Winter doesn’t just bring snowflakes and shorter days, it ushers in a noticeable spike in colds, flu, RSV, COVID-19, and other respiratory infections. It’s a pattern we see year after year, and it’s not your imagination: winter really is the perfect storm for illness. It’s important you understand why and what you can do to stay healthier throughout the season.

Why Infections Surge in Winter

1. Viruses Thrive in Cold, Dry Air: Cold weather lowers humidity, and that dry air lets respiratory droplets stay suspended longer. That means viruses can linger in the air and reach more people before settling.
2. We Spend More Time Indoors Together: Closed windows, tight spaces, and poor ventilation make it easier for germs to spread. Whether it’s school, the workplace, or holiday gatherings, shared air leads to shared viruses.
3. Our Immune System Slows Down: Some studies suggest our immune response dips in colder temperatures. That slight reduction makes it easier for viruses to take hold when they enter the body.
4. Shorter Days Affect Our Health: Less sunlight means lower vitamin D levels for many people. Vitamin D plays a role in immune function, so winter’s darkness can leave us more vulnerable.

How You Can Protect Yourself This Season

• Stay Up to Date on Vaccines
  • Flu shots, COVID-19 boosters, and RSV vaccines (where eligible) are some of the strongest tools we have. They don’t just reduce the chance of infection, they dramatically lower the risk of severe illness.
• Humidify Your Indoor Air
  • Keeping indoor humidity between 40–60% helps reduce virus survival and can soothe dry nasal passages, which are your body’s first line of defense.
• Wash Your Hands, A Lot
  • Frequent handwashing still works. It removes germs before they reach your eyes, nose, or mouth, especially after being in public spaces.
• Improve Ventilation
  • Open windows when you can, invest in a HEPA air purifier, or simply run a fan to improve airflow. Cleaner air means fewer opportunities for viruses to spread.
• Know When to Stay Home
  • If you’re sick, rest. Pushing through only spreads germs and slows your recovery. When in doubt, test for respiratory infections like flu or COVID-19, early detection helps guide treatment.
• Lean Into Healthy Habits
  • Sleep, nutrition, hydration, and activity all strengthen your immune system. Even small steps: a brisk walk, a balanced meal, or an extra hour of sleep make a real difference.

The Bottom Line

Winter may stack the odds in favor of infections, but small, practical steps can dramatically reduce your risk. With good prevention, timely vaccination, and a little attention to your indoor environment, you can protect yourself and the people you care about all season long.

Curran Perry, M.D., is with UPMC Infectious Disease and sees patients at UPMC Williamsport, 700 High St., Williamsport. To schedule an appointment with Dr. Perry, call 570-321-2181. For more information, visit UPMC.com/NorthCentralPa.