The complete guide to colds and flu

What is the difference between a cold and the flu?

Flu is typically more severe and develops quickly. If you feel unwell and then slowly get sicker over a number of days, you are more likely to have a cold. Symptoms of the flu usually come on quite suddenly and make you very ill in a short period of time. Sometimes flu can present as a mild illness that is indistinguishable from the common cold. Recent research has also revealed that people may experience “long colds”, in the form of persistent coughing, stomach pain and diarrhoea.

What makes you more susceptible to colds and flu? 

Dr Gary McLean, emeritus professor in biosciences at the School of Human Sciences at London Metropolitan University, explains that anything that reduces your immune system’s effectiveness can make you more prone to colds and flu.

“Stress, tiredness, poor diet and lack of sleep are some common factors that can suppress immunity and limit your ability to fight off infections, particularly in the early stages. But people still need to be exposed to a virus to get infected, so ultimately what makes people susceptible is putting themselves in positions where the viruses can reach them.”

How can you treat colds and flu at home?

The general advice for both cold and flu infections is to rest, sleep, keep warm, take paracetamol or ibuprofen to lower your temperature and treat aches and pains, and drink plenty of fluids to avoid dehydration. Some products, such as Vicks First Defence nasal spray, may help minimise the risk of a full-blown infection. The manufacturer says it works by trapping viruses in the back of the nose and inactivating them before they develop further along the respiratory tract into a full-blown cold. A 2022 study conducted in vitro found that another nasal spray for trapping allergens and pathogens, Bentrio, was effective at slowing Sars-CoV-2 replication on nasal tissue.

Martineau says: “There are antiviral treatments for Covid-19 and RSV but these tend to be used for people at high risk of severe complications, such as those with profound immunosuppression. The advice for those with common colds and flu is symptom management. It is also important to not give it to other people. Work from home. You are doing your colleagues a favour by staying at home and not passing it on.”

When should I go to the doctor?

Generally, colds do not require a doctor’s appointment. The NHS advises parents with babies or young children who have the flu to request an urgent GP appointment or call NHS 111 if they are worried about the symptoms. Those aged 65 or over, pregnant women and those with a long-term medical condition such as diabetes or a condition that affects the heart, lungs, kidneys, brain or nerves should also see a doctor if symptoms do not improve after seven days, as should those with a weakened immune system, for example, because of chemotherapy or HIV.

Call 999 or go to A&E if you get sudden chest pain, have difficulty breathing or start coughing up a lot of blood.

Martineau adds: “You should contact a doctor if you are getting severely short of breath or feeling extremely unwell.”

How can I prevent a cold or the flu?

McLean advises minimising contact with lots of people, spending more time outside and washing hands.

“In addition, get plenty of sleep, maintain a good diet, try not to get run down and take supplements that can stimulate the immune system,” he adds. “Try to avoid touching common surfaces and then touching your face without washing your hands. 

“Being indoors with a mixture of people and in close proximity for extended periods of time increases your chances of infection. Public transport, crowded indoor areas, mixing with lots of people, not washing your hands, all of these will increase the likelihood of exposure if someone infected is present.”

He also advises keeping vaccines up to date for Covid-19 and influenza.

There are no vaccines for the common cold, and as there are so many different viruses that cause it, people don’t get immunity in the same way that they get immunity to chickenpox or tetanus.

“The viruses are numerous and constantly mutating, and immunity is relatively short-lived in comparison to something like chickenpox,” explains Martineau.

The one exception to this rule is RSV, for which a vaccine has been trialled. Although it has not yet been approved by Nice, the Joint Committee on Vaccination and Immunisation (JCVI), which advises UK health departments on immunisation, recently issued a recommendation that the Government considers programmes of vaccinations against RSV for infants and people over 75.