The severity of the allergic reaction to pollen varies from person to person according to:
- the immune system of the sensitized person which reacts in different degrees to the allergen
- the type of pollen to which the person is allergic
- the intensity of the pollen season.
Pollen allergy in Belgium
According to Sciensano:
- an estimated 10% of Belgians are allergic to tree pollen from the Betulaceae family (birch, hazel, alder and hornbeam)
- an estimated 18% of Belgians are allergic to grass pollen.