Is it a cold or Covid? How to tell the difference now the main symptoms are so similar

cold vs covid vs flu how tell difference symtptoms -  Image Source/ Getty
cold vs covid vs flu how tell difference symtptoms - Image Source/ Getty
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A cough, a fever or shortness of breath: back in March last year, these were the three symptoms that the government warned us to look out for which could be signs of Covid-19. As time went on, our understanding of the virus changed, and loss of smell or taste were added to the list.

Now, however, the list of the “classic” symptoms appears to be somewhat out-of-date for sufferers of the Delta variant, which originated in India. At the moment, the NHS says that a temperature, cough or loss of smell or taste are the main signs of Covid, but none of these feature in the top three most common symptoms in people with the virus in the UK.

"This variant appears to be working slightly differently," said Prof Tim Spector, lead scientist on the Zoe symptom tracker app in a video on YouTube. "We don’t even see loss of smell coming into the top 10 [most common symptoms] anymore."

The Indian variant appears to be mostly affecting people who have not yet got both vaccinations, who tend to be younger and have milder symptoms. This might be making it harder to distinguish between a cold and Covid – which can fuel the rise of the new variant as people don’t think they need to get tested.

"Covid is acting differently now: it’s more like a bad cold in this younger population," said Spector. "This means that people might think that they’ve got some sort of seasonal cold and they still go out to parties and they might spread it around to six other people. We think this is fuelling a lot of the problem."

For people with milder symptoms, it can be difficult to work out the difference between coronavirus and ordinary colds. This is a task that’s even harder in the spring and summer, when a tickly cough or runny nose could be signs of hayfever, too.

What are the main symptoms of Covid now?

According to the Zoe app, developed by researchers at King’s College London, the most common symptom of Covid at the moment is a headache. It is incredibly common: two-thirds of the under 40s currently suffering from the virus have a headache and over half of those over 40.

The next most common symptoms are a sore throat and runny nose – classic features of a common cold. Half of those under 40 report a sore throat or runny nose and about a third of the over 40s feel the same.

For the over 40s with the virus, none of the “classic” symptoms named by the NHS makes it into the top five most common signs of the virus. Four in 10 people under 40 report either a fever or persistent cough.

How do I know if I have Covid or hayfever?

Having a high temperature (over 38C or 100.4F) is a common sign of a cold or Covid, but is unlikely to be hayfever. If you have red, itchy or streaming eyes, you are much more likely to have hayfever than a viral infection like a cold or Covid.

Both Covid and hayfever can cause loss or change of smell or taste, but each condition may feel a bit different. With hayfever, a stuffy nose will be the cause, but a loss of smell or taste without a blocked nose is more common with Covid.

Hayfever and other allergies can cause a scratchy feeling in your throat. Sore throats are also common in Covid or colds but are more likely to feel painful rather than itchy.

How do I know if my headache is a cold or Covid?

According to Zoe, a Covid headache has particular features that mark it out. They are typically moderate to severe: lasting for three to five days on average and don’t feel better after using painkillers. They are also generally felt on both sides of the head and could feel like they are “pulsing”, “stabbing”, or “pressing”.

Headaches tend to be one of the first signs of Covid but can linger for a while in people with long Covid. Around 15 per cent of people with Covid have a headache as their only symptom.

How do I know if my runny nose is Covid or a cold?

A runny nose can be caused by the common cold or by Covid-19. Getting a runny nose caused by Covid is much more likely when rates of the virus are high in the population at large, like they are now. When rates are lower, it’s more likely to be caused by other conditions, like an allergy or a cold.

What should I do if I don’t know if it’s a cold or Covid?

Unfortunately, despite the “classic” symptoms no longer being the most common, the government is only giving away free PCR tests to people with a fever, loss or change in smell or taste or a new, continuous cough.

Spector says that given the changing nature of the illness, people should get a test even if their symptoms are milder or seem more like a cold. “Do stay at home and get a test,” he said, recommending people who think they may have a cold get a lateral flow test from their nearest pharmacy.

“If it’s positive, get a PCR test to make sure, but treat it as if you've got Covid,” he said.