Why we get sick more often in winter and autumn: Causes and ways to protect yourself

During the warmer months of the year, we seem to worry less about coughs, colds, or the flu. However, as soon as the leaves begin to yellow and the temperature drops, we start hearing more sneezes and coughs around us. Why does this pattern occur?

It is scientifically proven that most respiratory viral infections, including the common cold, influenza (flu), and Respiratory Syncytial Virus (RSV), are seasonal, peaking in the autumn and winter months. The reasons are multifaceted and relate to changes in both our bodies and the environment.

1. The Effect of Cold Temperatures

Cold weather allows viruses to survive and spread for longer.

• Increased Viral Longevity: Some viruses, particularly the influenza virus, have a protective fatty membrane. Low temperatures and dry air contribute to the hardening of this membrane, helping the virus maintain its activity for longer outside the body or indoors.
• Weakened Nasal Defense Function: A drop in the temperature inside the nose can weaken the local immune response, specifically slowing down the efficiency of mucociliary clearance (the mechanism by which cilia push viruses and bacteria out of the nasal cavity).

2. People Gathering Indoors

When it is cold outside, people spend more time in closed and poorly ventilated areas: schools, workplaces, and public transport.

• Concentration: Gathering a large number of people in close proximity significantly increases the likelihood of infection. Tiny droplets laden with viruses are easily transmitted through coughing, sneezing, or simply speaking.

3. Lack of Sunlight and Vitamin D Levels

In autumn and winter, especially in high latitudes, the amount of sunlight sharply decreases.

• The Role of Vitamin D: Our skin produces Vitamin D in response to the sun’s Ultraviolet B (UVB) rays. Vitamin D plays a crucial role in regulating the immune system. A deficiency, often observed during colder months, can weaken the immune response against viruses.

4. The Effect of Dry Air

In cold weather, the outdoor air is naturally drier, and indoors, due to the operation of heating systems, the dryness increases even further.

• Drying of Mucous Membranes: Dry air can dry out the mucous membranes of the nose and throat, which are the body’s first line of defense. Dry mucous membranes become more vulnerable to viral penetration.

✅ How to Protect Yourself

Despite the inevitability of seasonal factors, it is possible to reduce the risk of illness by following a few simple rules:

1. Hygiene: Wash hands frequently and thoroughly with warm water and soap. Avoid touching your face—especially the nose, mouth, and eyes—with unwashed hands.
2. Ventilation: Frequently ventilate indoor spaces, allowing fresh air to enter and reducing the accumulation of viruses.
3. Humidification: Use a humidifier at home to help the mucous membranes of the nose and throat maintain their protective properties.
4. Nutrition and Vitamin D: Follow a balanced diet and, if necessary (after consulting a doctor), take Vitamin D supplements.
5. Vaccination: Do not forget about the seasonal flu vaccination, which is one of the most effective means of protection.

In summary, during the autumn-winter season, we face a combination of several unfavorable factors: favorable conditions for viral survival, a certain weakening of immunity, and closer contact between people. All of this together creates the perfect environment for the spread of seasonal illnesses. By understanding the causes, we can take preventative steps to minimize the risk of getting sick.