Types of Vaccine
Vaccines can be divided in to two main types:
Find further information on inactivated viruses by reading each of the headings below...
These vaccines contain whole killed bacteria or viruses, currently there are no ‘whole killed’ bacteria vaccines used in the UK. Examples of ‘whole killed’ vaccines in other countries include influenza, hepatitis A and polio vaccines.
Most vaccines in the UK NHS schedule are subunit vaccines. They don’t contain whole bacteria or viruses. They contain only polysaccharides (sugars) or proteins from the surface of the pathogens, and are recognised as antigens by the immune system. The different types of subunit vaccines include:
Toxoid vaccines - some bacteria release toxins when they infect the body. The immune system recognises these as foreign antigens. Vaccines can be made from the inactivated toxins (which are more harmful), rather than a vaccine against the bacteria, to trigger a stronger immune response. Examples include diphtheria, tetanus and pertussis (whooping cough).
Conjugate vaccines - In most conjugated vaccines, the polysaccharide is attached to a toxoid protein (see Toxoid vaccines above), helping to generate a stronger immune response to the polysaccharide alone. Examples include hib vaccine, meningitis C, men ACWY.
Recombinant vaccines - A small piece of DNA is taken from the virus or bacteria which encodes the antigen and is used to create the vaccine. The DNA fragment is inserted into other bacterial or yeast cells, these cells then produce large quantities of antigen (usually just a single protein or sugar) which are then purified and used as the active ingredient of the vaccine. Examples include hep B, HPV and men B.
Further information on the types of vaccines and which are currently within the NHS vaccination schedule or travel vaccinations is available here.