L2.7.5: Types of Vaccines

• Live Attenuated Vaccines

  ● Contains a version of the whole living microbe that has been weakened in the lab so that it can’t cause disease and can’t reproduce

  ● Immunity mostly for viruses

  ● Examples: Vaccines against measles, mumps, and chickenpox
• Inactivated Vaccines

  ● Killing the whole disease-causing microbe with chemicals, heat or radiation, which is then injected into the body

  ● Do not usually offer life-long immunity (need topping-up over time)

  ● Some vaccines are meant to be inactivated, rather than just weakened, because once activated, it may cause a pathogenic response.

  ● Examples: Vaccines against influenza, polio, hepatitis A, and rabies
• Conjugate Vaccines

  ● Unlike Live Attenuated and Inactivated Vaccines, these use only a certain part of the microorganism ● For example, Peptides (the spikes surrounding the microorganism) are one of the commonly used parts for vaccines.

  ○ For conjugate vaccines, the parts they use vary
• Conjugate Vaccines

  ● Conjugate vaccines use the outer antigen coat of the bacteria or virus.

  ● These coats use a combination of a weak antigen coat and strong carrier protein = Triggers immune system to release antibodies

  ○ Weak antigen coats for conjugate vaccines usually comprise of polysaccharides (sugar molecules)

  ➢ These carbohydrates are needed so that the body may find a response for it for a longer period of time.

  ● Examples: Haemophilus Influenzae Type B Vaccine
• DNA Vaccines

  ● Creates a specific antigen from a microorganism

  ● Dispense with both the whole organism and its parts and get right down to the essentials: microbes genetic material

  ○ The activity is embedded in the nucleus of the microorganism
• DNA Vaccines

  ● Once injected into the body, the DNA from the microorganism is reproduced by the body and recognized by the immune system, generating an immune response

  ● Examples: Influenza vaccine, COVID-19 Vaccines
• Recombinant Vector Vaccines

  ● Works as a natural infection by reproducing a live virus that has been engineered to carry extra genes from the germ infecting the body

  ○ Extra number of genes produce proteins that the immune system needs to recognize and protect against
• Recombinant Vector Vaccines

  ● Vector - Virus or bacterium as the carrier

  ● They use an attenuated virus or bacterium to introduce microbial DNA to cells of the body

  ● Examples: DPT, Pentavalent Vaccine, HIB, Hepa-B
• OTHER TYPES:

  ● Toxoid Vaccines

  ○ There are several other bacteria that produce toxins in the body. The toxins will be the ones used to trigger an immune response.

  ○ Ex: Tetanus Toxoid Vaccines