6/18- Immunization for Prevention of IDs Flashcards
History of immunization: broad development of methods?
- Killed viruses -> Protein/CPS -> DNA/rDNA
Vaccine-preventable diseases?
- Smallpox
- Diphtheria
- Measles
- Mumps
- Pertussis (increase in recent cases…)
- Polio (paralytic)
- Rubella
- Congenital Rubella Syndrome
- Tetanus
- Haemophilus influenzae
General requirements for immunization (mechanistic)? Mechanism of Protection?
General requirements:
- Activation of APCs, T and B cells with generation of memory (must incorporate B and T-cell epitopes); antigen must persist
Mechanisms of protection
- Serum and mucosal Abs (prevent and facilitate clearance)
- Cell mediated immune responses (limit extent of infection and facilitate pathogen clearance)
Properties of an ideal vaccine
- Elicits relevant immune response
- Confers long-lived immunity
- Safe and well tolerated
- Stable and retains potency
- Affordable
What is passive immunization? Characteristics?
- Administration of Ig-containing material in order to prevent or modify disease
- Protection conferred immediately
- Protection generally short-lived
- Primary use: postexposure prophylaxis, or when vaccine is not available/indicated
(passive immunotherapy involving infusion of Ag-specific cells is being evaluated)
What diseases are treated with passive immunization?
Pre-exposure prophylaxis:
- CMV
- HAV
- RSV
- (ITP, IG deficiency)
Post-exposure prophylaxis:
- HAV
- HBV
- Measles
- Rabies (with vaccine)
- Rubella
- Tetanus
- VZV
Treatment:
- Botulism
- CMV
- Diphtheria
- RSV
- Lassa fever
- Tetanus
- Complications of vaccinia
- ITP
- Kawasaki disease
What is active immunization? Characteristics?
- Stimulation of protective immune responses via administration of a vaccine
- Weeks to months generally are required for responses to develop
- Protection generally long-lived (may require boosters)
- Primary use: pre-exposure prophylaxis
Two subsets of active immunization? Characteristics?
Non-replicating (inactivated, subunit, conjugate…)
- Generally safer
- Generally more stable
Replicating
- Fewer doses
- Lower antigen content
- Broader responses
- More durable immunity
What factors (vaccine and host) affect immune response to immunization?
Vaccine factors:
- Dosage and route
- Spacing of doses
- Type of antigen
- Adjuvants
- Combinations
Host factors
- Age**
- Immune status
- Genetic factors
- Medications
- Nutritional status
- Underlying diseases
**Ex) poor response to CPS antigens in infants under 2; overcome by conjugating CPS to protein (T-indep -> T-dep)
General recommendations for the timing and spacing of immunobiologics (vaccine or antibody…)?
- Observe recommended ages and minimum intervals between doses; generally no need to repeat doses if interval is exceeded
- Administer recommended vaccines simultaneously unless contraindicated
- Do not combine vaccines unless safety and immunogenicity have been assessed
Specific recommendations:
- Antigen combination: minimum interval between doses
- 2+ inactivated: simultaneous or any interval
- Inactivated and live: simultaneous or at any interval
- 2+ live (intranasal or injected)- 4 week interval if not simultaneous*
*Ty21a and rotavirus vaccine can be given together or at any interval before/after other vaccines
General Recommendations for spacing of Ab-containing products and vaccines?
- In general, antibody-containing products and LIVE vaccines should not be given simultaneously (excluding live typhoid and yellow fever vaccines and LAIV)
- Antibody-containing products and INACTIVATED vaccines can generally be given simultaneously at different sites
Examples of serious adverse events associated with biologics? Table of risk of immunizations…
- Diphtheria antitoxin contaminated with tetanus (Biologics Control Act 1902)
- Incompletely inactivated poliovirus vaccine and vaccine-associated polio (‘the Cutter Incident’)
- Inactivated measles vaccine: Atypical measles after exposure to wild type virus
- Inactivated respiratory syncytial virus vaccine: Exaggerated disease/death after exposure to wild type virus
- Rotavirus vaccine and intussusception
True contraindications to immunization?
- Hypersensitivity to component
- Moderate or severe illness (delay)
- Encephalopathy within 7 days of immunization with DTP/DTaP
- OPV: Immunosuppressed & HIV-infected persons and their contacts
- MMR: Immunodeficient patients
- Rotavirus: Patients with SCID or history of intussusception
Immunization not contraindicated when?
- Mild acute illness/convalescence
- Prior mild/moderate local reaction
- Antimicrobial therapy
- Prematurity
- Recent exposure to infectious agent
- Nonspecific/penicillin allergies
- Family history: Allergies, seizures, SIDS
Special considerations for vaccinations?
- Pregnancy
- Family Hx of immunodeficiency states
Misconceptions of long term side effects?
- Asthma
- Attention deficit disorder
- Autism
- Chronic fatigue syndrome
- Diabetes
- Inflammatory bowel disease
- Multiple sclerosis
- SIDS
T/F: The right of states to pass and enforce compulsory immunization has been confirmed and upheld?
True
Exemptions to compulsory immunization include what?
- Medical
- Religious
- Philosophical (vary by state)
What is contained in the DTaP vaccine? Recommended immunization schedule?
Diphtheria-Tetanus-Acellular Pertussis Vaccine
- Contain up to 5 pertussis components and purified diphtheria and tetanus toxoids (all proteins)
- Protection correlated with serum Ab (DT); no Ab correlate for pertussis antigens
- Primary immunization schedule: 5 doses between birth and 6 yrs
Recommendations for use of DTaP vaccine?
- Indications
- Contraindications
- Precautions
Indications:
- Universal immunization of all infants and children up to age 6 years
Contraindications:
- Encephalopathy within 7 days of receipt of previous dose
- Progressive neurologic disorder (conditional)
Precautions:
- High fever, collapse or shock-like state
- Inconsolable crying >3 hours within 2 days of prior dose
- Seizure within 3 days of prior dose
What is the Td/Tdap vaccine?
- Contents
- Uses
- Dosage schedule
- Precautions
- Inactivated toxoids (ap contains several pertussis antigens: PT, FHA, PRN, FIM 2&3
Uses:
- Routine immunization
- Wound care
- Adolescent and adult immunization
Schedule:
- Booster doses of Td or Tdap (once only) recommended for adults every 10 years
- Tdap during each pregnancy
- Tdap can be given regardless of interval since last Td for pertussis prevention; replaces next scheduled dose of Td
Precautions:
- GBS
DTaP; Tdap summary
- All infants should _____
- All adolescents and adults should _____
- Pregnant women should _____
- Travelers should _____
DTaP; Tdap summary
- All infants should be immunized with DTaP vaccine (series)
- All adolescents and adults should receive Tdap vaccine, as should children 7-10 yrs who have not been fully vaccinated
- Pregnant women should receive Tdap during each pregnancy
- Travelers should be boosted with Td or Tdap if it has been at least 5 yrs since last booster
What kind of vaccine is used for H. influenzae?
- Mechanism
- Indications
- Immunization schedule
HIB conjugate vaccine
- Protein-polysaccharide conjugates of the CPS of H. influenzae type B conjugated to one of several proteins: OMP, CRM, or TT
- Protection mediated by Ab vs. CPS
Indications:
- Universal immunization of infants Immunization schedule
- 3-4 doses over 18 months (3 for OMP-CV)
Where is polio endemic?
- Afghanistan
- Nigeria
- Pakistan
- Horn of Africa (type 2 eradicated in 1999)
Characteristics of the poliovirus vaccine? Components/mechanism
- Formalin-inactivated vaccine (IPV)
- Oral live attenuated vaccine (OPV)
Protection mediated by neutralizing Abs against the 3 serotypes
Because the risk of developing vaccine- associated polio in the U.S. is greater than the risk of infection, routine use of OPV is no longer recommended
Polio immunization:
- Indications
- Contraindications
- Risk groups
- Schedule
Indications:
- Universal immunization of infants and children (4 doses) with IPV
- Not usually recommended for persons over the age of 17 years
- Consider a 1 time booster dose for adult travelers to endemic areas.
Contraindications:
- Anaphylactic reactions to streptomycin, neomycin, or polymyxin B Risk groups:
- Non-immune travelers to Asia and Africa
- Members of communities or groups with disease caused by wild type polio
- Lab workers who handle samples containing polio
- HCW in contact with infected patients; unvaccinated adults in contact with children given
OPV Schedule for unvaccinated adults:
- 3 doses at least 4 weeks apart (0, 1-2 mo., 6-12 mo. preferable)
- 2 doses or even 1 dose can be given if time is not available
What age groups is most affected by measles in the US?
> 14 yo
(followed by 0-4 yo)
Outbreak of measles recently where?
Measles- Disneyland in CA
What age group is at greater risk for severe disease and death with measles? What should be done?
Infants
- Infants who travel or live abroad should be vaccinated at an earlier age (6-11 mo; dose doesn’t count)
Outbreak of mumps recently where?
UT Austin (7 cases)
Principles for mumps control?
- Timely vaccination with 2 doses of MMR vaccine
- High awareness among HCPs
- Ongoing surveillance and prompt reporting of mumps cases - Isolation of persons with suspected and confirmed mumps for 5 days after onset of parotitis
- In congregate settings (colleges, schools): early recognition, diagnosis, and public health intervention
- During outbreaks: 1 dose of MMR vaccine for adults and children whose vaccination status is unknown or who have not received the number of MMR doses recommended by the ACIP; consideration of a second dose of MMR vaccine for children aged 1 thru 4 years and adults who have received 1 dose
Characteristics of MMR vaccine?
- Components
- Dosage schedule
- Contraindications
- Live attenuated virus
Schedule
- Universal immunization of infants with 2 doses of MMR at 12-15 mo. and 4-6 yrs of age (dose 2 should be given at least 4 wks after dose 1)
- Children 6-12 months old traveling to endemic areas should receive a dose of vaccine prior to travel; dose doesn’t count (still need 2 doses on or after 12 mo. of age). For others born after 1980: h/o receipt of 2 doses, or verify immunity
- Update: 2 doses recommended for people born after 1956 (in post-high school educational institutions, medical personnel, and those traveling to measles-endemic areas) who lack evidence of immunity: documentation of 2 doses of MMR on/after 1st birthday, measles diagnosis with lab confirmation, lab evidence of immunity
Contraindications:
- Immune deficiency disorders (OK in HIV infxn if not severely immunocompromised)
- Anaphylactic reactions to neomycin
- Pregnancy
HIB, Polio, MMR summary
- All infants should _______
- Preferred polio vaccine is ___. Adult travelers should consider ______
- MMR vaccine: __ doses are recommended for _______ and _____.
Infants traveling to areas where ____ is occurring should be vaccinated at ____ of age.
HIB, Polio, MMR summary
- All infants should be vaccinated with HIB conjugate vaccine
- Preferred polio vaccine is IPV. Adult travelers should consider a single dose if traveling to areas where polio persists
- MMR vaccine: 2 doses are recommended for infants and certain adults who only received a single dose.
Infants traveling to areas where measles is occurring should be vaccinated at 6 months of age.
What is this?
Left: Varicella
Right: Zoster
What age groups are most affected by invasive pneumococcal disease?
- 1 yo
- Followed by under 1 yo
- Resurgence again in 65+
PCV should be used in adults when?
- 13 Valent PCV was recently licensed for use in adults ≥50 years old.
- Recommended for all persons ≥65 years old, and persons 5 thru 64 years with high risk conditions
Overall childhood immunization schedule?
