Useful words

Acute – a short sharp illness that may be severe but from which most people will recover in a few weeks without lasting effects.

Antibody – a type of immunoglobulin (protein) produced by your body’s immune system as part of a defence reaction against an invading substance (antigen).

Antigen – an invading substance that may be part of a virus. Your body’s immune system will defend against the antigen by producing antibodies.

Autoimmune disease – a type of disease where the immune system mistakenly attacks another part of the body.

Chronic – an illness that lasts a long time (more than six months), possibly for the rest of your life.

Co-infection – being infected with more than one virus at the same time.

Inflammation – the first response of your immune system to infection, commonly indicated by heat, swelling, pain and tenderness.

Vaccination – injection with a vaccine. A vaccine is a substance containing an inactivated (very
weakened or dead) form of the virus that cannot cause disease. It is introduced into your body to
cause an immune reaction to protect you against getting the virus.