Immunizations Flashcards
Active immunity
Production of antibodies in response to an antigen. Active immunity can result from exposure to a pathogen or through immunization that occurs with exposure to either a toxin or toxoid
Passive immunity
Antibodies obtained from an outside source. Examples of passive immunity are maternal-fetal transfer of antibodies and the administration of antibodies such as IVIG
Immunogenicity
The ability of a particular substance, which is called the antigen, to provoke an immune response
Efficacy
How well a vaccine protects against a dz state. A vaccine if effective if there is a reduction in dz cases resulting from the administration of the vaccine
Herd immunity
The protection of non-vaccinated ppl that results from those who get the immunizations
General principles of vaccines
The closer a vaccine is to the dz-causing form of the organism, the better the immune response of the vaccine
All vaccines can be administered at the same visit as all other vaccines
If not given at the same visit, live parenteral and intranasal vaccines should be separated by at least four weeks
Increasing the interval between doses of a multidose vaccine does not diminish the effectiveness of the vaccine
Vaccine doses cannot be divided into partial doses
The only universal absolute contraindication is hx of anaphylactic rxn to a vaccine
False contraindications to vaccination
Mild illness Antimicrobial therapy Dz exposure or convalescence Breastfeeding Preterm birth Allergy to products not present in vaccine or allergy that is not anaphylactic FHx of adverse events Tb skin testing Multiple vaccines
Example of a toxoid vaccine
TdaP
Example of a polysaccharide vaccine
Typhoid polysaccharide vaccine
Old meningococcal
23-valent pneumococcal
Example of a conjugated vaccine
Hib
Meningococcal polysaccharide vaccine
Example of a whole bacterial vaccine
Old pertussis
Typhoid vaccine inactivated
Example of a whole virion vaccine
IPV
Whole influenza vaccine
Japanese encephalitis
Both rabies vaccines
Example of a split-virion vaccine
Split-virion influenza
Hep A
Example of a recombinant vaccine
Hep B
HPV
What are the two kinds of live viral vaccines?
Enteral/intranasal
Parenteral
Example of an enteral/intranasal vaccine
Live-attenuated influenza
Rotavirus (OPV)
Example of a parenteral live vaccine
Varicella zoster
MMR
Yellow fever
Example of live bacterial vaccine
Typhoid Ty21a
BCG
Details of Hep B virus
Viral hep with long-term fatality rate approaching 100% after congenital infection Recombinant vaccine (HbsAg) starting at birth Recommended for all infants starting at less than or equal to 12 hours of age 3 doses at 0, 1, 6 mos Antibody wanes over years, but auto-boost results in prolonged efficacy
Details of rotavirus
Viral agent of severe gastroenteritis in children <2 yo
Live pentavalent bovine/human reassortant vaccine licensed for age 6-32 wks
3 doses at 2, 4, and 6 mos protect for at least 2 seasons
Details of TDap
Tetanus risk related to hygiene, vaccine status (no herd immunity)
Diphtheria and pertussis risks depend on exposure (herd immunity occurs)
Trivalent combined toxoids, available in several combinations
-D= high-dose diphtheria (children <7 yo)
-d= low-dose diphtheria (7 and older)
-aP or ap= acellular pertussis (all current formulations)
Give DTaP at 2, 4, 6, and 18 mos, 4-6 yrs, then TdaP every 10 yrs starting at 11.
Details of hib virus
Until the advent of universal immunization, the MC bacterial cause of meningitis in infants and children <5 yo
Conjugated polysaccharide vaccine cannot be given to infants < 6 wks old
Natural exposure results in near-universal immunity by age 5
Routinely given at 2, 4, (6), 12-15 mos
Details of pneumococcus vaccine and virus
MC bacterial agent of meningitis and bacteremia in children exposed to the community (>6 wks old)
MC bacterial agent of otitis media; also a common agent of pneumonia
Two licensed vaccines:
7-valent conjugated polysaccharide for age 6 wks to 4 yrs (PCV-7)
23-valent polysaccharide for age 5 and older (PPV)
PCV-7 is routinely given at 2, 4, 6, 12-15 mos
Details of polio virus and vaccine
Currently virus does not circulate in the western hemisphere
Immunization prevents reestablishment and protects travelers
IPV is the only vaccine used in the US: trivalent, inactivated, whole-viron vaccine
Routinely given at 2, 4, and 6-18 mos, 4-6 yrs
May require boosting for high-risk adult travelers
MMR details- viruses and vaccine
All 3 viruses return in sporadic outbreaks esp in teens and young adults
High risk of congenital infection
Parenteral, live-attenuated viral vaccines
Available as MMR, singly, in pairs, and with varicella as MMRV
2 doses at least 4 wks apart confer lifelong immunity
Routinely given at 12-15 mos and 4-6 yrs; not for use in infants <1 yo bc of possible interference from maternal antibody
Occasionally, children will run a fever after receiving MMR
Details of varicella virus and vaccine
Still occurs sporadically in all areas
The MC communicable human pathogen known
Occasionally fatal
Parental, live-attenuated viral vaccine
2 doses at least 4 wks apart confer lifelong immunity
Routinely given at 12-15 mos and 4-6 yrs; not for use in infants <1 yo bc of possible interference from maternal antibody
Details of influenza virus and vaccine
Two types A and B; C is rare. B occurs sporadically, A occurs in annual outbreaks and is more virulent
2 vaccines available: parenteral inactivated (TTV) and live-attenuated intranasal (LAV)
All vaccines are trivalent, containing two A strains and one B strain
Composition changes from yr to yr
Children < 9 yo receive 2 doses the 1st yr they receive flu vaccine
Annual vaccination is recommended for everyone age 6 mos- 17 yrs
Details of hep A virus and vaccine
Generally mild illness in healthy children
Two parenteral, inactivated vaccines available
Immunization of all children in 2nd yr of life is recommended; selected older children
2 doses, at least 6 mos apart
Antibody wanes, but long incubation period
Details of HPV virus and vaccine
Sexually transmitted virus; high-risk serotypes cause 99% of cervical cancers
Recombinant, parenteral vaccine contains antigens of HPV 6, 11, 16, 18
Given before the onset of sexual activity, prevents 70% of cervical cancers
3 doses given btwn 9 and 26 yoa
Routine is to start at age 11-12, and give doses at 0, 2, and 6 mos
Now permissive recommendation for males 9-18 to reduce the likelihood of acquiring genital warts- and herd immunity benefits
Meningococcus virus and vaccine details
Frequent cause of meningitis and fulminant sepsis; fatality rate is high in spite of good care
Most dz in US is caused by serotypes B and C
Both pure polysaccharide and conjugated vaccines are available
Both contain A, C, Y and W135 antigens. There is no type B vaccine
A single dose is recommended for pts at risk, including most college students
Immunity is short-lived (2-3 yrs)
Titers
Titers are blood tests that check your immune status to vaccinations or dzs you may have received in the past
While there is generally no harm in getting re-vaccinated, the blood titer is generally more cost-effective
Who should get a Hep A titer?
Ppl who were born in parts of the world with a higher prevalence of Hep A infection, such as many 3rd world countries
Anyone who believes to have been exposed to Hep A infection
Certain adolescents and adults in population groups such as American Indians, Alaska Natives, and Hispanics
Adults greater than or equal to 40 yoa
Who should get a Hep B titer?
Health care workers or public safety workers who have direct pt contact
Chronic hemodialysis pts
IC pts
Persons with HIV
Sex partners who have been exposed to Hep B infected person
Infants born to Hep B infected mother
Who should get an MMR titer?
Persons who travel internationally
Who should get a varicella titer?
Health care personnel or adults who are uncertain of their varicella hx
Immigrants to the US applying for permanent residency must show proof of varicella dz
Any person who lacks evidence of appropriate vaccination coverage
Who should get a rabies titer?
IC pts
Significant deviations of the vaccine schedule have occurred
The pt initiated the vaccination series with a questionable quality vaccine internationally
If the result is >0.05 IU/mL the person is considered immune
Safety issues
Encephalopathy- associated with whole-cell pertussis vaccine (no longer used)
Thimerosal-mercury-containing preservative no longer present in any routine childhood vaccine
ZERO clinical evidence to support the link between vaccines and an increased incidence of autism
Considerations
Yellow fever, MMR and influenza vaccines contain eggs
Do not give MMR, varicella, yellow fever, rotavirus, and flu to IC pts, as they are live
What vaccines are given at birth?
Hep B
What vaccines are given at 2 mos?
Hep B Dtap H. flu IPV PCV
What vaccines are given at 4 mos?
Dtap Rotavirus H. flu IPV PCV
What vaccines are given at 6 mos?
Hep B Dtap Rotavirus H. flu IPV PCV Influenza
What vaccines are given at 1-1.5 yrs?
MMR Hep A Dtap H flu IPV PCV
What vaccines are given at 4-6 yrs?
Varicella
Dtap
IPV
MMR
What vaccines are given at 11-12 yrs?
Tdap
HPV
Men?
What vaccines are given at 16-18 yrs?
Men?
Booster
