Influenza: Symptoms, Causes, and Treatments

Written by Medicover Team and Medically Reviewed by Dr Vasantha Kumar , General Medicine

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Influenza (flu) is a contagious viral respiratory disease caused due to the influenza virus. Its symptoms are Fever, Headache, vomiting, body pains, etc.

It spreads through respiratory droplets when infected individuals

• Talk
• Cough
• Sneeze

The flu season typically runs from April to September, with varying severity and duration. High-risk groups include young children, the elderly, pregnant women, and those with weakened immune systems.

What are the Influenza Symptoms and Warning Signs?

The flu Influenza symptoms include

• Headache
• Vomiting and diarrhea are common in some individuals
• Cough
• Muscle or body aches
• Fever or feeling feverish/chills
• Fatigue (tiredness)
• Runny or stuffy nose
• Sore throat

Warning Signs That Require Immediate Medical Attention

In Adults:

• Difficulty breathing or shortness of breath
• Chest pain or pressure
• Sudden dizziness or confusion
• Severe or persistent vomiting
• Symptoms that improve but then return with fever and worse cough

In Children:

• Fast or troubled breathing
• Bluish lips or face
• Chest pain
• Severe muscle pain
• Not waking up or interacting
• Seizures
• Dehydration (no tears when crying, significantly fewer wet diapers)
• Symptoms that improve but return worse

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What Are the Different Types of Influenza?

Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. There are four main types of influenza viruses:

Influenza A

• Primary cause of seasonal flu epidemics and pandemics.
• Infects humans, birds, pigs, and other animals.
• Subtyped based on two surface proteins: Hemagglutinin (H) and Neuraminidase (N) , e.g., H1N1, H3N2.
• Known for mutating rapidly, which leads to new strains and requires yearly vaccine updates.
• Can cause severe illness and has been responsible for global pandemics.

Influenza B

• Affects only humans and seals.
• Also contributes to seasonal flu outbreaks, but generally causes less severe epidemics than Type A.
• Not subtyped like Type A but divided into two main lineages: B/Yamagata and B/Victoria.
• Included in seasonal flu vaccines.

Influenza C

• Infects humans and pigs.
• Causes mild respiratory illness and does not cause epidemics.
• Rarely included in routine flu surveillance or vaccination programs due to its mild nature.

Influenza D

• Primarily affects cattle and does not infect humans at this time.
• Of interest mainly in veterinary and agricultural contexts.

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What Are the Common Causes and Risk Factors of Influenza?

The flu is caused by influenza viruses that infect the nose, throat, and lungs. When sick people cough,sneeze or talk, respiratory particles are released into the air and may infect the surrounding individuals. A person can also catch the flu by touching the lips, eyes, or nose with contaminated hands. Some of the causes of influenza are:

• Influenza viruses (types A, B, and C) are the primary cause.
• Person-to-person transmission through coughing, sneezing, or talking.
• Touching contaminated surfaces and then touching the face, eyes, or mouth.
• Close contact with infected individuals, especially in crowded settings.
• Seasonal changes, particularly in colder months, increase the likelihood of outbreaks.
• Weakened immune system, making it easier for the virus to infect.
• Underlying health conditions, such as asthma or heart disease, can increase susceptibility.

Risk Factors of Flu (Influenza)

The influenza risk factors are:

• Age: Seasonal influenza targets young children from six months to 5 years old and adults 65 years old or older.
• Weak immune system: The immune system is affected by HIV/AIDS, poor nutrition, smoking, alcoholism, chronic steroid use, organ transplants, cancer, etc. This may raise the chance of contracting the flu and make complications more likely.
• Chronic illnesses: Chronic ailments may increase the severity of influenza and lead to complications, including lung diseases,diabetes,heart disease, metabolic abnormalities, etc.
• Pregnancy: Pregnant women are more susceptible to influenza during the second and third trimesters.Also, women are more prone to experience influenza-related issues two to four weeks after giving birth.

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How Influenza is Diagnosed?

• Medical professionals will first assess the medical history and learn more about the symptoms to diagnose flu.
• There are various flu tests available.
• One of them is polymerase chain reaction (PCR) testing which is more sensitive compared to other tests and may be able to determine the influenza strain.

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What Are the Treatment Options for Influenza (Flu)?

Many people can take care of the flu illness themselves. Painkillers can manage headaches or body aches. You need to rest more and drink plenty of fluids to recover from the infection.

In case of a severe disease or a higher risk of complications, the doctor may prescribe antiviral drugs to treat the flu. These were some Influenza treatments.

Treatment Options:

Medications

• Over-the-counter medications: Pain relievers such as paracetamol or ibuprofen help reduce fever, headaches, and body aches. Decongestants and cough suppressants can ease respiratory symptoms.
• Antiviral drugs: In more severe cases or for high-risk patients (such as the elderly, pregnant women, or those with chronic conditions), doctors may prescribe antiviral medications like oseltamivir (Tamiflu) or zanamivir. These drugs can shorten the duration of symptoms and help prevent complications if taken within the first 48 hours of symptom onset.

Supportive Therapies

• Rest and hydration: Ample rest and increased fluid intake are essential to help the body fight off the infection.
• Nutritional support: Eating light, nutritious meals and maintaining electrolyte balance can support faster recovery.
• Oxygen therapy: In rare severe cases, particularly where respiratory distress occurs, oxygen support may be needed in a hospital setting.

Recovery Timeline

• Most people recover from the flu in 5 to 7 days, although fatigue and a mild cough may linger for up to two weeks. High-risk individuals may experience a longer recovery period, especially if complications such as pneumonia arise.

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When to see a doctor?

Most people with influenza can manage it at home and rarely require medical attention. Call your doctor if you are experiencing flu-like symptoms and feel you could get sick.

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What Is the Recovery Process After Influenza Treatment?

Recovery from influenza doesn't end when the fever breaks. While most individuals start feeling better within a week, full recovery including regaining energy and respiratory strength may take longer.

Post-Treatment Expectations and Follow-up

• Follow-up appointments: For most patients, follow-up is not mandatory unless symptoms persist beyond 10 days or worsen. However, high-risk individuals (elderly, immunocompromised, or those with chronic conditions) may be advised to schedule a follow-up visit within 1 - 2 weeks after initial treatment.
• Watch for warning signs: Difficulty breathing, chest pain, or high fever returning could indicate complications like pneumonia and require prompt medical attention.

Lifestyle and Diet Recommendations

• Rest and gradual activity: Light activities can be resumed once the fever subsides, but full physical exertion should be avoided for at least 1 - 2 weeks to prevent relapse.
• Hydration and nutrition: Continue to drink plenty of fluids and consume a diet rich in vitamin C, zinc, and protein to support immune function.
• Avoid smoking and alcohol: These can irritate the respiratory system and slow down the healing process.
• Sleep well: Adequate sleep is critical for immune restoration and energy recovery.

Long-Term Outlook

For healthy individuals, long-term effects are rare. Mild fatigue and a lingering cough can last up to 2 - 3 weeks, but typically resolve without intervention.

Medicover's Support Services:

Medicover is committed to your complete recovery journey. Our post-treatment care includes:

• Access to teleconsultations for ongoing concerns.
• Dietary counselling to help rebuild strength and immunity.
• Specialist referrals if respiratory therapy or additional diagnostics are needed.
• Vaccination guidance to prevent future infections, especially before flu season.

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What Precautions Can Help Prevent Influenza?

Prevention of Flu (Influenza)

• Get the annual flu vaccination, as it can reduce the severity of the infection and avoid hospitalisation.
• There are many Influenza vaccine options, including nasal spray and conventional jabs. The doctor could suggest a specific type of immunization depending on the health and risk factors.

Other prevention methods are

• Follow healthy habits, such as washing your hands with soap and water.
• Use a disinfectant to clean surfaces and items like furniture and toys.
• Covering your mouth while coughing and sneezing will help reduce the risk of infection.
• Avoiding touching mouth, nose, or eyes with unwashed hands.
• Sleep for eight hours every night.
• Regular exercise helps boost the immune system.

Complications of Flu (Influenza)

The flu complications are as follows:

• Pneumonia
• Bronchitis
• Asthma attacks
• Heart problems
• Infected ears
• Acute respiratory distress syndrome

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Do's and Dont's

Follow the below-given do's and don'ts for influenza to prevent the disease and its severity.

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Our Experience Treating Flu (Influenza)

At Medicover Hospitals, we have the most trusted group of doctors and healthcare professionals skilled at providing the best medical treatment to patients while showing compassion and care.

Our diagnostic department is equipped with the latest technology and equipment to conduct the necessary investigations for diagnosing Influenza. Our excellent doctors follow a multi-disciplinary approach to identifying and treating the condition.

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