The flu caused by influenza A is generally considered worse than influenza B. Influenza A often produces more severe symptoms such as stronger fevers, body aches, and more intense upper respiratory symptoms like a dry cough and sore throat. It tends to escalate quickly and can cause more complications, especially in older adults, pregnant people, and those with weakened immune systems. Influenza B symptoms tend to be milder overall but can be more severe in young children and sometimes includes more gastrointestinal symptoms like nausea and vomiting. Both flu types can cause serious illness, but influenza A is more commonly linked to severe outbreaks and pandemics, whereas influenza B tends to cause seasonal epidemics with less severity in the general adult population.
Summary of Differences:
- Severity: Flu A is usually more severe in adults; Flu B can be more severe in young children.
- Symptoms: Flu A often causes stronger fever, body aches, and respiratory symptoms; Flu B may cause more nasal congestion and GI symptoms.
- Population: Flu A affects a broader range including animals, Flu B only infects humans.
- Pandemics: Flu A can cause pandemics, Flu B cannot.
- Timing: Flu A tends to peak earlier in the flu season; Flu B usually peaks later.
Both types are included in the annual flu vaccine for protection.