Flu season is underway, and plenty of people are dealing with this highly contagious virus.
Influenza typically spreads via coughs and sneezes from an infected person. Infected adults can spread the virus one day prior to noticing symptoms and up to a week after symptoms begin. Although most cases of the flu tend to go away by themselves, estimates from the U.S. Centers for Disease Control and Prevention (CDC) indicate as many as 82 million people get the flu annually. Up to 130,000 people died from the illness, and around 1.3 million people were hospitalized during the 2024-2025 season.
Here's why we are more prone to viruses during the cold winter months of the year.
Why viruses love the cold
The CDC monitors flu activity very closely. Flu season can begin in the U.S. as early as October but does not usually kick into full gear until December and typically peaks in February. Influenza can occur at any time, but most cases follow a predictable seasonal pattern.
It is a common misconception that the flu is directly caused by cold temperatures. However, the influenza virus is necessary to have the flu, so cold temperatures are only a contributing factor, although some argue it is the lack of sunlight or different lifestyles people lead in winter months that are the primary contributing factors.
Common cold and flu viruses attempt to enter our bodies through the nose, but our nasal linings have strong defense systems that protect against these microbial intruders. In a 2016 study, researchers found that viruses were more likely to die in the immune system when grown at warmer temperatures.
Cold air, on the other hand, cools the nasal passages and slows down mucus clearance, allowing the virus to infect the body.
Additionally, during the cold winter months people tend to spend most of their time indoors with the windows shut. This often means in public places, viruses can spread more easily from one person to another when we're in close contact -- such as school settings, for example.
How to protect yourself from the flu
Here are a few tips to avoid becoming infected with the flu:
- Get vaccinated: The annual flu shot is the most effective way to protect yourself against the flu and other serious complications.
- Wash your hands regularly. Clean hands protect against many infections, including the flu and COVID-19. Keeping your hands clean is an easy way to keep yourself and your loved ones healthy.
- Avoid touching your eyes, nose and mouth. Germs are most likely to enter your body through the eyes, nose and mouth. Although we cannot control everything we inhale, we can reduce the risk of infection by keeping our hands away from our faces.
- If you do not feel well, stay home. If you are experiencing any symptoms of the flu or COVID-19, spending any amount of time around others puts them at risk of infection. Quickly isolating yourself can prevent the spread of the flu and COVID-19 and save lives.
Although many factors can contribute to contracting a virus, cold weather presents ideal conditions to for the virus to infect people at a higher rate. Talk to your primary care provider if you have concerns about your health or have questions about your symptoms.
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