What is passive immunization? What are the risks?
preformed antibody
- Transiently protect a patient (e.g. immunosuppressed)
- Or alleviate an existing condition (e.g. toxin or venom exposure)
- Maternal antibody
- Risks: anaphylaxis, immune complexes
What is active immunization?
- Administering an infectious organism or parts thereof in a manner that stimulates long-term protective immunity
- Active immunity is generated
- It has memory and specificity
- Natural infection also stimulates active immunity
What are some goals of vaccination? What don’t vaccinations prevent?
- Reduce disease burden
- Reduce chance of transmission
- This limits the amount of circulating microorganism
- Leads to “herd immunity”
They prevent disease and death but not necessarily infection.
What is needed for an effective immune response against 1)EC bacteria or fungi, 2)IC bacteria or viruses, 3) toxins
- Extracellular bacteria or fungi – Antibody for C’ fixation, opsonization
- Intracellular bacteria or viruses – T cells for macrophage activation, cytolysis – Antibody for neutralization (viruses)
- Toxins – Antibody for neutralization
What are 5 types of vaccines?
Live attenuated, Inactivated, Toxoid, Subunit, Conjugate
How are live attenuated vaccines created? What kind of immune response does it create? What diseases is it used for? What are the risks?
A pathogenic virus is taken from a human and cultured in human cultured cells. The cultured virus is put into a monkey. In the monkey, the virus acquires mutations that allow it to grow into the monkey but in so doing, it can no longer grow well in humans and can be used in a vaccine.
Similar to natural infection so stimulates Ab and cellular responses (T cells)
e.g. Measles, mumps, rubella, yellow fever, varicella, Mtb
Risks: disease in young or immunocompromised pts; reversion to virulence
What do inactivated vaccines consist of? What is their safety? What immune response do they create?
Killed
- whole organisms rendered non-infectious
- stable, safer than live vaccines
- Ab+Th > CTL so not optimal for many viruses
What does a toxoid vaccine consist of? What immune response does it create?
- inactivated bacterial toxin
- neutralizing antibodies
What do subunit vaccines consist of? What is their safety? How do they work? What immune response do they create? What diseases do they work for?
- isolated protein components
- very safe
- must be mixed with adjuvant for effectiveness
these modify or alter a vaccine by mimicking PAMPs
- Th (and Ab) > CTL
Good for Hepatitis B, pertussis, s. pneumonia
What do conjugate vaccines consist of? What population are they particularly used for? How do they work?
- Two different parts of microorganisms
(polysaccharide for Ab, protein for Th)
B cell recognizes polysaccharide, internalizes the complex, then present the protein to Th cells. Th cells then activate B cells to proliferate, and they form memory cells against the polysaccharide. Without the protein, in some cases, the b cell response alone (without Th cell help) won’t be enough to develop a good immunity.
- Particularly useful for young children
What are two new types of vaccines in development?
DNA Vaccination and Recombinant Vector
How does DNA Vaccination work? What are some advantages to it? What type of immune response does it elicit?
- inexpensive and stable
- plasmid mixtures. When plasma is placed into APC, it enters genome and is transcribed and translated into proteins. The proteins are processed and then presented in MHC 1 to T cells.
- CTL > Ab
How are recombinant vector vaccines formed? What immune response do they elicit?
A recombinant plasmid with the gene of choice and a vaccinia promoter is mixed and cultured with the vaccinia virus. Through homologous recombination, the gene is placed into vaccinia virus genome and thus is expressed by vaccinia meaning immunity is created when that vaccinia virus is used as a vaccine.
- mimics natural infection
- strong cellular and humoral immune response
What factors determine when people should receive vaccines?
Factors: Maternal Ab levels, safety, relative risk of exposure
What antiviral vaccines are given in infancy?
HBV, rotavirus, poliovirus
How do kids get HBV? What vaccines exist and what kind are they?
- kids acquire infection from blood or body fluids
- Recombivax HB and Engerix-B (HBsAg subunit)
- first anti-cancer vaccine
Why is it important to administer the rotavirus vaccine? What are its goals? Compare and contrast rotateq and rotarix.
- nearly 100% infection rate by age 5
- major cause of hospitalizations
- often deadly in developing regions world-wide
- vaccine goals: reduce symptoms, then transmission
Rotateq:Genetic backbone Bovine/human rotavirus, Dosage schedule 3 doses at 2, 4, and 6 mo., oral
Rotarix: Human rotavirus, 2 doses at 2 and 4 mo, oral
What bacteria are combated by DTaP? What does it consist of? What are the different kinds of vaccines given through the lifetime? What age group accounts for the most cases of pertussis? the most morbidity?
• Diphtheria+tetanus toxoids, acellular pertussis
(inactivated toxins, additional protein component)
DTaP - full series for children 40) account for most cases
What diseases does the haemophilus influenzae B (Hib) vaccine protect against? At what age is its peak attack? What does it consist of?
- meningitis and deafness caused by H. influenza
; peak attack at 6-12 mo. - conjugate vaccine with toxoid or other bact. protein
What diseases does pneumococcus cause? What does the pneumococcal vaccine consist of?
- meningitis and pneumonia
- PCV13 (Prevnar 13) conjugate vaccine: purified
capsular polysaccharide from 13 serotypes of S. pneumoniae conjugated to a diphtheria toxin variant
What types of the influenza vaccine exist? What do they consist of?
- inactivated virus vaccine contains two A strains and one B strain (trivalent) – Fluzone for > 6 mo. of age
- live-attenuated, nasally administered form - FluMist/LAIV licensed for healthy people 2-49 years of age - recommended yearly for everyone
- new Flucelvax generated without eggs
What antibacterial vaccines are safe to be given within the first year of life?
DTaP, haemophilus influenzae B (HiB), pneumococcus.
What are two live attenuated viruses that are given starting at age 1? How effective are they?
• Measles, Mumps and Rubella (MMR)
- live attenuated viruses
- virtually eliminated measles in U.S. - incidence on the rise again ( classic example of herd immunity )
• Varicella (Varivax)
- 85% effective (breakthrough cases mild)
Why is Hep A vaccine given to children ? What puts kids at risk for infection? Who is it given to?
- To reduce the transmission of hepatitis A to adults
children <5 yrs have the highest infection rate;
asymptomatic, and so are silent reservoirs
vaccination of kids led to 70-90% decrease in
Hep A infection of adults
- For kids at risk of infection due to:
- household contact
- living or traveling to areas where incidence is high
Not necessarily given to every child.
