Ah-choo! You're bound to hear that sound — along with sniffling, coughing, and nose-blowing — every winter when cold-and-flu season sprinkles its misery on just about everyone. Up to 20% of Americans get the flu every year, and Americans suffer one billion colds. Children get colds and the flu more often than adults. Some kids get as many as 12 colds a year, while adults average 2 to 4.
With your chance of getting a cold or the flu so high, this 10-Minute Consult on Cold and Flu will surely be useful. This report will show you how to avoid getting colds and the flu, and, if you do get sick, what you can do to feel better. You'll also learn how to treat these usually minor miseries and when to see your doctor. The report also provides specific information for high-risk groups, for whom the flu can be very serious.
What causes a cold and the flu?
A cold and the flu are both caused by viruses, tiny infectious agents that can survive only by getting inside the cells of animals or humans. One of the differences between a cold and the flu is the kind of virus that causes each. The flu, medically known as influenza, is always caused by one of the influenza viruses. Colds (also known as viral rhinitis, nasopharyngitis, or nonspecific upper respiratory infections), on the other hand, can be caused by more than 200 different viruses — and that estimate includes only the viruses doctors know about. The viruses that cause as many as 50% of colds in adults have not even been identified. The biggest offender, called the rhinovirus, causes up to 40% of colds and has about 100 distinct types. Other prevalent upper respiratory viruses include coronaviruses, adenovirus, and the respiratory syncytial virus. Your body reacts very differently to being infected by a cold virus versus an influenza virus. The type of virus determines what symptoms you get and how severe they will be.
Many cold viruses are extremely hard to grow in laboratory environments, and are therefore hard to study.
Learning more about the viruses that cause colds and the flu can help doctors figure out how to prevent and treat these illnesses. For most people, however, the most important thing to know is that viruses are to blame for both colds and the flu. This fact has very important implications for treating — and preventing — these illnesses. For example, knowing that colds and the flu are caused by viruses explains why taking an antibiotic would do nothing for you. Antibiotics work only on bacterial infections, not on viral infections.
The stomach "flu"
People often use the term "stomach flu" to describe stomach symptoms that occur separately from the flu symptoms listed in the table below. This is not an accurate term, because the influenza virus does not cause the stomach "flu"; other viruses do. That said, influenza can cause stomach problems such as nausea, vomiting, and diarrhea, but these occur along with the other, more typical flu symptoms. Stomach problems that accompany influenza tend to plague children more often than adults.
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How do cold and flu viruses spread?
The main way that illnesses like colds and the flu spread from person to person is through the droplets that sick people propel when they cough and sneeze. These droplets may get deposited on the mouth or nose of people nearby, spreading the virus to them. Germs can also be spread when a person touches a surface (like a desk, doorknob, or hand) that has droplets from a sick person on it, and then touches his or her own eyes, mouth, or nose. Some viruses and bacteria can live for two hours or longer on surfaces. Physical contact (such as kissing) with someone who has a virus will also likely cause it to spread from one person to another.
As you have probably noticed, the flu is much more seasonal than colds. In the United States, flu season is generally from November through April. During these months the flu can sweep through communities rapidly. Colds may increase in the winter, but they can hit a person at any time of the year.