Vaccination

• Deliberate introduction of antigens into body to stimulate an immune response and provide active artificial immunity; immunisation: getting the vaccine and becoming immune to the disease; all of its forms work in the same way
• Ideal vaccine: Able to induce an adequate/appropriate immune response without an active infection; safe, inexpensive, stable (not refrigerated), and easy to administer
• Primary response: Lymphocytes make antibodies and T/B memory cells, which remember pathogen (immunological memory) if it re-enters; secondary response: Faster, more effective, and increased (longer-lived) antibody production
• Vaccination Programmes

  • Herd vaccinations: Provide immunity to ~80-85% of at-risk population, second (or third) ‘booster’ doses given to increase antibody and memory cell levels higher than primary response, needed as numbers decrease over time
  • Ring Vaccinations: Involves vaccinating all those in the immediate vicinity of a new reported case of a disease
• Everyone should be vaccinated for herd immunity, but some have priority; pregnant women (antibodies transfer to foetus), health workers, those with underlying health issues (HIV, CHD, transplantation, chemotherapy, diabetes, etc), or live close to outbreaks
• We vaccinate because of the loss to the economy from days off work, higher costs to treat ill people than to buy the vaccine and eliminate the disease
• Developing vaccines can be challenging due to biological factors such as different strains, life cycle stages, antigen concealment (parasites), and limited immunity, which can be lost without further exposure or booster vaccination