Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. There are several types of influenza viruses, but the two main types that cause seasonal flu are influenza A and influenza B. Let’s explore some important information about these two types of influenza viruses. 1. Influenza A:
– Influenza A viruses are further classified into different subtypes based on the presence of specific proteins on their surface, namely hemagglutinin (H) and neuraminidase (N). Examples of subtypes include H1N1 and H3N2.
– Influenza A viruses are known to infect humans, birds, and some animals. They have the ability to cause pandemics, which are global outbreaks of a new flu virus that can spread rapidly and affect a large number of people.
– Influenza A viruses are more likely to undergo genetic changes (mutations) and antigenic drift, leading to the emergence of new strains. This is why seasonal flu vaccines need to be updated regularly to provide protection against the most prevalent strains. 2. Influenza B:
– Influenza B viruses are not classified into subtypes like influenza A viruses. They are known to primarily infect humans and are less likely to cause pandemics compared to influenza A viruses.
– Influenza B viruses also undergo genetic changes, but at a slower rate than influenza A viruses. This means that the strains of influenza B viruses in circulation may remain relatively stable for longer periods.
– Influenza B viruses can cause similar symptoms as influenza A viruses, including fever, cough, sore throat, body aches, fatigue, and respiratory symptoms. The severity of illness can vary from mild to severe, and it can also lead to complications, especially in vulnerable populations such as young children, older adults, and individuals with underlying health conditions. Prevention and Treatment:
– The most effective way to prevent influenza A and B is through vaccination. Annual flu vaccines are recommended for everyone aged 6 months and older, as the circulating strains may change from year to year.
– In addition to vaccination, practicing good hygiene is crucial in preventing the spread of influenza viruses. This includes frequent handwashing with soap and water, covering your mouth and nose with a tissue or your elbow when coughing or sneezing, and avoiding close contact with sick individuals.
– Antiviral medications may be prescribed by healthcare professionals to treat influenza. These medications can help to reduce the severity and duration of symptoms when taken within a specific timeframe after the onset of illness. However, they are most effective when started early in the course of the illness. It’s important to note that the flu can be a serious illness, especially for certain high-risk groups. If you experience flu-like symptoms or have concerns about influenza, it is recommended to seek medical advice from a healthcare professional. They can provide a proper diagnosis and guidance on the most appropriate treatment options.


1. Centers for Disease Control and Prevention (CDC). (2021). Types of Influenza Viruses. Retrieved from

2. World Health Organization (WHO). (2021). Influenza (Seasonal). Retrieved from

3. Centers for Disease Control and Prevention (CDC). (2021). Key Facts About Influenza (Flu). Retrieved from

4. Centers for Disease Control and Prevention (CDC). (2021). Influenza Antiviral Medications: Summary for Clinicians. Retrieved from

5. Chiu, S. S., Chan, K. H., & Chu, K. W. (2010). Influenza B Lineage-Based Vaccine Match and Vaccine Effectiveness. Journal of Infectious Diseases, 201(7), 1027–1035. doi: 10.1086/651123 Please note that the information provided is for educational purposes and should not replace professional medical advice.

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