FLU (INFLUENZA)

About Flu (Influenza)

Flu, or Influenza is the most common and contagious viral infection in the winters. Also called Seasonal Flu for the same reason, Influenza is caused by the Influenza virus that affects your respiratory system (i.e. your lungs, throat, nose, airways, voice box, and mouth). Influenza virus can be of 4 types: Influenza A, Influenza B, Influenza C and Influenza D. Flu A, Flu B, and Flu C are common in humans while Flu D affects only cattle. Because of the commonalities between their symptoms, it is very natural to get confused between Influenza virus, Swine Flu, Rhinovirus, Allergies, RSV (Respiratory Syncytial Virus) Common cold, Pneumonia, Stomach Flu, and Covid-19. 

Influenza A, the most common Flu of all, if left uncontained has the potential to spread rapidly as it mutates faster and can grow into a massive pandemic. Influenza A can be life-threatening in some high-risk categories of patients. H1N1 virus or Swine Flu is a subtype of Influenza Type A virus. Generally, Influenza A is found to be more severe in adults, while Influenza B can become more serious in children of less than 5 years of age. Influenza B is less common when compared to Influenza A. Flu A accounts for almost 75% and Flu B is only 25% of the total Influenza cases. Flu B is also observed to be more common and more severe than Flu C. 

Influenza A virus can spread from even animals and birds to humans while Influenza B virus transmits from individual to individual and isn’t found in animals. Usually a healthy person doesn’t get affected by both Flu types simultaneously. Influenza A virus can be further categorized into several subtypes based on the proteins on its viral surface. A total of 18 Hemagglutinin (H) subtypes and 11 Neuraminidase (N) subtypes are known to experts. Influenza B virus is not classified into subtypes like Type A Flu virus. Instead, experts divide Influenza B virus into viral lineages: Victoria and Yamagata namely. 

Symptoms Of Flu

Influenza B symptoms are generally milder than Influenza A symptoms. Many symptoms of Type A Flu virus and Type B Flu virus are identical and self-diagnosable. 

They can be further classified into - 

• body symptoms which include high fever, headaches, body pain, fatigue, muscle ache, chills, 
• digestive symptoms i.e. nausea, loss of appetite, diarrhea, stomach pain, vomiting, and, 
• respiratory symptoms like sneezing, cough, sore throat, congestion, runny and stuffy nose. 

Flu symptoms in children include sudden fever (above 100.4°F or 38°C), drowsiness and lesser activity than regular days, tiredness, body pain, headache, sore throat, runny nose, dry cough, stomach ache and vomiting / diarrhea in certain cases. 

Flu Causes

An infected person, a day before the symptoms reveal and during the first 3-4 days after exposure to the Flu virus, can transmit the Influenza infection to healthy persons, from up to a 6-feet distance, according to a study. So, what causes Influenza? How does it spread? Who is at risk of getting the Influenza infection? Both Influenza A and Influenza B can spread from the infected person through contaminated droplets of their cough or sneeze, inhaled by others who come in contact with the infected person. Although less common, Influenza illness can also be transmitted when a healthy person touches their eyes, nose or mouth after touching a contaminated object / surface containing such droplets. In healthy individuals, Flu A and Flu B are most likely to cause just mild to moderate symptoms, which get resolved on their own in a week or two, without any treatment, health practitioner’s supervision or medication, unless the individual falls under high-risk category. 

Then what are the factors that put an individual at a higher risk? 

• Pregnancy
• Infants and young children (<5 years) 
• Elderly people 
• People with weakened immunity
• Patients with chronic illnesses like lung disorders, heart diseases, kidney problems, liver ailments, and other diseases like cancer, asthma, blood conditions, stroke, diabetes etc.
• Adults and kids who haven’t had their Flu vaccination yet
• People with frequent exposure to infected persons like nurses and doctors in care facilities

In such patients, the symptoms of Flu A and Flu B can get serious leading to further health complications like bronchitis, brain infection, ear infection, sinusitis, asthma attacks, pneumonia, kidney failure, myocarditis, respiratory failure, miscarriage, meningitis, myositis, and sepsis, needing immediate hospitalization.

Diagnosis Of Flu

Being diagnosed with Flu A virus doesn’t reduce or increase your chances of contracting Flu B virus. 

How is Flu diagnosed?

• Physical examination by doctor
• Understanding patient's health history and current condition
• Assessing patient’s Influenza symptoms 
• Running medical tests to confirm the diagnosis: chest X-ray, rapid antigen, rapid molecular assay, PCR etc.

Flu: Treatment & Prevention

Influenza A generally occurs in the months of January and February, while February and March are when Influenza B is quite common. Both types of Influenza are characterized by different levels of severities in different categories of patients. Flu has no cure as such. Just like the similarities in the symptoms of Influenza A and B, there is no distinct difference in their treatments too. The treatments can only provide relief to the patients from the symptoms or lower their severity, as the body usually fights off Influenza without any medications. Here’s how: 

1. Good rest, ample sleep
2. Adequate liquid intake to prevent dehydration
3. Antiviral flu medication (to be taken within 48 hours of seeing symptoms - if advised by doctor - for effective results)
4. Steam inhalation to clear nasal block 
5. Heat packs for muscle pain
6. Over-the-counter medicines (as prescribed by doctor) for other milder symptoms
7. Personal hygiene, cleanliness and self-isolation to avoid spreading infection 

When to see the doctor while fighting Flu infection?

Call for medical help immediately if there is -

• persistent pain in chest 
• difficulty in breathing
• seizures
• no improvement in Influenza symptoms
• complications in other health conditions
• rapid heart rate
• low blood pressure
• lack of urination

In case of children’s Flu, parents can even opt for home healthcare services to get assistance at their doorstep in the nick of time, which helps in detecting Flu symptoms early for their toddlers, addressing milder cases with common cold remedies, availing nutritional, dietary and immunity building tips from experts, attending to emergency symptoms and running lab tests at home.

Taking the Flu shot every Flu season without fail and encouraging others to also go for Flu vaccines are the easiest ways to prevent Flu in the first place. Flu vaccination can be given to individuals aged 6 months and above; annually once for those 9 years of age and above, and annually twice for children aged 8 and below. Flu vaccines are developed in such a way that they can protect the recipients from the different strains of the Influenza virus. Based on the understanding of which types of Flu viruses would be circulating during the Flu season, a trivalent vaccine has been devised to protect the individual against H1N1 Type A, H3N2 Type A and Type B Influenza virus whereas a quadrivalent vaccine is meant for all of the above three and another Influenza B virus additionally. 

Apart from the Flu shot, one can also follow some basic hygiene practices to prevent the spread of the infection which includes -

• Washing hands thoroughly with water and soap and using an alcohol-based hand sanitizer regularly after touching surfaces
• Covering mouth with a tissue or sneezing and coughing into one’s elbow to avoid infected droplets from spreading in the air 
• Keeping children indoors and self-isolating once Flu-like symptoms set in
• Not sharing belongings and avoiding contact with infected people till they recover fully
• Using a mask in crowded areas 
• Keeping surroundings clean and disinfected always
• Reaching out to the doctor in case of prolonged period of sickness 

Disclaimer: 

This page is for informational purposes only and not a replacement to any direct medical consultation provided by professionals. Should you have any questions about your health, reach out to qualified healthcare providers and medical experts for personalized advice and further guidance.