Influenza virus can be distinguished into influenza virus A, B and C on the basis of antigenic differences between their nucleoprotein and matrix proteins. Type A influenza viruses are typically more prevalent than type B viruses and are associated with most serious influenza epidemics, while type B influenza infections are usually milder.
Who is most at risk?
- Pregnant women at any stage of pregnancy
- Children younger than 5 years
- People older than 65 years
- People with chronic medical conditions such as HIV/Aids, asthma, heart and lung disease and diabetes.
- People with increased risk of influenza, which include health care workers.