April 26, 2024

How Much Do You Know About Influenza?

Every Year, Influenza Affects Millions. What if You Could Minimise Your Risk?

Influenza, commonly known as flu is a highly contagious respiratory illness caused by influenza viruses. It affects people of all ages causing mild to severe symptoms and even death in some cases. Typically, flu infections peak during the winter months. Influenza is responsible for an estimated 290,000 to 650,000 deaths every year worldwide.

There are 4 types of influenza viruses namely A, B, C, and D. Influenza A and B viruses cause seasonal flu outbreaks in humans, particularly during the winter. Influenza C virus causes illness throughout the year. Influenza D virus primarily affects cattle and pigs.

Influenza A virus has the potential to cause pandemics- widespread outbreaks that may spread across multiple countries or even continents. Pandemics occur when new strains of influenza A virus emerge against which people have little or no immunity.

Transmission of Influenza

The influenza virus spreads primarily through droplets when an infected person coughs, sneezes, or talks. These droplets can be inhaled into the lungs of people nearby, leading to infection. Additionally, touching surfaces or objects contaminated with the virus and then touching your eyes, nose, or mouth can also contribute to transmission.

Influenza is highly contagious and those who are sick may spread the virus to others even before they begin to experience any symptoms themselves. This makes it challenging to control its spread, especially in crowded settings such as schools and public transport.

Symptoms of Influenza

Source: WHO

It is important to recognise the symptoms of flu and seek early treatment to avoid severe disease or complications.

Common symptoms of influenza are:

Fever > 100°F
Dry cough
Sore throat
Runny nose
Weakness
Muscle aches
Headache
Shivering
Kids may also get vomiting or diarrhea

Following are the warning signs of a severe influenza infection:

Difficulty breathing
Face or lips turning blue
Chest pain
Dehydration (Dry mouth, Decreased frequency and amount of urine)
Fits
Fever > 104°F

Contact your healthcare provider or visit a nearby hospital if you develop any of the warning signs listed above.

Complications of influenza

Mostly, influenza causes a mild illness and goes away on its own but in some people, it may cause severe complications such as:

Severe infection of the nose, throat, and lungs
Pneumonia
Ear and sinus infections
Heart disease and brain infection in rare cases
Failure of multiple organs
Death in severe cases
Depression after recovery

Some people are at an increased risk of developing complications. These include:

Kids younger than 12 months of age
Pregnant women
Adults 65 years and older
People who live in crowded places like nursing homes, military barracks, or childcare centers
Patients admitted to hospitals
Individuals with weak immune systems
People who are obese or overweight
People with long-term heart, lung, or brain disease

What is the difference between a common cold and flu?

Source: CDC

Cause: Flu is often confused with common cold but each is caused by different types of viruses. The common cold is usually caused by rhinoviruses while the flu is caused by the influenza viruses.

Symptoms: Typically, the flu comes on more suddenly and causes more severe symptoms. The common cold develops slowly and has milder symptoms.

Fever: Fever is more common and higher in the flu as compared to the common cold.

Complications: The flu is more likely to lead to severe complications like pneumonia and even death in high-risk individuals.

Seasonal Changes in Influenza

Influenza viruses are constantly changing due to mutations. As a result, new strains of influenza viruses emerge every year making them harder to treat. If you get infected with a specific strain of influenza virus, your body develops immunity against that strain. However, this immunity does not prevent infection by other strains of influenza viruses.

Although you may get flu at any time during the year the virus spreads more easily during the winter. Cold and dry conditions are favorable for the virus to survive and spread from person to person. The peak flu season in Australia lasts from April to October every year.

Treatment of Influenza

Influenza is a self-limiting disease and most people recover without treatment. Here are some recommended treatment options to manage influenza:

Stay at home and avoid contact with others to prevent the spread of the virus
Wear a face mask while you are sick
Use heat packs or hot water bottles to relieve muscle aches
Drink plenty of water or fresh juices to stay hydrated
Use honey for sore throat and inhale hot water steam for stuffy nose
If you have severe symptoms or your symptoms are not improving, contact your healthcare provider or visit a nearby hospital

Your healthcare provider may prescribe a few medications to help ease the symptoms. These include:

Antivirals: such as Oseltamivir or Zanamivir. They reduce the severity and duration of illness and work best when taken within 2 days of the onset of the disease. They may cause a few side effects such as nausea, vomiting, diarrhea, or breathing problems in people with lung disease.
Paracetamol, ibuprofen, or aspirin for muscle aches and fever (Don’t give aspirin to kids younger than 18 years)
Anti-histamines for sneezing and runny nose
Cough Syrups

How to prevent flu?

Source CDC

Prevention is the best strategy to treat influenza. Here are some practical tips to protect yourself and others from getting the flu:

Wash your hands frequently with soap and water for at least 20 seconds, especially after coughing or sneezing
Use an alcohol-based hand sanitizer if soap and water are not available
Avoid touching your face, nose, or mouth without washing your hands
Cover your mouth and nose with tissue paper when coughing and sneezing
Regularly clean and disinfect surfaces that may be contaminated with the virus such as door knobs, table tops, electronic devices, etc
Avoid visiting crowded places during the peak flu season
Avoid close contact with people who are sick
Eat a balanced diet and exercise regularly
Take adequate sleep and manage stress by practicing stress reduction techniques such as meditation and yoga

Flu Vaccine

The best way to prevent flu is to get a flu vaccine every year. While the vaccine is not 100% effective. it significantly lowers the risk of contracting the virus. It's recommended to get vaccinated before the start of flu season to ensure optimal protection. Flu vaccines are typically composed of weakened or killed flu viruses making them safe for most individuals. Even if you get sick after getting the flu vaccine, it helps reduce the severity of the illness and prevents flu-related complications.

The Australian Immunisation Handbook recommends an annual flu vaccine for everyone 6 months and older.

In 2022, approximately 38.7% of Australians aged over 6 months received the influenza vaccine.

It is normal to experience some mild side effects after getting a flu shot. These are:

Pain, redness, and swelling at the site of injection
Headache
Fever
Nausea
Muscle pain
Fatigue
Lightheadedness
Some people may get life-threatening allergic reactions from a flu vaccine but these are very rare

Conclusion

Flu is a highly contagious illness caused by the influenza virus. It usually causes a mild infection and most people recover without treatment. However, some individuals may develop severe complications. The common symptoms of flu are high fever, muscle aches, sore throat, headache, and dry cough. The flu virus spreads through respiratory droplets when a sick person coughs, sneezes, or talks. The best way to prevent flu is to get a flu vaccine every year before the flu season starts. By practicing good personal hygiene and maintaining social distancing, we can protect ourselves and those around us from the flu.

Written for TouchBio by: Dr. Danial A.