Flu: Reasons, Symptoms, Complications and Management

Research Based
Medically reviewed by - Dr. Abdul Khalique, MD Written by - Dr. Diksha Sangle
  • Flu
  • 16 Aug 2023


What is flu ?

Influenza, sometimes known as the flu, is a viral infection that affects the respiratory system, including the nose, throat, and lungs. The flu is extremely contagious because it spreads quickly through droplets when an infected person coughs, sneezes, or talks.1Overview| Researched based study from

Influenza, sometimes known as the flu, is a viral infection that affects the respiratory system, including the nose, throat, and lungs.


How widespread is the flu?

Millions of people experience the common viral infection known as influenza each year. The World Health Organization (WHO) estimates that seasonal flu causes between 3 and 5 million illnesses each year and 290,000 to 650,000 fatalities.1Prevalence| Researched based study from

However, as not all cases are reported or diagnosed, the actual number is probably substantially greater.

  • The US Centers for Disease Control and Prevention (CDC) estimates that between 9 million and 45 million persons contract the flu each year.1Prevalence| Researched based study from
  • In temperate climates, the flu is most prevalent in the winter, but it can happen all year round in tropical areas.
  • Several variables, such as the viral strain, vaccination rates, and how well the vaccine matches the circulating virus, can affect the number of flu cases and deaths yearly.1Prevalence| Researched based study from

Flu & Cold

How do the flu and the common cold differ from one another?

  • They are both viral respiratory infections, but the viruses that cause them to differ. Therefore, their symptoms and severity vary.
  • The influenza virus causes the flu, but numerous distinct types of viruses, including rhinoviruses, coronaviruses, and adenoviruses, cause the common cold.


Symptoms of flu

  • Fever
  • Chills
  • Cough
  • Sore throat
  • Runny or congested nose
  • Body or muscle aches
  • Headaches
  • Frustration (weariness)
  • Diarrhea and vomiting (more in children)

These symptoms might be moderate or severe, and they can appear unexpectedly. Keep in mind that not everyone who has the flu will experience all of these symptoms; in fact, some people may only have a few. Some individuals could also not develop a fever.2Symptoms| Researched based study from


What causes flu?

  • Each type of influenza virus, including influenza A, B, and C, can evolve and produce various strains.
  • They are very contagious and spread from one person to another whenever an infected individual speaks, sneezes, coughs, or releases droplets while doing so.
  • These can then settle on surfaces where they can be picked up by people who then contact those surfaces and touch their nose, mouth, or eyes, or they can fall on surfaces where they can be inhaled by others who are close.4Causes| Researched based study from
  • Additionally, the virus can spread when you touch your face after touching a surface or object that has the infection.
  • In some cases, individuals may have an infection without displaying symptoms, but they can still spread the virus to others.4Causes| Researched based study from


Risk factors

There are a few factors taken into consideration.


  • Complications are more likely to occur in young children, older people, and those with compromised immune systems.

Chronic medical conditions

  • People with chronic conditions like diabetes, heart disease, asthma, or HIV/AIDS are more susceptible.


  • Because pregnant women’s immune systems are compromised, they are more vulnerable.3Risk| Researched based study from

Living or working conditions

  • People are more likely to be exposed if they live or work in crowded places like elderly homes, schools, or nursery facilities.3Risk| Researched based study from

Weakened immunity

  • People with compromised immune systems, including chemotherapy patients and organ transplant recipients, are more vulnerable.


  • It has a higher risk attached to it.


  • Smoking weakens the immune system, making it more challenging for the body to fight off diseases like the flu.3Risk| Researched based study from


How is flu diagnosed?

Physical examination

In order to rule out other diseases that can have symptoms that are similar to the flu, doctors perform a thorough examination. This decision is often made based on

  • Person’s symptoms
  • Medical history
  • Travel history
  • Physical examination.

Laboratory tests

  • Rapid influenza diagnostic test (RIDT), which includes swabbing the inside of the nose or throat to acquire a sample of respiratory secretions, is the most popular test to identify the flu.6
  • After that, the sample is examined for the presence of virus antigens.
  • It’s important to remember that these tests don’t always work as expected and can sometimes give false-negative findings, which means that even if a person may have the flu, the test may not pick it up.

Based on the symptoms and risk factors, your doctor may order additional tests or prescribe antiviral medicine if you have the flu, but the quick test is negative.6Diagnosis| Researched based study from


FLU and how is it managed?

How is it managed?


  • Acetaminophen or ibuprofen, two over-the-counter medications, can lower fever and ease bodily aches. It is also possible to utilize cough suppressants and nasal decongestants.5Management| Researched based study from

Antibiotics for viruses

  • In particular, for those at high risk, a healthcare provider may prescribe them to lessen the intensity and length of the sickness.


  • Rest is crucial to preserving energy and assisting the body in battling the infection.


  • Water, juice, and broth are all good sources of fluids that can assist in preventing dehydration and loosening mucus.

Stay at home

  • When suffering with the flu, it’s essential to stay at home and refrain from close contact with people.2Management| Researched based study from

Use a humidifier

  • A humidifier can facilitate better breathing and relieve congestion.2Management| Researched based study from

Salt water to gargle

  • Salted water gargling might ease sore throat pain.

Eat nutritious foods.

  • An immune system supported by a nutritious diet rich in fruits and vegetables.

Keep warm

  • Wearing cozy, comfortable clothing can reduce body pains and chills.2Management| Researched based study from


What is the duration of the flu?

  • In most cases, the flu lasts 7–10 days, while it can occasionally last longer in elderly individuals, children, and those with compromised immune systems.
  • After the severe symptoms have subsided, it’s not unusual for people to feel weak or exhausted for several days or weeks.
  • It’s essential to call a doctor if symptoms last longer than ten days or if any new symptoms appear to rule out problems or secondary infections.


Complications related to flu


  • Following the flu, the lungs may become infected with this potentially dangerous bacterial infection. Chest pain, fever, coughing, and breathing difficulties are possible side effects.3Complications| Researched based study from

Ear and sinus infections

  • It can occasionally result in secondary infections that cause discomfort, pressure, and drainage in the sinuses and ears.3Complications| Researched based study from


  • Dehydration may result from the vomiting and diarrhea that the virus can bring on. Children and older individuals are two groups who may be particularly at risk.

Chronic illnesses get worse

  • People with chronic medical conditions may experience worsening symptoms from the flu.

Heart, brain, or muscular tissue inflammation

  • Rarely, the flu can result in tissue inflammation in the heart, brain, or muscles, which can be fatal.3Complications | Researched based study from


Preventive factors

Get a vaccine

  • The best method of prevention is the flu shot. It should be used by everyone above the age of six months.7Prevention | Researched based study from

Regular hand washing

  • Regular soap, and water hand washing. Additionally, efficient are hand sanitizers.7Prevention | Researched based study from

Avoid being close to sick people

  • This makes contracting an infection more likely

Cover your mouth and nose

  • Avoid touching your face. This aids in stopping the transmission of viruses.

Keep up an active lifestyle

  • Your risk can be decreased, and your immune system can be kept robust with a good diet, regular exercise, and enough sleep.

Keep everything tidy

  • It’s crucial to clean and disinfect commonly touched items like doorknobs, keyboards, and phones since flu viruses can survive on them for several hours.7Prevention | Researched based study from


What is the prognosis ?

  • The prognosis for flu varies according to the person and their general health. Most of the time, there are no issues during the week- or two-long recovery process.
  • If they obtain timely medical care and look after themselves, the majority of patients have a good prognosis.
  • To protect yourself and others, treating the flu seriously and taking precautions to stop its spread is crucial.5Prognosis | Researched based study from
Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

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