The average adult will experience 2-3 bouts of the common cold a year, and as winter is in swing, the likelihood of getting sick increases.
It’s been thought for years that cold and flu viruses are more prevalent because of chillier temperatures, causing people to stay indoors more often. Being indoors more often means repeatedly coming into close proximity of your family and friends, allowing viruses to transfer from one person to another more easily.
Nevertheless, new research has been published from a team in America, Massachusetts that suggests there may be other reasons why your chances of getting sick are increases once temperatures start to drop.
How viral infections infect you
The nose is most often the entry point for viruses into human body. Virus particles can enter the nose via inhalation or through direct touch.
The nose is one of the first points of contact between the outside world and the inside of the body. Once virus particles enter the nose, the cells located in the nasal cavities rapidly activate to begin expelling them. However, new research has found evidence that cold temperatures significantly weaken this immune response.
Once a virus enters the nose, what happens?
To understand what happens when a virus enters the nose, we have to look at a study conducted by a team of scientists from Massachusetts Eye and Ear University. In 2018, the team found that when nasal cells located at the front of the nose detect bacteria, it prompts the release of billions of tiny fluid filled sacs.
Known as EVs or extracellular vesicles, the sacs quickly move into the mucus to surround and attack the detected bacteria before it has a chance to infect any cells.
Because of this finding, the team were encouraged to look further into what happens when a virus enters the nose. As a natural continuation, the team investigated whether this same response would happen to some of the viruses that cause common upper respiratory infections.
The conclusion to their study, testing three of the common cold viruses, found that the EVs released and responded in the same way as they did to the bacteria: surrounding and attacking the virus particles located in the mucus.
They found that the sacs released by the nose contain molecules, which are responsible for killing the virus. Essentially meaning the EVs were cleaning up the viruses before they had a chance to bind to the nasal cells and begin the process of infection.
How cold weather impacts this nasal response
Not stopping, the team hypothesized that because colds and flu are more common in winter, the nasal response may be hindered by cold air.
With this idea, they took nasal tissues and exposed it to temperatures of 4.4° C, and in doing so led to the tissue temperature decreasing about 5° C, consequently effecting the immune system.
Dropping the temperature had significantly reduced the immune response in the nose.
The number of recorded EVs that were released decreased by over 40%, while their quality was also severely reduced. This reduction in response provides the virus with an easier time sticking and infecting the nasal cells. Once stuck, they remain and start dividing, and infecting.
As reported by their team, this is one of the first biological explanations why people are more likely to develop upper respiratory infections in colder temperatures.
Recognising cold symptoms and your susceptibility to infection
Dissimilar to other viruses, cold-related symptoms classically occur in one area: the nose.
The most predominant signs of a cold are:
- Stuffy and runny nose
- Postnasal drip
The latter may also lead to a sore throat and cough. Furthermore, some people may experience other systemic symptoms, such as a mild fever or general fatigue.
Although no one is immune to cold or flu germs, there are groups of people who exist, whose bodies are unable to put up adequate defences. Due to this, they may experience complications or more severe symptoms.
These groups include:
- Young children, as their immune systems are still developing
- People who work or live in dense, highly populated areas
- Individuals diagnosed with decreased immune system function
- Cancer patients
- People who have undergone transplants
Bolster your immune system and protect yourself
Several doctors certified in allergies and immunology say that getting enough vitamin C may help bolster nasal defences. Vitamin C has been shown to enhance the mucus membranes located in the nasal passages, as well as overall immunity.
Regular Vitamin C intake acts as a powerful micronutrient, antioxidant, and cofactor for the body’s enzymes. By providing the body’s enzymes with help, innate immune cells, such as white blood cells, can operate optimally.
In general, regular Vitamin C intake will help support immunity in every part of the body that has a dense network of immune cells and tissues.
Vitamin C is readily available in various foods such as oranges, broccoli, and red peppers.
Other steps to stay healthy
Aside from getting the recommended daily Vitamin C intake, basic hygiene measures can also protect you from getting sick. These include:
- Hand washing
- Hand sanitizing
- Wearing a high-quality face-mask (especially in crowded spaces)
- Covering your mouth while sneezing or coughing
- Isolating when sick
The research team hopes that the study helps provide a better understanding how our bodies react to viruses in different environments, and exploring possible treatments.
One such treatment could involve a nasal spray that bolsters the innate immune response inside the nose or increase the number of vesicles.
Whilst these hypothetical treatments are still being researched/developed, stick to measures such as taking Vitamin C or wearing a mask in crowded spaces in order to defend your nose.