Biological plausibility
A relationship between two things or a situation in which something could occur based on how our bodies work.
Bacteria
Microscopic one-celled organisms found everywhere including on and in our bodies. While some bacteria are helpful, some cause illness. Examples of dangerous but vaccine preventable bacterial diseases include diphtheria, pertussis, tetanus, Haemophilus influenzae, and pneumococcal disease.
B cells
Small white blood cells that help the body defend itself against infection. These cells are produced in bone marrow and develop into plasma cells which produce antibodies. Also known as B lymphocytes
Attenuated vaccine
A vaccine containing a virus that is so weakened it cannot make you sick but your body can still recognize the virus and produce antibodies to fight it. Attenuated vaccines currently licensed in the United States include measles, mumps, rubella,…
Asymptomatic infection
The presence of an infection without symptoms. Also known as subclinical infection. People with asymptomatic infections can sometimes spread an illness.Â
Asthma
An ongoing medical condition where the bronchial tubes (in the lungs) become easily irritated. This causes wheezing, coughing, difficulty breathing and production of thick mucus. Why someone gets asthma is not yet known but environmental triggers, drugs, food allergies, exercise,…
Association
The terms association and relationship are often used interchangeably. When two things happen close together in time or when one thing causes another thing. See causal and temporal association.
Arthritis
A medical condition with inflammation in the joints which results in pain and difficulty moving. It may be temporary or long-lasting.
Arthralgia
Joint pain.
Antiviral
Literally “against-virus” — any medicine capable of destroying, weakening, or treating a virus.