About cold and flu viruses
Cold and flu are respiratory illnesses – meaning they can affect your nose, throat and lungs. They’re both caused by viruses. The viruses responsible for the flu are called influenza viruses, while those most commonly responsible for a cold are called rhinoviruses. There are three types of influenza viruses (A, B and C), and over 200 viruses which can cause colds. You can get a cold or flu if you come into contact with one of these viruses, often from someone else who is already infected.
If you catch a cold, you might find you have a mild temperature, sore throat, blocked or runny nose, and are sneezing or coughing. If you get the flu on the other hand, your symptoms are likely to be more severe. As well as the symptoms of a cold, you might also have a headache, fever, the shivers, feel aches and pains, and need to stay in bed for a few days. Although you can get a cold or flu at any time of year, here in the UK, they’re much more common during the winter months.
Why are cold and flu viruses more common in the winter?
While you can’t become ill simply by feeling cold, it is a contributing factor for a number of reasons.
We spend more time together indoors
When it’s cold outside, we naturally tend to gather indoors to stay warm. But being in close proximity with one another during the winter months means viruses can spread easily from person-to-person. They can move through the air in droplets when you sneeze or cough, be spread by hands, and live on contaminated surfaces like keyboards and door handles. Places like public transport, schools and the workplace are the perfect breeding ground for viruses. So being in close contact to one another during the winter months makes it easier for these viruses to get around.
Some viruses thrive in winter conditions
Some research has found that the viruses responsible for cold and flu can survive and multiply more easily in conditions that are cold and dry with little sunlight. And that they may not be as efficient at making you sick if they’re warm. It’s also been suggested that the droplets of water in the air that contain viruses (for example, from coughing and sneezing) can stay in the air for longer if it’s dry.
Your immune defences may weaken when it’s cold
Your immune system is the complex system of your body that protects you from disease. Some studies have suggested that the cold and dry conditions of winter could make it harder for your immune system to fight off harmful viruses. For example, interferons are a group of proteins produced by the cells of your immune system in response to a virus. They stop these viruses from replicating. One study found that your immune system produces less of these protective proteins when it’s colder, making you more susceptible to getting ill.
As well as this, the mucous and tiny hairs that line your nose and throat are part of your body’s immune system. They act as a barrier by trapping harmful invaders that you breathe in and propelling them out of your body. Your mucous also contains antimicrobial substances that help to protect you from disease. But breathing in cold, dry air during the winter months can affect the mucous lining your nose and throat. It also reduces the supply of blood and immune cells to the area, making it easier for harmful viruses to invade your body.
So if you do come into contact with a virus during the winter months, your body’s defence mechanisms may not be as efficient at fighting it off if you’re cold.
Tips to stay healthy in winter
More research is needed before we can fully understand the relationship between the cold weather and respiratory illnesses. But for now, there are some things you can do to help keep yourself healthy during the winter months.
Adopt good hygiene
You can help prevent the spread of winter bugs by practising good hygiene. Cover your hands and mouth with a tissue when you cough or sneeze and put the tissue in the bin straightaway. Wash your hands thoroughly with soap and warm water and regularly disinfect surfaces. And avoid touching your eyes, nose or mouth in case your hands contain any germs.
Get the flu vaccination
Getting the flu vaccine can reduce your risk of getting flu. It’s important to have the vaccine each year, as it changes annually to try and match the dominant strain (type) of virus for that year.
Practise healthy habits
Living a healthy lifestyle supports your immune system and helps fight off any germs you might come into contact with. Eat a healthy diet, get enough sleep, keep your stress levels to a minimum, exercise regularly and don’t smoke.
Consider taking a vitamin D supplement
Your body makes most of its vitamin D from sunlight, and it’s also found in oily fish, eggs, meat and fortified breakfast cereals. But during the winter months, the lack of sunlight makes it difficult for your body to make the vitamin D it needs. And not getting enough vitamin D can make your immune system more susceptible to infection. In the UK, it’s recommended that all adults and children over the age of one should consider taking a daily supplement of 10 micrograms of vitamin D during autumn and winter.
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