Influenza B During Flu Season: Symptoms and Treatment

During flu season, influenza viruses pose a significant health threat to many people. While influenza A is well-known, influenza B should not be overlooked. Influenza B is an acute respiratory infection caused by the influenza B virus, which is highly contagious and responsible for over 23% of flu cases globally. It often peaks during winter and spring. This article provides an overview of influenza B symptoms, treatment options, and prevention methods to help you stay protected.

What Is Influenza B?

Influenza B is a contagious illness caused by the influenza B virus. Unlike influenza A, which can infect humans and animals, influenza B primarily affects humans and has lower mutation rates, meaning it spreads more slowly. However, influenza B can still cause severe respiratory symptoms, particularly in vulnerable groups such as older adults, young children, pregnant individuals, those with chronic conditions and patients on immunosuppressants.

Symptoms of Influenza B

The symptoms of influenza B are more pronounced and longer-lasting than those of the common cold. Common symptoms include:

Fever
- High fever (above 38°C) often accompanied by chills or shivering.
Sore Throat and Cough
- Persistent throat pain often accompanied by a dry cough that may last for several days.
Fatigue and Muscle Aches
- Extreme tiredness, along with muscle or joint pain, is common.
Headache
- Headaches frequently occur alongside other flu symptoms.
Runny or Stuffy Nose
- Although influenza primarily affects the respiratory system, cold-like nasal symptoms may also be present.
Gastrointestinal Discomfort
- Some patients, particularly children, may experience nausea, vomiting, or diarrhoea.
Other Symptoms
- Sore eyes, swollen throat, or loss of appetite may also occur.

The incubation period for influenza B is usually 1 to 4 days, and symptoms may last for 5 to 7 days. However, fatigue can linger for a longer period. Seek medical attention if severe symptoms occur, such as difficulty breathing or a persistent high fever.

How Influenza B Spreads

The influenza B virus is transmitted primarily through two routes: 

Droplet Transmission 

The virus is released into the air when an infected person coughs, sneezes, or talks. Others can become infected by inhaling these droplets.

Contact Transmission 

Touching contaminated surfaces (such as doorknobs or mobile phones) and then touching the mouth, nose, or eyes can lead to infection.

Treatment for Influenza B

The primary goals of treatment are to alleviate symptoms and shorten the duration of illness. Common treatments include:

1. Antiviral Medications

Antiviral drugs prescribed by a doctor can effectively inhibit the virus and reduce the risk of complications. Common options include:

Oseltamivir (Tamiflu^®)

Zanamivir (Relenza^®)

Peramivir (Rapivab^®)

Baloxavir Marboxil (Xofluza^®)

Antiviral medications are most effective when taken within 48 hours of symptom onset, so early medical consultation is essential.

2. Symptom Relief

Fever Reducers: Paracetamol (Acetaminophen) or ibuprofen can help lower fever and relieve pain.

Cough Medicine: Cough syrups or lozenges can ease throat discomfort caused by a dry cough.

Hydration: Drinking plenty of water or electrolyte drinks can prevent dehydration caused by fever, sweating, or gastrointestinal symptoms.

3. Rest and Nutrition

Adequate rest and a balanced diet can boost the immune system and aid recovery.

Complications of Influenza B

If untreated, influenza B can lead to serious complications, particularly in high-risk groups. Common complications include:

Pneumonia: Viral or bacterial pneumonia is a leading complication of the flu.
Bronchitis: Influenza can worsen into chronic bronchitis, causing further respiratory issues.
Myocarditis: In some cases, the flu virus can inflame the heart muscle, leading to myocarditis.
Otitis Media: In children, influenza B can cause middle ear infections.

Seek immediate medical attention if symptoms such as chest pain, difficulty breathing, or a persistent high fever occur.

How to Prevent Influenza B

Preventing influenza B requires boosting immunity and minimising exposure to the virus. Key prevention strategies include:

1. Get Vaccinated

Annual flu vaccination is the most effective way to prevent influenza B. Vaccines reduce the risk of infection and severe complications.

2. Practice Good Hygiene

Frequent Handwashing: Wash hands thoroughly with soap or use alcohol-based hand sanitisers.
Wear a Mask: During flu season or in crowded places, wearing a mask can reduce virus transmission.

3. Boost Immunity

Maintain a balanced diet, exercise regularly, and get enough sleep to strengthen your immune system.

4. Avoid Close Contact with Sick Individuals

Limit exposure to infected individuals and isolate household members with flu symptoms to prevent further spread.

Conclusion

Influenza B is a highly contagious illness, but with proper knowledge of its symptoms, treatment options, and prevention methods, you can minimise its impact. The best way to protect yourself is by getting vaccinated annually and maintaining good hygiene. If you experience flu symptoms, seek medical advice promptly and follow your doctor’s treatment plan. For more information on influenza or to book a consultation, contact one of our family doctors today.

References

Healthline, (2024) Influenza B Symptoms: Respiratory, Body, Stomach. Retrieved January 13, 2025, from https://www.healthline.com/health/influenza-b-symptoms#treatment
Health.com, (2024) Influenza (Flu) B 2024: Symptoms, Treatment, and More. Retrieved January 13, 2025, from https://www.health.com/condition/flu/what-is-influenza-b