with an ordinary cold. A new loss or change to your sense of smell or taste is particularly associated with COVID-19 rather than a cold, even though it doesn't occur in every case. COVID-19 symptoms more broadly can include a new continuous cough, fatigue, muscle or body aches, headaches, shortness of breath and sometimes nausea, vomiting or diarrhoea alongside the more typical respiratory symptoms.

Symptoms more typical of a common cold

A cold tends to bring milder, more localised symptoms: a runny or blocked nose, sneezing, a mild sore throat, a cough and only slight body aches or headache, generally without a fever. Colds tend to stay fairly contained to the nose and throat, whereas COVID-19 has historically been more likely to involve the wider body, fatigue and, in some cases, the gut.

Timing can offer a clue too

Common cold symptoms usually appear quickly, within 1 to 3 days of exposure to a cold-causing virus and tend to peak early, often within the first few days. COVID-19 symptoms typically take longer to appear, generally 2 to 14 days after exposure and the overall course of illness can be more variable and, for some people, longer-lasting than a typical cold.

How long each illness usually lasts

A common cold usually clears up within 5 to 10 days. COVID-19 can resolve in a similar timeframe for many people, but symptoms have been documented lasting considerably longer in a meaningful minority of cases, sometimes for several weeks, which is part of what distinguishes long COVID from a simple prolonged cold.

Why symptoms alone aren't a reliable diagnosis

For people with mild to moderate symptoms, there genuinely isn't a reliable way to distinguish a cold from COVID-19 based on symptoms alone, since individual experiences of both illnesses vary so much. Some people with COVID-19 have nothing more than a mild sniffle, while some bad colds can bring a surprising amount of fatigue and body aches. This overlap is exactly why testing, rather than symptom-spotting, is the recommended way to know for sure.

When testing matters most

Testing becomes particularly important if you're in a high-risk group who might be eligible for antiviral treatment, if you're planning to be in close contact with someone vulnerable, or if your symptoms are more severe than you'd expect from an ordinary cold. A rapid lateral flow test at home is quick and gives a reasonably reliable answer within about 30 minutes for most people with symptoms.

What about flu and RSV?

Flu and respiratory syncytial virus (RSV) add further overlap to an already crowded picture, since both can also cause fever, cough and body aches similar to COVID-19, while typically sparing the specific loss of smell or taste more associated with COVID-19. Multiplex tests that check for several of these viruses from a single sample have become more widely available and can be particularly useful during winter, when several of these viruses tend to circulate at the same time.

Flu in particular tends to come on more abruptly than a cold, often within hours rather than gradually building over a day or two and tends to cause more pronounced fatigue and body aches than a typical cold. RSV is generally milder in healthy adults but can be more significant in young children and older people, which is part of why distinguishing between these different viruses matters more for some groups than others.

Why this overlap exists in the first place

Colds, flu, RSV and COVID-19 are all caused by different viruses, but they share the same basic target: the cells lining your respiratory tract, from your nose down through your throat and into your lungs. Because the body's inflammatory response to a respiratory virus infection looks broadly similar regardless of which specific virus is responsible, symptoms like a runny nose, cough, sore throat and fatigue show up across all of them to varying degrees. What differs more between viruses is the typical severity, the specific additional symptoms like loss of smell and how the illness tends to progress over its course, rather than there being a single symptom unique to just one of them.

Should you treat them differently while waiting to find out?

Broadly, no. Rest, fluids and over-the-counter pain relief for fever or aches are sensible for both a cold and COVID-19 while you wait for a test result or symptoms to resolve. The main practical difference is around precaution: given COVID-19's specific risk to vulnerable people and its role in triggering long-term symptoms in some cases, it's worth testing rather than assuming "it's probably just a cold" if you have any of the more COVID-19-specific symptoms, particularly fever or a change in smell or taste.

It's also worth remembering that a cold, while generally milder, isn't entirely without its own risks for certain people, including those with underlying respiratory conditions. The precautionary principle of testing when in doubt, rather than assuming the milder explanation, applies sensibly to both directions of uncertainty.

A quick recap

Fever and loss of smell or taste lean more towards COVID-19, while a cold tends to bring milder, more localised symptoms without fever and appears more quickly after exposure. Given the significant overlap between the two, testing remains the only reliable way to know for sure, particularly if you're in a high-risk group or around someone vulnerable.

Frequently asked questions

Can you have a cold and COVID-19 at the same time?

It's possible, though relatively uncommon and testing is the only way to know if more than one virus is involved if your symptoms seem unusually severe or prolonged.

Is a sore throat more common with COVID-19 or a cold?

Sore throat can occur with both illnesses and isn't a particularly useful distinguishing symptom on its own.

Does a negative lateral flow test rule out COVID-19 completely?

Not entirely, particularly very early in an infection. If you still have symptoms after an initial negative result, testing again over the following couple of days is generally recommended.

Are children's symptoms different between a cold and COVID-19?

Children can show a similar overlap in symptoms to adults, though colds are extremely common in childhood generally, which can make distinguishing the two by symptoms alone even harder without testing.

Why does COVID-19 sometimes cause loss of smell when a cold rarely does?

Researchers believe SARS-CoV-2 has a particular ability to affect the cells supporting the smell nerves, producing this symptom more frequently and often more dramatically than the mild, congestion-related smell reduction typical of an ordinary cold.

Can allergies be mistaken for a cold or COVID-19 too?

Yes, seasonal allergies can cause a runny nose, sneezing and congestion that overlaps with both a cold and COVID-19, though allergies typically don't cause fever or body aches, which can help distinguish them alongside the pattern of symptoms recurring at the same time each year.

Is it worth testing for COVID-19 even with very mild symptoms?

Testing with mild symptoms is a reasonable precaution, particularly before spending time with someone vulnerable, even though many people with very mild symptoms would otherwise assume they simply have a minor cold and not think to test at all.