Live Attenuated Vaccines

• Live vaccines are obtained by attenuating the disease-causing virus or bacteria in the laboratory.
• The microorganism in this vaccine type has the ability to multiply inside the body and induce an immune response.
• The antigen enables recognition of a substance by the immune system.
• Live vaccines should not be administered to pregnant women or people with a weakened or suppressed immune system.
• Examples of live vaccines are yellow fever vaccine, rotavirus vaccine, BCG vaccine, oral polio vaccine (OPV), Measles, Mumps and Rubella (MMR) (MMR) vaccine, and chickenpox vaccine.

Inactivated Vaccines

1. Toxoid Vaccines

• Toxoid vaccines contain a form of toxin produced by toxin producing microorganisms. However, the disease-causing properties of the toxin are eliminated by changing the toxin structure, while the immunity-inducing properties are preserved.
• Diphtheria and tetanus vaccines are toxoid vaccines.

2. Whole-Cell Vaccines

• Whole-cell vaccines contain a whole microorganism in an inactivated state.
• They are obtained by killing the microorganism produced in the culture medium by applying heat or chemicals.
• Examples are hepatitis A vaccine and inactivated polio vaccine (IPV).

3. Fractional Vaccines

• Fractional vaccines contain only certain parts of an inactivated microorganism.

3.1. Protein-Based Vaccines

• Protein-based vaccines incorporate purified microbial protein structures or microbial protein structures obtained by recombinant technology.

3.1.1. Split Vaccines

• Split vaccines contain a part of microorganism after it is disrupted or split.
• Inactivated flu vaccine is a split vaccine.

3.1.2. Subunit Vaccines

• Subunit vaccines contain certain antigenic parts of the microorganism.
• Hepatitis B vaccine and acellular pertussis vaccine are subunit vaccines.

3.2. Structural Vaccines Without Genetic Information

• This type of vaccine contains the entire capsid of the virus, but does not contain any of its enzymes or nucleic acids.
• E.g. the HPV vaccine.

3.3. Polysaccharide-Based Vaccines

• This type of vaccine is composed of long chains of polysaccharides forming the bacterial capsule.

3.3.1. Pure Polysaccharide Vaccines

• Examples are pneumococcal vaccine and meningococcal vaccine.

3.3.2. Conjugate Polysaccharide Vaccines

• Examples are pneumococcal conjugate vaccine, meningococcal conjugate vaccine and Hib vaccine.

Vaccines Containing mRNA and DNA

• mRNA Vaccines are vaccines that contain mRNA of the antibody-producing antigenic structure of the target microorganism.

  (Examples: COMIRNATY- Pfizer Biontech mRNA vaccine, Moderna mRNA vaccine)

• DNA Vaccines are vaccines that contain DNA of the antibody-producing antigenic structure of the target microorganism.

Vector Vaccines

• Vector vaccines are developed by adding the genetic information of the antibody-producing antigenic structure of the target microorganism to modified viruses. (Sputnik-V, ZEBOV, AZD1222)