Influenza A is generally considered worse than Influenza B in terms of severity and prevalence. Influenza A usually causes more cases of the flu and more severe illness, such as stronger fevers, more intense body aches, and more severe respiratory symptoms. It is also more likely to cause complications like pneumonia and bronchitis, especially in older adults, pregnant people, and immunocompromised individuals. Additionally, Influenza A has the ability to infect various species (birds, mammals) and can undergo antigenic shift, leading to pandemics. Influenza B tends to have milder symptoms overall, although it can still cause severe illness, particularly in young children. It is primarily a human-only virus and does not cause pandemics. Studies show that the clinical outcomes such as hospitalization and mortality rates can be similar between influenza A and B, especially among hospitalized patients, but flu A often leads to more intense symptoms and more cases overall. Summary table:
Aspect| Influenza A| Influenza B
---|---|---
Severity| Generally more severe| Generally milder but can be severe in
children
Commonness| More common (about 75-96% cases)| Less common (about 4-25% cases)
Infection Hosts| Humans, birds, mammals| Humans only
Pandemic Potential| Yes (due to antigenic shift)| No
Symptoms| Stronger fever, more body aches, severe respiratory symptoms| Milder
fever, less intense body aches, more GI symptoms in children
Complications| More pneumonia, bronchitis, ear infections (in children)| More
seizures, vomiting, diarrhea (in children)
Hospitalization & Mortality| Similar rates compared to B in hospitalized
patients| Similar rates compared to A in hospitalized patients
In summary, Influenza A is considered worse mainly due to its higher prevalence, pandemic potential, and generally more severe symptoms in adults, but Influenza B can still cause serious illness, especially in children.
