Influenza is a respiratory infection that can last approximately one to two weeks. It is very contagious and symptoms can range from mild to severe. Commonly known as “the flu,” it typically occurs during Flu Season which generally ranges from October to May in the Northern Hemisphere. Most people can overcome the virus, though those who have health issues may not be able to do so as easily.

What causes influenza?

Influenza is caused by a virus, a microscopic infectious entity that requires a living host to multiply and survive. Some viruses, like influenza, can survive outside of the host for 24 to 48 hours on hard surfaces, while other viruses cannot. Influenza is an easily adaptable virus that mutates or changes frequently, preventing immunity from the disease. The common strains like Influenza A and B transform quickly and are different each season. A slight change makes it hard to stop the virus from returning.

The body can develop antibodies as a natural defense against the virus if it has been exposed. However, due to how quickly the virus changes, the antibodies may not be able to fight off the new strains of the virus. Depending on how similar the strains are, antibodies may only decrease the severity of the illness rather than prevent it. Antibodies also decrease as time passes.

Viruses are not like bacteria in that antibiotics cannot kill them. Antibiotics are used to treat many illnesses; however, they have no effect on viruses and in some cases can worsen illness. Antiviral medications have been developed to treat some viruses by preventing them from reproducing. These medicines do not treat the symptoms caused by the virus and might only decrease the overall length of time that the virus stays in the body. For this reason, vaccines are used to prevent viral infections. It is important to know that vaccines may completely prevent or make symptoms less severe while still providing protection.

Who’s at risk?

People of any age can get influenza and most people are able to fight it without much difficulty. Unfortunately, some people are not able to as easily. High-risk patients include:

  • Children under 5, especially infants under 6 months
  • Adults over 65
  • People with chronic illnesses like lung disease, heart disease, diabetes, etc.
  • Pregnant women
  • People with weakened immune systems
  • People with obesity - body mass index (BMI) of 40 or more
  • People living in long-term care or residential care facilities

When people who are high-risk get influenza, they are less capable of fighting the virus than healthy people. Their bodies are in a weaker state and are often unable to stand up to the challenge. This can be a risky situation.

Symptoms of Influenza

Influenza is a respiratory illness – affecting the nose, sinuses, throat, and lungs. It spreads through the air when someone with the infection coughs, sneezes, or talks and it enters through the mouth, nose, or eyes of another person. The virus starts growing two to four days before symptoms develop and can spread as early as one day before. Symptoms include:

  • Fever
  • Chills and sweats
  • Runny or stuffy nose
  • Sore throat
  • Cough
  • Shortness of breath
  • Headache
  • Body aches
  • Generalized weakness
  • Fatigue/tiredness
  • Increased heart rate
  • Watery eyes

Note that symptoms do not include vomiting and diarrhea. These are not symptoms of influenza though they are often mistakenly called “the flu,” which is a stomach virus but not the same illness. Small children may suffer from diarrhea as it often relates to sinus drainage. This is uncommon in adults or older children.

Diagnosing Influenza

Your healthcare provider can diagnose influenza based on physical exam and symptoms. Testing may be done to confirm or determine which strain is present but is not required. The test consists of swabbing deep inside the nose and results can be received in as little as 30 minutes. Testing may be done if you are high-risk or there is concern about your symptoms.

Treating and managing your symptoms

In most cases, treatment is unnecessary in otherwise healthy people. The virus will run its course in seven to ten days, but sometimes lasts as long as 14 days. People are advised to drink extra fluids to stay well hydrated, get extra rest, and treat symptoms for comfort.

Antiviral medications may be prescribed. However, these medications are only effective if taken within the first 48 hours of symptom onset. Also, these medications only potentially shorten the timeframe of the virus, they do not cure the virus or stop the symptoms. These medicines are recommended for patients who are high-risk.

Complications of Influenza

For those who are high-risk, influenza poses a threat they may not be able to fight. The virus can make them weaker, and it can be harder for their bodies to recover. Influenza may result in:

  • Pneumonia
  • Asthma
  • Bronchitis
  • Hospitalization
  • Heart problems
  • Ear infection
  • Death

How to prevent Influenza

To prevent contracting influenza, healthcare providers strongly encourage patients to consider yearly influenza vaccinations. This is especially true for those who are high-risk. You can discuss this with your healthcare provider and determine whether this would be best for you. Vaccines are available for anyone 6 months of age and older. Vaccines have been shown to decrease symptom severity and length even in people who contract the virus.

Controlling the spread

Due to the highly contagious nature of the virus, it is important to prevent spreading it if you or anyone around you has it. Remember, even if you have not started having symptoms you still may have acquired the virus. Prevent spreading it by:

  • Frequent hand washing with warm water and soap or use sanitizer if necessary
  • Do not touch your nose, mouth, or eyes
  • Stay home - do not go out to public places when you have symptoms or have been in contact with someone who does
  • Avoid being around other people who have symptoms as much as possible
  • Clean surfaces that are frequently touched like doorknobs, phones, computers, etc.
  • Proper diet and water intake

Whilst this illness can make you feel very unwell, most otherwise healthy people are able to return to normal life within a week to ten days. Taking adequate measures to prevent the spread of influenza can also be instrumental in reducing the number of people who contract it.

References

Cleveland Clinic. Influenza (Flu)

National Geographic Society. Viruses

National Library of Medicine. Bean, B., et al. Survival of influenza viruses on environmental surfaces

A Cell Press. Influenza Virus

Medscape. Influenza

Mayo Clinic. Influenza (flu)

National Library of Medicine. Boktor, S. Influenza

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