What arrives with winter holidays? The cold season! Not just cold weather, but the viruses and bacteria that make people sick more frequently with colds and flu. Did you ever wonder why people get colds when it gets cold? While those “bugs” are around all year, people tend to encounter them more often and in greater concentration at this time of year due to a more active holiday social schedule that tends to be indoors. Unfortunately, gifts and food aren’t all that get shared at those events. (Intriguingly, there’s also evidence that cold air may reduce the effectiveness of the nasal immune response that fights viruses and bacteria.(1))
Viral Infections
To make you sick, viruses have to get into your body. That happens in three ways—through the air into your sinuses and lungs, through food and drink into your digestive system, and through breaks in your skin. Fortunately, public health systems have substantially reduced our daily exposures to infected water or food sources, so these days by far the most common method of virus transmission and entry is through the air or touching an infected person or object.
Over 200 virus species have the ability to infect humans. Every type of virus is a tiny package of genetic code. It is not alive. In a viral infection, a virus invades a living cell, hijacks the cell’s protein-printing machinery, and produces thousands of copies of itself.
Nearly all airborne viruses are sensitive to elevated temperature, which inhibits the virus’s ability to replicate. So to fight a viral infection, one type of white blood cell (lymphocyte) produces chemical messages that raise the temperature. Another immune response is production of excess mucus, which adds a layer of liquid protection. The mucus also creates an inhospitable environment for some viruses and provides a convenient (if unappealing) medium for transporting the virus out of the body.
Generally, a fever and increased mucus production are signs that the immune system is responding appropriately to a viral infection. Typically, however, a viral fever is not high. If a high fever develops after a few days of a viral infection, it may be due to a bacterial infection that took advantage of the cellular damage created by the virus.
Bacterial Infections
Bacteria are everywhere. Beneficial bacteria are in foods such as yogurt and kombucha. Bacteria are harmful when they live in the wrong place, when they grow uncontrolled, or when the concentrations of beneficial bacteria are reduced. Harmful bacteria that grow in the dirt are only harmful when they start growing in a skin injury. Bacteria that is normally harmless in the digestive tract can cause an infection in the urinary tract. When helpful gut bacteria are killed off, other gut bacteria invade the now-available digestive real estate. Basically, our bodies have evolved to live in an environment full of bacteria and we use bacteria to maintain health. Imbalance and infections occur when bacteria can grow uncontrolled in the wrong place.
Unlike viruses, bacteria are living things. Their body is one cell, roughly 10-100 times larger than a virus. They have their own genetic material, consume nutrients for energy, produce wastes, and can replicate themselves.
To render bacteria (and viruses) inactive, your white blood cells (lymphocytes) produce structures called antibodies, which are designed to attach to the bacteria (or virus) to neutralize it. If your body has experienced the same “bug” in the past, your white blood cells will launch a precision attack against the bacteria or virus by producing the type of antibody that specifically targets the “bug”. As part of your recovery, your body makes and stores a record of the antibody in your immune system’s library so it can be more rapidly produced in case of future infection by the same bug.
For larger, deeper, more serious bacterial infections, the immune system may trigger a high fever, which has long been known to inhibit the growth of certain bacteria. (In fact, prior to the availability of antibiotics, doctors treated certain infections by raising the patient’s temperature artificially. (2))
Treatments: Antibiotics and Fever Reducers
Many antibiotics are derived from fungi. That’s because fungi in the soil compete for the same nutrients as bacteria, so successful fungi have developed bacteria-killing mechanisms that scientists harnessed to create antibiotics. Antibiotics fight bacterial infections only; they do not work on viral infections.
Fever reducing medicines may make you feel more comfortable and keep fevers from getting dangerously high, but they do not cure infections or help you heal faster.
Staying Well
There are two general effective strategies for avoiding viral and bacterial infections:
- Keep your immune system strong. Healthy food, enough high-quality sleep, and regular physical activity are the basics. You’ll never know how many infections you didn’t get because your immune system was working as it should.
- Prevent transmission. Wash your hands frequently during cold and flu season (soap destroys both viruses and bacteria). Consider wearing a high-quality mask when you are sharing air indoors in a group. Most importantly, avoid contact or proximity with others if you are sick. After all, there’s no reason to spoil their holiday, too!
