vaccination

• passive natural - breastfeeding
• passive artificial - A series of injections given against Rabies
• active artificial - A vaccine to measles, mumps and rubella (MMR)
• active natural - A patient develops a Streptococcus pneumonia
• Vaccines are a safe form of antigens injected into the blood to trigger artificial active immunity against a pathogen.

  • Killed or inactivated bacteria and viruses
  • Attenuated (weakened) versions of live pathogens
  • Altered toxin molecules from pathogens
  • Isolated antigens
  • Genetically engineered antigens
  • RNA
• Small volumes of the vaccine (the altered or safe antigen) are injected into the body.
• epidemic - A communicable disease spreads rapidly across a local or national level
• pandemic -  A communicable disease spreads rapidly across a number of countries and continents.
• Mass vaccination can prevent spread and over time can lead to herd immunity.

  Herd immunity arises when a sufficiently large proportion of the population has been vaccinated and are immune. This makes it difficult for a pathogen to spread within that population. Those who are not immunised are protected and unlikely to contract it as the levels of the disease are so low
• If vaccination rates fall below the required level then herd immunity can falter. This has been seen with some of the childhood vaccination programmes due to low uptake in some areas of the country or due to issues during the pandemic
• • Some vaccines contain a dead or weakened form of a pathogen.
  • The antigens on the cell surface of the pathogen are still able to trigger the production of specific antibodies in the person being vaccinated.
  • Cells called memory cells are also produced, which retain the ability to divide and produce the antibodies quickly, should the pathogen return.
  • A new strain of pathogen can arise if there is a mutation in the DNA of the pathogen. If this happens, the original vaccine is not likely to be effective.