The reason you’ve got a cold that won’t go away

Coughs, sneezes and sniffles are a sure sign that winter has come, and once they take hold they can be hard to shift. This year, many of us are wrestling with colds that are still hanging around even after a month – no matter how much Lemsip we drink or rest we get.

Why is it that a good night’s sleep and plenty of fluids is enough to crush a cold some years, while at other times they drag on into the spring?

A common cold should usually clear up after seven to 10 days, “but it’s not uncommon for symptoms like coughs and congestion to linger for up to several weeks post-infection,” says Dr Semiya Aziz, an NHS GP and founder of private healthcare service Say GP. No wonder, then, that the average person takes about six days off from work because of minor ailments each year.

The illnesses circulating this winter seem to have been caused by “the usual basket of winter viruses”, according to Ian Jones, a professor of virology at the University of Reading. But a combination of exhaustion, a weakened immune system and the worst flu season seen in years could well be behind your extra-long cold.

What causes a cold?

Common colds are caused “by a dozen or more different viruses, which all infect the upper respiratory tract, so the back of the throat and sometimes the lungs,” Prof Jones explains. “Those viruses kill the cells that they infect, and with those cells not there to function properly, your throat becomes sore and you can’t clear mucus from your throat and nose.”

Not everyone who comes into contact with a cold virus will be infected by it, and some people can become infected more severely than others. Both factors depend on “your level of natural immunity to that specific virus and the amount you’re exposed to,” Prof Jones says.

Colds come around each winter for a reason. “During the winter, we all tend to meet inside and spend time in close contact there, where it’s easier for viruses to circulate,” says Prof Jones.

“Coupled with the fact that cold viruses are much more stable in cold weather than in heat, it’s easy to see why many more of us catch colds while it’s cold outside,” Prof Jones adds.

On top of that, “colder weather commonly weakens the immune system,” says Dr Aziz. At this time of year, “people become far more susceptible to respiratory illnesses such as cold, flu and pneumonia”.

Why is my cold hanging around?

There are a number of reasons why people have reported that their colds are lasting for longer this winter. For one, this is only the fifth winter since Covid-era lockdowns began, a fact that Dr Aziz says may still be impacting our susceptibility to colds.

“The limited exposure to viruses during lockdowns may have potentially weakened our immune defences, reducing the level of residual immunity that we have and predisposing us to the current viral infections,” she explains.

There’s also the fact that “some cold viruses have a greater propensity than others to make their way into your lower lung regions, which can give you bronchitis rather than just a sore nose and throat,” Prof Jones says.

“These infections do go on longer than others because the cells that get damaged take longer to repair. A lot of that is related to what precisely the infection was.”

It may also be that you never had a common cold in the first place. While rhinoviruses are usually to blame for common colds, “seasonal varieties” of coronaviruses could be to blame for your cough and fever, Dr Aziz says, as well as respiratory syncytial virus or RSV – which cause cold-like symptoms in most people and can last for up to a fortnight. Cases of RSV have been much higher this winter than in other years.

Cases of HMPV, a flu-like virus circulating in China, have also been found in the UK, and this illness can linger for up to a fortnight. HMPV may cause cold-like symptoms “but this should not be seen as a serious risk to your health, because we all have natural immunity to it,” says Prof Jones.

At the same time, those dozens of cold-causing viruses “are constantly changing and mutating, allowing them to survive longer in the environment,” says Dr Aziz. “This may lead to more severe or prolonged symptoms” and in other cases “exposure to a second virus can occur during recovery, leading to new symptoms.”

There are also lifestyle factors that can “depress the immune system” and leave us more vulnerable to colds, too: “stress, inadequate sleep and poor nutrition” can all leave us more susceptible to illness or impede our recovery from coughs and colds, says Dr Aziz.

What can you do?

“Basic lifestyle measures are the first port of call for a speedy recovery,” Dr Aziz says. Resting, eating well and getting enough sleep should mean that your cold doesn’t drag on.

“It’s important to hydrate, drinking plenty of fluids, including warm soups or teas,” she explains, with this preventing your airways from becoming too dry, helping to stop a build-up of mucus. “Rest helps the body to recover and repair, and a healthy, varied and balanced diet rich in vitamins and minerals can help to shorten the illness and aid recovery.”

When to see your GP

Dr Aziz advises that you see a doctor “if there is a high fever, above 39C, or a lower fever for several days in a row”. Other reasons to seek medical help are symptoms such as “severe sinus pain, earache, swollen glands, shortness of breath or wheezing”.

Prof Jones adds that you should see your GP if your cold is “unduly long”, meaning that your symptoms have not improved at all for 10 days, particularly if you have a fever that has not gone down.

Should I take antibiotics?

Antibiotics won’t work to treat a cold. This is because “colds are caused by viruses rather than bacteria,” Prof Jones says, “so antibiotics won’t target the source of your symptoms”. This includes viral pneumonia, which can occur when a cold virus makes its way to your lungs, causing an infection that can last for up to six weeks in some cases – so that very long “cold” could be pneumonia.

Having a bad cold can also make your body more vulnerable to bacterial pneumonia, which can be caught from someone who already has the illness and lasts for a similar stretch of time. Antibiotics are regularly prescribed for bacterial pneumonia.

The symptoms of pneumonia include chest pain, a fever, confusion, and a cough that brings up yellow, green or bloody mucus. It’s important to see a GP if you believe you may have pneumonia, to get antibiotics, as the illness can become serious.

For those without these symptoms, “over-the-counter remedies may provide temporary symptomatic relief,” Dr Aziz says. “Painkillers, decongestants or lozenges can help you feel better in the short term, while humidifiers prevent the mucous membranes in your airways from drying out and potentially shorten the duration of illness.”

Will vitamins help?

Unfortunately, hard evidence for whether supplements can help you to get over a long cold is lacking. “As long as you’re eating a healthy diet, supplements really don’t do any good when it comes to preventing or cutting short a cold. Claims of this are anecdotal and not supported by the evidence,” says Prof Jones.

“Maintaining a varied balanced diet, rich in fruits, vegetables and whole grains is the best way anyone can help to support their immune system,” agrees Dr Aziz. That said, “supplementation can be considered when dietary intake is insufficient or specific deficiencies have been identified”.

For that reason, “regular vitamin C and zinc supplementation may still help to reduce the duration and severity of a cold. Vitamin D helps to boost overall immunity and may reduce the risk of respiratory infections, but doesn’t stop you from getting a cold”.