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IMMUNIZATIONS
DEFINITION
• Immunization is the process of inducing
immunity artificially by either vaccination
( active immunization ) or administration of
antibody ( passive immunization ).
• ACTIVE IMMUNIZATION
• Stimulates immune system to produce antibodies
and cellular immune responses that protect
against infectious agent.
PASSIVE IMMUNIZATION
• Provides temporary protection through
administration of exogenously produced
antibody such as immune globulin.
• Also occurs naturally through transplacental
transmission of antibodies to a fetus.
• Vaccine: A product of weakened or killed
microorganism (bacterium or virus) given for
the prevention or treatment of infectious
diseases
• Toxoid : A modified bacterial toxin that has
been made nontoxic but retains the capacity
to stimulate the formation of antitoxin.
The major constituents of vaccines
1. Active immunizing agent
Single antigen : tetanus , diphtheria toxoid
Complex antigens : live viruses,killed bacteria
2. Suspending fluid
Sterile water or saline
Tissue culture fluid : egg Ag, gelatin
3. Preservatives , stabilizers , antibiotics
Added to prevent bacterial growth / stabilize
Ag
Thiomersol : mercurial subs.
Neomycin , streptomycin
4. Adjuvants
• Aluminium salt added to enhance immune
• response
• Esp. vaccines with inactive microorgs
•
eg. Hep B , Diph Tet toxoids
VACCINES ON SCHEDULE
1. Hep B : Hepatitis B( inactivated recombinant)
2. DTaP : Diphtheria & Tetanus toxoid and
acellular pertussis vaccine ( inactive)
3. DT & Td.: Diphtheria & Tetanus toxoid
4. Hib : Haemophilus influenzae b
Polysaccharide protein conjugate
5. IPV : Inactivated poliovirus vaccine
6. PCV7 : Pneumococcal conjugate vaccine
7. 23PS : Pneumococcal polysaccharide
8. MMR : Measles mumps rubella live
vaccine
9. Varicella : Chicken pox live vaccine
10. Influenza : Inactivated vaccine
11. Hepatitis A : Inactivated vaccine
Simultaneous Administration
General Rule
There are no contraindications
to simultaneous administration
of any vaccines.
Spacing of vaccine combinations not
given simultaneously
Combination
Minimum Interval
Two live injected
4 weeks
All other
None
Interference Between Live Virus
Vaccines Separated by <28 days
• Retrospective cohort study of 115,000 children
vaccinated in 2 HMOs during January 1995 through
December 1999
• Risk of breakthrough varicella 2.5 times higher if
varicella vaccine given <30 days following MMR
• No increased risk if varicella vaccine given
simultaneously or >30 days after MMR
MMWR 2001;50(47):1058-61
Intervals Between Doses
General Rule
Increasing the interval between doses of
a multi-dose vaccine does not diminish
the effectiveness of the vaccine.
Decreasing the interval between doses
of a multi-dose vaccine may interfere
with antibody response and protection.
Minimum Intervals and Ages
Vaccine doses should not
be given at intervals less
than the minimum intervals
or earlier than the
minimum age
Violation of Minimum Intervals or
Minimum Age
• ACIP recommends that vaccine doses given
up to four days before the minimum interval
or age be counted as valid
• Immunization programs and/or school entry
requirements may not accept all doses given
earlier than the minimum age or interval
Extended Interval Between Doses
• Not all permutations of all schedules for
all vaccines have been studied
• Every study of extended intervals have
shown no significant difference in final
titer
• It is not necessary to add doses or restart
the series because of an extended interval
between doses
Vaccine Adverse Reaction
• Adverse reaction
– extraneous effect caused by
vaccine
– "side effect"
• Adverse event
– any event following a vaccine
– may be true adverse reaction
– may be only coincidental
Vaccine Adverse Reactions
• Local
– pain, swelling, redness at
site of injection
– common with inactivated
vaccines
– usually mild and self-limited
Vaccine Adverse Reactions
• Systemic
– fever, malaise, headache
– nonspecific
– may be unrelated to vaccine
Live Attenuated Vaccines
• Must replicate to produce immunity
• Symptoms usually mild
• Occur after an incubation period
(usually 7-21 days)
Vaccine Adverse Reactions
• Allergic
– due to vaccine or vaccine
component
– rare
– risk minimized by screening
Contraindication
• A condition in a recipient which greatly
increases the chance of a serious adverse
event.
Precaution
• A condition in a recipient which may
increase the chance or severity of an
adverse event, or
• May compromise the ability of the vaccine
to produce immunity.
Contraindications and Precautions
Permanent contraindications to
vaccination:
• severe allergy to a prior dose of vaccine
or to a vaccine component
• encephalopathy following pertussis
vaccine
Contraindications and Precautions
Condition
Allergy to
Component
Encephalopathy
Pregnancy
Immunosuppression
Severe illness
Recent blood
product
Live Inactivated
C
--C
C
P
P
C
C
V
V
P
V
C=contraindication P=precaution V=vaccinate if
indicated
Invalid Contraindications to Vaccination
•
•
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•
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Mild illness
Antibiotic therapy
Disease exposure or convalescence
Pregnancy in the household
Breastfeeding
Premature birth
Allergies to products not in vaccine
Family history unrelated to immunosuppression
Need for TB skin testing
Need for multiple vaccines
Invalid Contraindications
Minor Illness
•
•
•
•
Low grade fever
Upper respiratory infection
Otitis media
Mild diarrhea
• Only one small study has suggested decreased efficacy of
measles vaccine in children with URI
• Findings not replicated by multiple prior and subsequent
studies
• No evidence of increased adverse reactions
Screening Questions
• Allergies to food or medication?
• How is your child today?
• Any problem after last shots?
Screening Questions
• Problems with immune system
• Anyone in household with immune
problems?
• Blood products in last year?
• Pregnant?
SPECIAL HOSTS
• IMMUNOCOMPROMISED
• Live vaccines are contraindicated
• Inactivated vaccines given per schedule
HOUSEHOLD CONTACTS
• Give MMR
• Vaccine virus is not transmitted
• Varicella also given
• Transmission of vaccine virus rare
• Disease if it develops is mild
Immunosuppression
Corticosteroids
• >20 mg per day if wt >10 kg
• >2 mg/kg per day
• NOT aerosols, topical, alternate day, short
courses
Recommendations for Routine
Immunization of HIV-infected Children
Vaccine Asymptomatic Symptomatic
Varicella
Yes
No
MMR
Yes
No
All others
Yes
Yes
Yes=vaccinate No=do not vaccinate
Yes=vaccinate No=do not vaccinate
PATIENTS TREATED WITH IG /
BLOOD PRODUCTS
• Depends on dose
• MMR / Varicella give at suggested
intervals
PRETERM INFANTS
• Immunize per chronologic age
• Use regular vaccine dosage
• Exception Hepatitis B vaccine
PREGNANCY OF RECEPIENT
• Live viral vaccines are contraindicated
• Theoretical risk to fetus
• No cases actually observed with congenital
rubella or varicella
• Termination of pregnancy is not routinely
indicated
PREGNANCY OF MOTHER OR OTHER
HOUSEHOLD CONTACT
• √ MMR vaccine : Vaccine virus not
• transmitted
• √ Varicella vaccine : Vaccine virus
transmitted
• Frequency rare
• Mild / Asymptomatic infection
RECEPIENT IS BREASTFEEDING
• No vaccine is contraindicated
• Only rubella vaccine virus isolated from
human milk.
EGG ALLERGIES
• MMR vaccine can be given without prior
skin testing
• Influenza contraindicated if immediate
hypersensitivity reaction to eggs
Vaccine
Minimum age
for first dose
Minimum age from dose to dose
Vaccine
Minimum age
for first dose
Minimum age
from dose to
dose
2 to 3
3 to 4
DTaP
6 WKS
1 MONTH
1 MONTH
6 MONTHS
Hib
6 WKS
1 MONTH
1 MONTH
2 MONTHS
PCV7
6 WKS
1 MONTH
1 MONTH
2 MONTHS
IPV
6 WKS
1 MONTH
1 MONTH
1 MONTH
MMR
12 MONTHS
1 MONTH
HBV
BIRTH
1 MONTH
VARICELLA
12 MONTHS
1 MONTH
2 MONTHS
• Alex is a 1 month 25 day old infant who
received his Hepatitis B #1 at birth and is
here for a well visit. Is he due for any shots
and can he get them today ?
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•
•
2 month visit :
DTaP#1 Hib#1 IPV #1 PCV7#1
Does he have to return in 5 days for these?
Can he get HBV #2 today ?
• Alex comes back for a sick visit at age 2
months 20 days.( 25 days later) He has a
stuffy nose and is coughing with an
axillary temperature of 99 F.
• Can he get his DTaP #2, Hib # 2, IPV #2
and HBV #3 today ? Mom is keen on
getting them as it will save her an extra
trip.
4 month visit
•
•
•
•
DTaP # 2
Hib # 2
IPV# 2
PCV7 # 2
• Alex comes back at age 4 months. His mother
reported that his thigh was red and swollen after
his previous shots.
• There is a strong family history of allergies
including penicillin allergy. His older brother
Josh had a “ bad” reaction after DTaP.
• Josh’s whole leg had swelled up and he had run a
high fever too. Can Alex still get his shots ?
ADVERSE REACTIONS to
DTaP
• Minor
• 2° to pertussis component
– Redness edema pain induration at inj site
– drowsiness fussiness crying
– Anorexia vomiting
– slight to moderate fever
MINOR REACTIONS
– Usually occurs within several hours
– of immunization
– Subsides spontaneously without
– sequelae
– Much less common with DTaP than
– DTP
– NOT CONTRAINDICATIONS
ALLERGIC REACTION
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Anaphylaxis: 2 cases per 100,000
IS A CONTRAINDICATION
Transient urticarial reactions
Not anaphylactic ( IgE ) unless seen within
minutes
• Serum sickness reaction
• Unlikely to recur
• NOT A CONTRAINDICATION
Contraindications to DTaP
• 1. Immediate anaphylaxis to vaccine
• 2. Encephalopathy within 7 days
• Coma , decreased conciousness prolonged
sx
• 3. Progressive neurologic disorder
• infantile spasms, progr. encephalopathy
• uncontrolled sx
PRECAUTIONS
• These conditions may increase chance of
adverse events
• Do not cause permanent sequelae
• Weigh risk versus benefit
• Community outbreak, foreign travel
PRECAUTIONS for DTaP
• 1. Seizure ± fever within 3 days of DTaP
• Incid 1 in 1750 for DTP
• 2. HHE or hypotonic-hyporesponsive
episode : Collapse or shock like state
within 48 hrs
• Incid 1 in 1750 for DTP
• 3. Fever >= 40.5 C ( 104.8 F ) within 48
hrs. Incid 0.3%
PRECAUTIONS for DTaP
• 4. Persistent severe inconsolable screaming
/ crying for three or more hours within 48
hrs.
DTaP NOT
CONTRAINDICATED
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F/H of Seizures
F/H of SIDS
F/H of adverse reactions to DTaP
Stable neuro conditions
CP, well controlled sx, develop delay
Hx of PCN allergy ,relatives with allergy
IN PERSPECTIVE
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DISEASE
Diphtheria
Death 1 in 20
Tetanus
Death 3 in 100
Pertussis
• Pneumonia 1 in 8
Encephalitis 1 in 20
Death 1 in 200
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VACCINE
Continous crying with
full recovery 1 in 100
Convulsions or shock
then full recovery
1 in 1750
Acute encephalopathy
0-10.5 in 1,000,000
Death none proven
• Alex comes back at 6 months for a well
visit. What shots does he need ?
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6 MONTHS
Hep B # 3 ( Min age 6 mo & 4mo after 1st )
DTaP # 3
Hib # 3
IPV # 3
PCV7 # 3
• Alex will be 1 year old tomorrow. Mom
does not want to give him shots on his
birthday so can he get them today?
• Also she has heard that MMR has egg in it
and he breaks out with hives when he eats
eggs. Can he get the MMR ?
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1 YEAR OLD
Hib # 4 ( Min age 1 yr ;2 mo after 3rd dose)
MMR # 1 ( Min age 1 yr )
Varicella ( Min age 1 yr )
PCV7 # 4 ( 2 mo after 3rd dose )
MMR Vaccine
• Live attenuated
• Measles & Mumps : Chick embryo cell
culture
• Does not have significant egg white
• ( ovalbumin ) cross reacting protein
• Rubella : Human diploid cell culture
ADVERSE EVENTS
• MINOR ( after 7-12 days )
• 1. Fever >= 39.4 C ( 103 F )
• Lasts 1-5 days
• O/w Asymp
•
5-15 %
• 2. Transient rash 5%
ADVERSE EVENTS
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Moderate to severe
1. Febrile seizures
Simple feb sx
Not at increased risk of epilepsy
2. Transient thrombocytopenia
2-3 weeks after ( upto 2 months )
1 in 25,000 – 1 in 40,000
Past/H of tcytopenia / vaccine tcytopenia
3. Encephalitis / Encephalopathy < 1 in million
CONTRAINDICATIONS
• 1. Anaphylaxis to prior vaccine
• 2. Anaphylactic neomycin or gelatin
allergy
• 3. Pregnancy
• 4. Immunocompromised states
• Alex returns for his 15 month check up.
• Mom says that he broke out with chicken
pox 3 weeks after his last set of shots.
• She was worried because her nephew who
has leukemia was staying with them at the
time.
VARICELLA
• MISCONCEPTIONS
• 1. Chicken pox is a mild disease
• FACT 10,000 Hospitalizations and 100
deaths / year
• 2/3 rds the admissions and half the deaths
occur in children
• Most imp risk factor for invasive GAStrep
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2. Vaccine is not very effective
FACT : 85-90 % effective during outbreaks
100% effective agnst severe disease
Mild varicella like illness in 1-4% of immunized
kids with rapid recovery
• Rash so mild that it may resemble insect bites
• Child is potentially infectious
• 3. Immunity does not last lifelong
• FACT Protection for at least 11 years in US
and 20 years in Japan
• Other live viral vaccines : Immunity lasts a
lifetime
• 4. Is it a safe vaccine ?
• YES Reactions are mild
• Minor inj site 20%
• Local rash 3-5 %
• Gen varicelliform rash after 5-26 days in
• 3-5 %
• Zoster like illness 2.6 / 100,000 vaccine
• doses distributed
• 15 MONTHS – 18 MO
• DTaP # 4
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4-6 YEARS ( PRE KINDERGARTEN )
DTaP # 5
IPV # 4
MMR # 2
• 11 yrs
• Td
• Booster every 10 yrs
TAKE HOME MESSAGES
• Vaccines are safe
• Vaccines are very effective
• Educate yourself so that you do not propagate
misconceptions
• Ask yourself “ Is the child more likely to die of
the vaccine or the disease?” before you with hold
any vaccines
• Threat from vaccine preventable diseases is real
• Vaccination is one of
the greatest
achievements of
medicine
• It has spared millions
of people the effects
of devastating disease