Transcript BCG lymphadenitis AEFIs causing concern or suspicion of vaccine

Adverse Events
Following Immunization
Dr S.M.Zahraei
Center for Disease Control
Ministry of Health and Medical Education
AEFI is a medical incident that takes place
after an immunization, causes concern, and is
believed to be caused by immunization

Vaccine reaction
 caused by vaccine’s inherent properties

Programme error
 caused by error in vaccine preparation,
handling or administration

Coincidental


Injection reaction


happens after immunization but not
caused by it a
chance association
anxiety or pain of injection not vaccine
Unknown

cause can not be determined
Cluster of AEFI
>=2 cases of the same adverse event
following immunizations related in time,
geography or in the vaccine administered
– Why is it important to monitor for
clustering?
Potential Objectives For AEFI Surveillance
System
•
•
•
•
Detect, correct, and prevent programme errors
Identify problems with vaccine lots or brand
Prevent false blame from coincidental events
Maintain confidence by properly responding to
parent/community concerns while increasing
awareness (public and professional) about
vaccine risks
• Generate new hypotheses about vaccine
reactions that are specific to the
population
• Estimate rates of occurrence on AEFI in
the local population, compared with trial
and international data (particularly for
new vaccines being introduced)
Programme Errors
• Non-sterile injection
– infection
• Incorrect preparation
– abscess (inadequate shaking)
– drug effect (use of drug instead of
vaccine/diluent)
• Injection in wrong site
– local reaction/abscess (wrong tissue
level)
– nerve damage
• Vaccine frozen
– local reaction
• Contraindication ignored
– avoidable severe reaction
Serious Events
• Anaphylactoid reaction (acute hypersensitivity reaction)
• Anaphylaxis
• Persistent (more than 3 hours) inconsolable screaming
• Hypotonic hyporesponsive episode
• Seizures, including febrile seizures
(6-12 days for measles/MMR; 0-2 days for DTP)
• Encephalopathy
(6-12 days for measles/MMR; 0-2 days for DTP)
Serious Events (cont…)
• Acute flaccid paralysis
– (4-30 days for OPV recipient; 4-75 days for contact)
• Brachial neuritis
– (2-28 days after tetanus containing vaccine)
• Thrombocytopaenia
– (15-35 days after measles/MMR)
• Disseminated BCG infection
• Osteitis/osteomyelitis
THANK YOU FOR
YOUR ATTENTION
DETECTING AND
REPORTING AEFIs
Which Events To Report?
• Death, hospitalization, or other severe/unusual
events
• Toxic shock syndrome
• Severe local reaction
• Sepsis
• Injection site abscess (bacterial/sterile)
• BCG lymphadenitis
• AEFIs causing concern or suspicion of vaccine
involvement
Which Reports To Investigate?
Investigate if
• possible programme error
• serious event of unexplained cause
• above expected rate (not just numbers)
• potential damage to the immunization
programme
Certain events (toxic shock syndrome, sepsis,
abscess,and BCG lymphadenitis) are likely to arise from
programme errors and must always be investigated
Contraindications
True contraindications are rare
• Current serious febrile illness
– delay vaccine administration
• History of severe AEFI after previous dose
• Evolving neurological disease
– avoid whole cell pertussis vaccine
– (e.g. uncontrolled epilepsy)
• Type 1 hypersensitivity to egg
- avoid yellow fever & influenza but can use vaccines
made in chick fibroblasts
• Symptomatic HIV
– avoid BCG and yellow fever
Contraindications
Adopted from Plotkin pg 66-67
Vaccine
Contraindication
All vaccines
Anaphylactic reaction to vaccine or
vaccine constituent
Severe febrile illness
DTP
Encephalopathy within 7 days of
administration
Immunodeficiency, or immunodeficient
household contact*
OPV
IPV
Anaphylactic reaction to neomicin,
streptomycin or polymyxin B
* Risk benefit assessment when administered to HIV positive individuals
Contraindications
Adopted from Plotkin pg 66-67
Vaccine
Contraindication
MMR
Anaphylaxis, pregnancy,
immunodeficiency*
None
Hib
Hepatitis B
Anaphylactic reaction to common
baker’s yeast
Yellow fever
Anaphylactic reaction to egg,
immunodeficiency
* Risk benefit assessment when administered to HIV-positive individuals