What is the Difference Between Influenza A and B?

The main differences between Influenza A and B are their severity, transmission, and host range. Here are the key differences:

1. Severity: In general, Influenza A is more severe in adults, while Influenza B is more common in children and tends to be milder to moderate in healthy children. However, Influenza B can be more severe in children under the age of 5. Some Influenza A subtypes, such as H3N2, have been associated with more hospitalizations in the past.
2. Transmission: Both Influenza A and B are highly contagious and cause the same type of illness and symptoms. They spread through respiratory droplets, which can be transmitted when an infected person coughs, sneezes, or talks.
3. Host Range: Influenza A viruses have a broader host range, infecting humans, birds, and sometimes pigs. Wild aquatic birds are often the hosts for a variety of Influenza A viruses, which can sometimes be transmitted from bird to human, causing devastating outbreaks. Influenza B viruses almost exclusively infect humans and are less common than Influenza A.
4. Mutation Rate: Influenza B viruses mutate about two to three times more slowly than Influenza A viruses.
5. Subtypes and Lineages: Influenza A viruses are further classified into subtypes, while Influenza B viruses are classified into two lineages: B/Yamagata and B/Victoria. Influenza A subtypes can be further broken down into different genetic "clades" and strains.

Both Influenza A and B can cause seasonal epidemics of respiratory illness, and yearly vaccination can help prevent contracting either type.

Comparative Table: Influenza A vs B

Influenza A and B are two main types of flu viruses that cause seasonal flu epidemics. Although both types can cause mild to severe symptoms, there are some differences between them:

While both Influenza A and B can cause serious and life-threatening diseases, Influenza A is generally considered more severe than Influenza B. However, the signs and symptoms of both types are similar, and both infections can be passed from person to person.