How to spot the difference between a common cold and winter flu

As pressure mounts in government around the potential junior doctors’ strike next week, concerns are growing over the rising cases of flu across the country.

An average of 2,660 flu patients were in hospital in England each day in the week to December 7, including 106 in critical care – up 55% from 1,717 the previous week, when 69 were in critical care, according to the latest NHS England figures.

But with colds also circulating widely during the winter months, how can you tell which illness you’re dealing with?

Here is some advice on how to spot the key differences to help you safeguard your health and keep your family well through the colder months.

What causes flu and what causes a cold?

Colds and flu are both respiratory illnesses but are caused by different viruses.

“Colds are primarily caused by viruses, with rhinovirus being the most common culprit,” says Dr Naveed Asif, GP at The London General Practice. “Whereas, the flu is specifically caused by influenza viruses, primarily types A and B.”

Therefore, it’s possible to have a cold and flu at the same time.

“It is possible to be infected with both a cold and the flu simultaneously, as they are caused by different viruses,” says Asif. “Both have peaks during the cold season and can run your immune system down, making you susceptible to further infections.”

Are they both contagious? Does flu and a cold spread in a similar way?

“Both the common cold and the flu are highly contagious respiratory illnesses spread through direct contact and respiratory droplets,” says Asif. “Transmission occurs when virus-laden droplets are expelled during coughing, sneezing, or talking, landing in the mouths or noses of nearby individuals. In poorly ventilated situations, these droplets can travel longer distances.

“Infection can also occur by touching contaminated surfaces and then touching the face.”

What are the main symptoms of a common cold and flu? What are the key difference to look out for?

“A common cold usually causes a runny or blocked nose, sneezing, a sore throat, mild cough and mild fatigue,” explains Dr Claire Agathou, GP and co-founder of the A–Z General Practice at The Wellington Hospital, part of HCA Healthcare UK. “Meanwhile, flu typically causes a sudden onset of fever, severe tiredness and weakness, muscle and joint aches, a headache, a dry cough, chills (feeling shivery and sweats), a loss of appetite and sometimes diarrhoea.

“The key difference is that flu tends to come on suddenly and much more severely, whereas cold symptoms are milder and develop more gradually.”

Can a cold or flu lead to other illnesses or complications?

“While colds are usually mild and self-limiting, both colds and flu can lead to complications such as sinusitis, ear infections, chest infections, and worsening of underlying health conditions,” says Agathou.

“Flu can cause pneumonia, hospital admission, and serious illness in vulnerable groups. However, even those who are normally well can become very unwell so it’s important to contact your GP promptly to discuss your symptoms if you feel unwell or are concerned about your symptoms.”

Is flu treated and managed in a different way to a common cold?

“Both are mainly managed with rest, fluids and symptom relief such as paracetamol,” says Agathou. “However, in higher-risk groups, antiviral medication may be prescribed for flu if started early.

“Antibiotics are not effective for either unless there is a secondary bacterial infection.”

Is the recovery period usually longer for a cold or flu?

“A cold usually settles within seven to 10 days, but flu recovery often takes one to two weeks, with fatigue sometimes lasting longer,” notes Agathou.

Can the flu and colds be prevented in similar ways?

“The single most effective protection against flu is the annual flu vaccine, particularly for vulnerable groups, but other preventive steps for both flu and a common cold include regular handwashing and staying home when unwell,” advises Agathou. “I’d also recommend avoiding touching the face, covering any coughs and sneezes and making sure indoor spaces are well ventilated.”

Who is eligible for the flu vaccine in the UK?

“The free NHS flu vaccine is offered annually to adults aged 65 and over, pregnant women, children aged two-three years and school-aged children (reception years to Year 11), people aged six months to 64 years with eligible long-term conditions, people with learning disabilities, carers, frontline health and social care workers, and care home residents and staff,” says Agathou. “Household contacts of immunocompromised individuals are also eligible.

“However, people who are not eligible for a free NHS vaccine can still access the flu jab privately. If you are unsure, speak to your GP or local pharmacist.”