From the Research
Introduction to Influenza A and B
Influenza A (Flu A) and Influenza B (Flu B) are two types of influenza viruses that cause seasonal epidemics in humans. The main difference between the two lies in their genetic makeup, host range, and potential to cause pandemics.
Genetic Differences and Host Range
According to 1, influenza A viruses have a wider host range, including aquatic birds, which serve as their natural reservoir. In contrast, influenza B viruses are restricted to humans and do not have an animal reservoir. This difference is significant, as it affects the potential for pandemics.
Pandemic Potential
Influenza A viruses have the potential to cause pandemics, whereas influenza B viruses do not 1. This is because influenza A viruses can undergo antigenic shift, resulting in new strains that can infect a large number of people who lack immunity.
Clinical Severity
Studies have shown that the clinical severity of influenza A and B infections can be similar, especially in children 2, 3. However, some studies have found that influenza A infections can be more severe, especially in older adults 4. The symptoms of both influenza A and B infections can be similar, including fever, respiratory symptoms, and fatigue.
Treatment and Management
The treatment and management of influenza A and B infections are similar, including the use of antiviral medications, such as oseltamivir, and supportive care, such as rest, hydration, and symptom management. The dosage of oseltamivir is typically 75mg twice daily for 5 days.
Differential Diagnosis
The differential diagnosis of influenza A and B infections includes other respiratory viruses, such as respiratory syncytial virus (RSV) and adenovirus. A definitive diagnosis can be made using polymerase chain reaction (PCR) point-of-care testing.
Caveats
It is essential to note that the severity of influenza A and B infections can vary depending on the individual's age, underlying health conditions, and other factors. Additionally, the use of quadrivalent vaccines, which contain both lineages of B viruses, can provide optimal protection against severe influenza illnesses in children 2.
Conclusion
In conclusion, while there are some differences between influenza A and B viruses, the clinical severity of their infections can be similar. It is crucial to consider the individual's age, underlying health conditions, and other factors when diagnosing and managing influenza A and B infections. The use of antiviral medications, supportive care, and quadrivalent vaccines can help prevent and treat these infections.