Health Info > Fever Published on : May 3, 2024

The Difference Between Influenza A And Influenza B

Medically reviewed by Dr Nelson Lau MBBS FRACGP,
General Practitioner and Digital Health Specialist

Influenza, often referred to as the flu, is a contagious respiratory illness that affects millions of people worldwide each year. While many might use the term ‘flu’ generically, it’s essential to understand that there are different types of influenza viruses, primarily Influenza A and Influenza B. These two strains, while similar in some respects, have distinct characteristics that set them apart.

Causes

Both Influenza A and B are caused by viruses, but they belong to different families:

Influenza A

This type can be found in various animals, including ducks, chickens, pigs, and whales. It’s known for its ability to mutate rapidly, leading to the emergence of new strains almost every year. It can be transmitted from animals and birds to humans. This characteristic is why new flu vaccines are needed annually.

Influenza B

Unlike its counterpart, Influenza B is found mainly in humans. It mutates at a slower rate than Influenza A, which means fewer new strains emerge over time. Influenza B is also more common in children under 5 years old.

Differences in Symptoms

While both types of influenza can cause a range of symptoms, their intensity and duration might vary:

Influenza A Symptoms

Symptoms can be more severe and might include fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue, and in some cases, vomiting and diarrhoea. It’s worth noting that not everyone with Influenza A will experience all these symptoms.

Influenza B Symptoms

The symptoms are similar to Influenza A but are generally milder and might last for a shorter duration. However, in some individuals, especially the elderly or those with compromised immune systems, Influenza B can be just as severe.

Diagnosis

If you suspect you have the flu, it’s essential to see a healthcare provider. They’ll likely conduct a physical examination and may take a throat swab to determine the type of influenza:

Rapid Influenza Diagnostic Tests (RIDTs):

These tests can provide results in about 10-15 minutes. However, they might not catch every influenza case, especially if the viral load is low.

PCR Tests:

More accurate than RIDTs, these tests can detect the virus’s genetic material in a person through samples taken from swabs of the mouth and nose.

Treatment

Treatment for both Influenza A and B is somewhat similar:

Antiviral Medications

Drugs like oseltamivir (Tamiflu) and zanamivir (Relenza) can be prescribed to reduce the severity and duration of symptoms and may be effective in severe cases if taken within the first 2 days of symptoms. They can help to reduce the length of the illness as well as potential complications (such as pneumonia and respiratory failure).

Rest And Hydration

Regardless of the type, it’s crucial to get plenty of rest and stay hydrated. This aids the body in its fight against the virus.

Over-the-counter Medications: These can help alleviate some of the symptoms, but it’s essential to use them as directed and ensure they don’t interact with any other medications you might be taking.

Prognosis

For many, the flu, whether A or B, is an unpleasant experience but not life-threatening. However, complications can arise, especially in high-risk groups like the elderly, young children, pregnant women, and those with chronic illnesses:

Influenza A:

Given its more severe nature, it can lead to complications like pneumonia, bronchitis, sinus infections, and ear infections. In some severe cases, it can cause organ failure, sepsis, or even death.

Influenza B:

While generally milder, it can also lead to complications, especially in high-risk groups.

Other Aspects to Consider

Vaccination

Annual flu vaccines are the best protection against both Influenza A and B. Because the strains change, especially for Influenza A, it’s recommended to get vaccinated every year.

Prevention

Regular hand washing, avoiding close contact with sick individuals, and practicing good hygiene can help reduce the spread of both types of influenza.

Understanding the differences between Influenza A and B is crucial for effective treatment and prevention. While they share many similarities, recognising their distinct characteristics can aid in better management and recovery. Always consult with a healthcare provider if you suspect you have the flu, and consider annual vaccinations as a preventive measure.