An agent added to some vaccines that enhances the immune system’s response to vaccine antigens. Adjuvants used in vaccines include aluminum salts and, in Canada and the European Union, squalene, which [..]

A possible side effect resulting from a vaccination.

A protein generated by the immune system in response to the presence of a specific antigen. Antibodies attach to that antigen to help counter its effects.

A substance that provokes the immune system to generate antibodies against it.

A white blood cell that recognizes antigens, binds to them, ingests them, breaks them down, and then presents pieces of them to T cells.

Change in the genetic makeup of a virus, especially an influenza virus, that leads to a new strain of the virus. Antigenic drift causes the virus’s outer surface to appear different to a host previous [..]

The process by which different influenza A viruses combine to result in a new subtype of virus. Antigenic shift may result in global disease spread, or pandemic, because humans will have few or no ant [..]

Antibody that neutralizes a toxin. Diphtheria antitoxin, for example, is derived from the blood of horses immunized with diphtheria toxin and is given, along with antibiotics, to treat patients with c [..]

The process of weakening a pathogen. Attenuation may be achieved in a variety of way: by exposing the pathogen to heat or chemicals, for example, or by passing the pathogens through a growth medium ma [..]

A group of microscopic single-celled organisms. Some bacteria are capable of causing disease in humans and other organisms.