immunizations. definition immunization is the process of inducing immunity artificially by either...
TRANSCRIPT
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 vaccines1. 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 , antibioticsAdded to prevent bacterial growth / stabilize AgThiomersol : 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 RuleThere are no contraindications to simultaneous administration of any vaccines.
CombinationTwo live injected
All other
Minimum Interval4 weeks
None
Spacing of vaccine combinations not given simultaneously
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 RuleIncreasing 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
• severe allergy to a prior dose of vaccine or to a vaccine component
• encephalopathy following pertussis vaccine
Permanent contraindications to vaccination:
Contraindications and Precautions
ConditionAllergy to ComponentEncephalopathyPregnancyImmunosuppressionSevere illnessRecent blood product
LiveC---CCPP
InactivatedCCVVPV
C=contraindication P=precaution V=vaccinate if indicated
Invalid Contraindications to Vaccination
• 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 ContraindicationsMinor 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
• >20 mg per day if wt >10 kg
• >2 mg/kg per day
• NOT aerosols, topical, alternate day, short courses
Corticosteroids
Recommendations for Routine Immunization of HIV-infected Children
VaccineVaricellaMMRAll others
AsymptomaticYesYesYes
SymptomaticNoNoYes
Yes=vaccinate No=do not vaccinateYes=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 2 MONTHS
VARICELLA 12 MONTHS 1 MONTH
• 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 ?
• 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
• 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
• 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
• DISEASE
• Diphtheria
• Death 1 in 20
• Tetanus
• Death 3 in 100 Pertussis
• Pneumonia 1 in 8 Encephalitis 1 in 20 Death 1 in 200
• 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 ?
• 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 ?
• 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 )
• Live attenuated
• Measles & Mumps : Chick embryo cell culture
• Does not have significant egg white
• ( ovalbumin ) cross reacting protein
• Rubella : Human diploid cell culture
MMR Vaccine
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
• 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
• 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
• 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