Flu, or influenza, blankets the U.S. and most of the world in sickness every year. The flu is an annual source of major medical concern, as the very young and old, as well as those with a weakened immune system, can develop fatal complications arising from a bout of influenza. For this reason, it is critical that families with young children, as well as the elderly, keep a close eye on flu outbreaks and any sign of infection in a high-risk individual. Early intervention can often make a difference, so do not hesitate to visit a healthcare provider if influenza is suspected to any degree.

What are the symptoms of the flu?

Symptoms of influenza are, at first, almost impossible to distinguish from the common cold. Their symptom profiles are very similar, but there are some notable differences. Here are the signs of someone coming down with the flu:

  • Chills or a chilling sensation – This is often the first sign of the flu, though it doesn’t always present in those affected.
  • Fever – A fever also presents early on, and it can increase in severity quickly.
  • Muscle aches
  • Cough
  • Nasal congestion
  • Sore throat
  • Fatigue
  • Headache
  • Runny nose
  • Ear pressure or earache
  • Diarrhea, vomiting or abdominal pain

That is a long list of symptoms, and many of them are like the symptoms that come with a cold or upper respiratory infection. However, the flu and the common cold progress at different speeds, which can help an observant patient make a good guess as to what they have. For example:

  1. The common cold sets in slowly, while the flu does not – People who pick up a cold often know they are getting sick well before they start showing the worst symptoms. In some cases, this could be a day or more. The flu rarely gives that much leeway, as the onset of symptoms are rapid, often within hours.
  2. The flu almost always presents with a fever – Influenza brings with it a rapidly progressing fever that usually produces temperatures in excess of 100 degrees Fahrenheit. A cold, though, frequently occurs with no fever at all, and if a fever is present, the temperature typically remains in the low-grade zone. In the unusual event that a cold results in a higher fever, the patient’s temperature will usually rise gradually.
  3. The flu feels more aggressive than a cold – Anyone who has the flu knows that it doesn’t behave like a cold. Everything about the flu is more severe. The symptoms are of a greater severity and the malaise that accompanies the symptoms feels worse. Where most healthy adults can maintain many of their daily activities while suffering from a cold, the flu puts most people in bed, no matter how healthy they are otherwise.

Why is the flu so dangerous?

The flu may seem like a really bad cold, so why is it so much more concerning? There’s two reasons. For one, it is constantly mutating, which makes it difficult to treat and control. Influenza is categorized into three subtypes – influenza A, B and C. Influenza B and C are relatively minor compared to subtype A, as they mutate so slowly that humans can build immunity to them from an early age. They can also be treated with much greater efficacy.

Subtype A, though, is constantly changing, either by mutation or genetic re-assortment. Influenza A possesses this ability partly because it can infect more than just humans, including birds and swine. This gives the virus additional resources in changing itself to stay ahead of the human immune system and our ability to fight the virus. It is this rapid ability to change that keeps the flu vaccines from being as reliable as other vaccines.

Because the flu virus is just a little different every season, it can produce an annual epidemic, though when the virus is only a little different, many people retain resistance to it. However, every few decades, influenza undergoes a major re-assortment and antigenic shift, which means very few people, if any, harbor resistance to the virus. When this occurs, a deadly pandemic is possible. The Spanish flu of 1918, for example, infected 500 million people globally and killed between 50 and 100 million.

Another reason influenza is so dangerous is because it is particularly virulent. Without a reliable way for the body to resist it, influenza subtype A can overwhelm people in high-risk categories, including the very young, the elderly and those with other medical complications.

Should I get the flu vaccine?

The flu vaccine may not be perfectly reliable, but it is safe and can provide a significant degree of resistance. Because the vaccine must be synthesized before the onset of the flu season, researchers have to forecast which variety of influenza will be predominant when it arrives. Though epidemiologists have sophisticated tools in predicting the spread of influenza, some strains of influenza are easier to vaccinate against than others due to how the virus spreads and how inactivated versions of the predominant virus can be used to produce a vaccine. In other words, some strains of influenza are easy to capture for the purposes of vaccination, while some are much more difficult to preserve.

During a typical flu season, the vaccination can reduce flu cases by up to 60 percent, according to the U.S. Centers for Disease Control and Prevention. Receiving the flu shot is a major boost to a person’s chances of avoiding the virus. And even if the vaccine does not prevent infection outright, it can reduce the severity of symptoms, as the vaccine primes the body to recognize and fight the virus.

People in high-risk segments of the population should be administered the vaccine with few exceptions. Children as young as six months of age can receive the vaccine safely.

What if I have the flu?

Unfortunately, once someone catches influenza, there are few options for treatment. Because it is a virus, antibiotics have no effect on it, and though some antiviral drugs may help if the flu is caught early, they are inconsistent and are often resisted by the virus. With these considerations, the best defense is protection via the flu vaccine.

If infected with the flu, get in bed and get lots of rest. Drink fluids and manage the symptoms with over the counter pain relievers and fever reducers. However, do not administer aspirin to children with fly symptoms, as this can result in a serious complication known as Reye’s syndrome.

Those who contract the flu, especially those with young or elderly in the home, should do their best to limit contact with others to prevent its transmission. A healthcare provider can verify if a patient has influenza or another illness, which can help determine the best course of action.

Influenza is so ubiquitous that people often forget just how debilitating, and even deadly it can be. Anyone who suspects they have the flu should visit their healthcare provider for a confirming diagnosis.