IMMUNISATION
PART 1
Father of Modern
Immunization Edward Jenner
IMMUNIZATION AGAINST
SMALLPOX
Protective mechanisms
• INNATE IMMUNITY
– Skin, mucosal barrier
– Natural Killer (NK) cells
– Phagocytes
• ADAPTIVE IMMUNITY
-B lymphocytes
- T lymphocytes
Vaccines stimulate adaptive immunity
OTHER TYPES OF IMMUNITY
• Active immunity- by natural infection.
– Takes longer to be established
• Passive immunityantibodies
passive
transfer
– Is immediate, short lived
• Humoral immunity- by B lymphocytes
• Cell mediated immunity- by T lymphocytes
of
HOW DO VACCINES WORK?
• -IMMUNE response in the body
• Humoral or antibody mediated
• immunityneutralization,
complement
activation, opsonophagocytosis
• Types of antibodies- IgG, IgM, IgA, IgE
HOW DO VACCINES WORK?
• CELL MEDIATED IMMUNITY
• Essential for protection
• T lymphocyte mediated
– Helper T cells
– Cytotoxic T cell
• Helper T cell- cytokine production
• Longer lasting and robust immunity
TYPES OF VACCINES
• Various types of vaccines which produce
differing immune responses
• Killed vaccines- inactive microbe
• Toxoid- eg tetanus, diphtheria
• Subunit vaccines- Hib,
• Conjugate vaccines- typhoid
• Recombinant vaccines- Hepatitis B
• Live attenuated vaccine- Rotavirus, Oral polio
TYPES OF IMMUNE RESPONSES
• Of 2 types
• Primary response
– Rapid increase of IgG after antigen exposure
– Peak levels after 4 weeks
– Return to baseline after wards
• Secondary response
- upon re-exposure to antigens
- B cell reactivation, long lived plasma cells
survive in bone marrow
BOOSTER DOSES
• Immune memory occurs due to memory B
cells
• Repeated doses or natural exposure activate
them
• Immune memory cells activated after 4-7 days
• Regular booster doses for diseases with short
incubation periods eg Hib, Tetanus, etc
• Live vaccines like Hep. A , do not require
boosters- long incubation period
BOOSTER DOSES
• Killed vaccines do not produce robust and long
lasting immune responses. Booster doses
improve the protection Eg. DTP
• Polysaccharide vaccines do not induce long
lasting immunity. Booster doses are essential for
continued protection. Eg Vi polysaccharide
Typhoid vaccine
• Oral vaccines may not produce 100% protection
with a single dose. Hence repeated doses are
recommended. Eg Oral polio, Rotavirus vaccine
CATCH UP IMMUNIZATION
• In case patient has taken one dose of a vaccine
and missed the subsequent doses, you must
continue and complete the remaining doses as
per the schedule. NO NEED to RESTART the entire
immunization.
• HAV 2nd dose can be given upto 2 years after the
first dose
• Rotavirus vaccine must NOT be given beyond the
scheduled time- 1st dose by 14 weeks 6 days and
2nd dose before 6 months, 3rd dose by 8 months
maximum
CATCH UP IMMUNIZATION
• In case of Missed vaccines, catch up
immunization recommended
• Simultaneously administer 2 inactive vaccines
• Inactive vaccine simultaneous / after any
interval with a live vaccine
• Two live vaccines- administer simultaneously
/after an interval of 4 weeks
IMPACT OF IMMUNIZATION AT
YOUNGER AGES
• Early protection required
• Accelerated immunization schedule
• Vaccines at birth and 6 weeks act as priming
doses
• Subsequent doses at 6-8 weeks interval
• Produce good immune responses
• BCG at birth because better T cell responses
Vaccine preventable causes of death
worldwide in children <5yrs
In 2008, WHO estimated that 17% of global U5M were due to
vaccine preventable diseases
DISEASE BURDEN- INDIA is the
epicenter of childhood mortality
*Each dot represents 5000 deaths
Relevance of IMMUNIZATION
• Immunization is an important tool to decrease
the childhood mortality
• Immunization coverage in India continues to
remain very poor
• According to 2009 Coverage Evaluation Survey
only 61% of children between 12-23 months
were fully vaccinated(BCG, Measles, 3 doses DPT
and polio)
• There is a large role for DOCTORS to improve
the immunization acceptance rate
TAKE HOME MESSAGE
• Immunization is a potent tool for controlling and
eradicating disease.
• Types of immunity include innate, adaptive,
active, passive, humoral and cell mediated
immunity
• Types of vaccines include, Live attenuated, killed,
toxoids, recombinant and conjugated
• Some vaccines require boosters to maintain
adequate protection
• Catch up immunization is needed for missed
doses.
WHAT IS COLD CHAIN?
• System of transporting, storing and
distributing vaccines
• Ensuring proper temperature maintenance
from point of manufacture till end user
• Important to maintain the chain without
breaks
• No substitute for rigorous maintenance of cold
chain
COMPONENTS OF COLD
CHAIN
• ESSENTIAL Components:
– Personnel responsible for vaccine distribution
– Appropriate equipment to store vaccines
– Appropriate transport facilities
– Maintain equipment well
– Monitoring of the systems
• Every link is important and
maintained accurately
must be
Effect of temperature
• Both heat and cold in excess can affect vaccine
potency
• All vaccines are sensitive to heat- loss of
vaccine potency
• Live vaccines more susceptible to heat
MMR, Oral POLIO, Varicella, BCG, Measles
Effect of temperature
• Freezing of vaccines- deleterious effects
• Aluminium adjuvant containing vaccines more
susceptible to damage
eg,. DTwP, TT, Hepatitis A, HPV, PCV etc
• Some vaccines are not harmed by freezing
Eg BCG, OPV, MMR, Varicella, MMRV
Effect of light on vaccines
• Direct sunlight exposure is harmful
• Also, fluorescent neon light, ultraviolet light,
any strong light
• Vaccines easily damaged by light exposure
include BCG, MMR, Measles, Rotavirus, HPV,
DTaP
VACCINE MONITORS
Indicators
• Freeze watch indicators
• Vaccine vial monitors
(VVM)
• Dial/ stem/ electronic
Thermometers • Maximum- minimum
VACCINE VIAL MONITORS
(VVM)
• Sensitive to temperature and time
• Placed outside the vaccine vial
– Inner square white/ lighter than outer circlepotent vaccine , if not expired
– Inner square color matches /darker than outer
circle- DISCARD IMMEDIATELY
• Useful indicators in out reach programs
VACCINE VIAL MONITORS
VACCINE MONITORS-FREEZE
WATCH INDICATORS
• Small red liquid filled vials attached to a white
card. Covered in plastic
• Explodes if ambient temperature < 0°C
• Useful to maintain vaccines that should not be
frozen
DTwP, DTaP, Hepatitis B etc
FREEZE WATCH INDICATORS
THERMOMETERS
•
•
•
•
•
Handy monitoring tool for vaccine efficacy
Place in the midst of vaccines
Continuous monitoring of temperature
Temperature log twice daily
Use Calibrated and certified thermometer
THERMOMETERS
COLD CHAIN EQUIPMENT
• Consists of 2 arms:
Set chain
• Walk in cold
rooms
• Deep freezers
• Refrigerators
Mobile chain
• Iso-thermic
boxes
• Vaccine
carriers
COLD CHAIN EQUIPMENT
• Walk in cold rooms- and freezers used for bulk
storage at site of manufacture/ bulk
distribution
• Deep freezers- long term vaccine storage eg
OPV, MMR
• Domestic refrigerators- in office practice
temperature between 2-8°C
• Double door preferred
VACCINE PLACEMENT
•
•
•
•
NO VACCINES ON THE DOOR
Freezer: OPV
Top shelf: BCG, Measles, MMR
Middle: DTwP, DTaP, HPV, DT, TT, IPV, PCV, HAV,
Influenza, Rota, Combination vaccines
• Lower: HBV, Varicella
• Crispator: Diluents
• Baffle tray: EMPTY
VACCINE PLACEMENT
COLD BOXES, VACCINE
CARRIERS
VACCINE STORAGE
•
•
•
•
Protect from direct sunlight
Safe storage in original packs till use
Temperature 2-8°C for 24 months
Live vaccines kept frozen for longer use- MMR,
OPV, BCG, Measles
• DISCARD accidentally frozen vaccines
• NEVER freeze diluents
TIME LIMIT FOR
RECONSTITUTED VACCINES
•
•
•
•
•
•
•
•
Varicella: 30mins- protected from light
MMRV : 30mins- protected from light
Yellow Fever: 1 hour
MMR/ Measles: 4-6 hours
DTaP/ Hib combination: 30 mins
Meningo- polysaccharide: 30 mins
Opened DTP, TT, OPV, HBV: Within 1 month
BCG, MVAC, Yellow fever: max 6 hours/ end of
immunization session
Take Home message
• Cold chain is an important method of
maintaining vaccine potency
• The cold chain must be maintained from point
of manufacture till the end use.
• Each vaccine must be stored appropriately in
the refrigerator
• Vaccine carriers must be properly used to
carry vaccines to the field.