[3S] Vaccines Flashcards
VACCINE PREVENTABLE DISEASES
Introducing the antigen to a system; natural or induced.
Active Immunization
VACCINE PREVENTABLE DISEASES
Our own immune system is responsible for protecting us from a pathogen.
Active Immunization
VACCINE PREVENTABLE DISEASES
Protected from a pathogen by immunity gained from someone else.
Passive Immunization
Consists of antigen-induced formation of antibodies in the host and cell-mediated immunity.
Active Immunization
Requires time to develop → concurrent passive and active
○ Generally inactive at the time of specific exposure.
Active Immunization
Generally preferable to ____ immunization.
○ Higher antibody levels for longer periods of time
○ Less frequent immunization
○ Concurrent cell-mediated immunity
Passive
ACTIVE IMMUNIZATION
Duration of Immunity
Live vaccines > inactive vaccines
- Complete prevention of disease
- Prevention of the carrier state
- Production of prolonged immunity
- Absence of toxicity
- Mass immunization
● Inexpensive
● Easy to administer - Easy transport
- Easy storage
Ideal Immunogen
Consists of transfer of immunity to a host using preformed immunologic products
Passive Immunization / Immunoglobulins
Only used for passive immunization due to the difficulty of passive administration of cellular components of the immune system and its association with graft-versus-host reactions.
Passive Immunization / Immunoglobulins
Interferons
○ Hematologic
○ Infectious diseases
Passive Immunization / Immunoglobulins
Confer temporary immunity
Passive Immunization / Immunoglobulins
○ Antibodies from mother to fetus during pregnancy.
○ Breast milk and colostrum.
Natural
CLINICAL USES
● Individuals unable to form antibodies.
● Prevention of disease when time does not permit active immunization - post-exposure.
● Treatment of certain diseases normally prevented by immunization.
● Treatment of conditions for which active immunization is unavailable or impractical.
Passive Immunization / Immunoglobulins
COMPLICATIONS
Absolute contraindication in passive immunization
○ May develop in individuals with certain immunoglobulin deficiencies.
○ Those with IgE deficiencies are at high risk.
Hypersensitivity reactions
● Have a shorter half-life (around 20 days).
● Anaphylaxis to serum sickness
Animal Antibodies
T/F: Anaphylaxis to serum sickness is least likely to happen with highly purified immunoglobulins (e.g. rodents or lagomorphs).
T
● Lower risk of hypersensitivity reactions.
● Much longer half-life in humans (IgG 23 days vs. 5-7 days.
● Smaller doses can be administered to provide therapeutic concentration for several weeks.
Human Antibodies
Preferred option for passive protection whenever
possible.
Human Antibodies
STORAGE
Inactivated vaccines
Diluents for lyophilized vaccines (or room temp.)
Live attenuated influenza vaccine nasal spray
Refrigerator 2-8°C
STORAGE
Lyophilized-powder live-virus vaccines
Freezer -15°C or colder
VACCINE TYPE
● Weakened virus
● Reduce virulence but retain immunogenic antigens.
● Humoral and cellular responses
● Memory cells: One or two doses
LIVE ATTENUATED VACCINES
VIRUS
Measles Polio Rotavirus
LIVE ATTENUATED VACCINES
VIRUS
Yellow fever
Chickenpox
LIVE ATTENUATED VACCINES
BACTERIA
Vibrio cholera
Tuberculosis
LIVE ATTENUATED VACCINES
DISADVANTAGES
● Must be refrigerated to retain their activity.
● Can mutate in the host virulent and cause disease.
LIVE ATTENUATED VACCINES
Contraindications of Live Attenuated
● Immunocompromised individuals
● Pregnancy
VACCINE TYPE
● Kill pathogens through:
○ Heat
○ Radiation
○ Chemicals
● Replicate or mutate (safe)
● Can be freeze-dried and transported without refrigeration.
INACTIVATED VACCINES
VIRUS
Polio
Influenza
Rabies
INACTIVATED VACCINES
BACTERIA
Typhoid
Plague
INACTIVATED VACCINES
DISADVANTAGE
● Weaker immune response
● Multiple doses
INACTIVATED VACCINES
VACCINE TYPE
● Component of the microorganism
● Polysaccharides or proteins
● Considered safe because they have no live replicating pathogen present.
SUBUNIT VACCINES
VACCINE TYPE
Includes:
○ Recombinant subunit vaccines
○ Hepatitis B
SUBUNIT VACCINES
DISADVANTAGES
○ Induce a less-robust immune system
○ Lengthy and costly to develop
○ Immunity is not guaranteed
SUBUNIT VACCINES
SUBUNIT TYPE
● Sugar antigens
○ Bacterial cell walls (peptidoglycan)
● Bacterial capsule polysaccharide
○ Carrier protein (diphtheria/tetanus toxoid)
Polysaccharide
SUBUNIT TYPE
Meningococcal infection
■ Neisseria meningitidis - Group A, C, W-135, Y
Polysaccharide
SUBUNIT TYPE
Haemophilus influenzae type b (Hib)
Pneumococcal - PCV7, 10, 13
Polysaccharide
DISADVANTAGES
○ Not very immunogenic
○ Suboptimal immune responses (short-term immunity)
Polysaccharide
SUBUNIT TYPE
● T-protein-based: Purified proteins
● Includes:
○ Acellular pertussis (aP)
○ Hepatitis B vaccines (envelop protein)
Surface Protein
DISADVANTAGES
○ May not be presented in native form
○ Antibodies may not bind efficiently
Surface Protein
SUBUNIT TYPE
● Immune response bind and neutralize toxins.
● Prevents cell damage in the patient.
● Safe: No live pathogens
● Stable over a wide range of temperatures and humidities.
Toxoids
SUBUNIT TYPE
Clostridium tetani
Corynebacterium diphtheria
Toxoids
DISADVANTAGES
Not highly immunogenic
■ Adsorbed to adjuvants (Al or Ca salts) to increase their capacity to stimulate the immune response.
Toxoids
VACCINE TYPE
● Antigenic genes: Synthetic DNA
● IM or ID
● APCs
● Both humoral and cellular
DNA VACCINES
No risk of infection
Cost-effective
Stable
Long-term protection
DNA VACCINES
DISADVANTAGES
● Limit to protein antigens
● Tolerance to antigen (low immunogenicity)
DNA VACCINES
VACCINE TYPE
Vector: Virus/bacterium
○ Microbial genes
○ Infects or transduces host cells
● The protein code are being packaged.
● Replaces the natural gene with microbial gene.
RECOMBINANT VECTORS
Includes:
○ Poxviruses (vaccinia)
○ Adenoviruses
RECOMBINANT VECTORS
VACCINE TYPE
● Developed quickly using the pathogen’s genetic code.
● Change the mRNA formulation to target a new antigen.
mRNA VACCINE
Non-replicating
In vivo self-replicating
In vivo dendritic cell non-replicating
RNA-Based
Tuberculosis
Oral polio vaccine (OPV)
Measles
Rotavirus
Yellow fever
Live Attenuated (LAV)
Whole-cell pertussis (wP)
Inactivated poliovirus (IPV)
Inactivated
Acellular pertussis (aP)
Hib
Pneumococcal (PCV-7/10/13)
Hepatitis B
Subunit
Tetanus toxoid (TT)
Diphtheria toxoid
Toxoid
