Transcript Adverse Events Following Immunization, AEFI

Adverse Events Following
Immunization, AEFI
AEFI
WHAT IS AN AEFI?
AEFI IS A MEDICAL INCIDENT AFTER
AN IMMUNIZATION AND IS BELIEVED
TO BE CAUSED BY THE
IMMUNIZATION
BASICALLY TWO TYPES
AVOIDABLE AND UNAVOIDABLE
AEFI
MODERN VACCINES
 ARE GENERALLY SAFE
 NOT ENTIRELY WITHOUT RISK
 BENEFITS FAR OUTWEIGH RISKS
AEFI
WHY MONITORING OF AEFI ARE
IMPORTANT ?
 UPSETS PEOPLE
 REFUSAL FOR FURTHER IMMUNIZATION
AEFI
CLASSIFICATION OF AEFI
 VACCINE EFFECT
 PROGRAMME ERROR
 COINCIDENTAL
 INJECTION REACTION
 UNKNOWN
AEFI
THE USEFULLNESS OF MONITORING AEFI
 TO IDENTIFY PROGRAMME ERRORS
 IDENTIFY VACCINE DEFECTS
 TAKE CORRECTIVE MEASURES
 INCREASE IMMUNIZATION ACCEPTANCE
 IMPROVE THE QUALITY OF SERVICES
AEFI
AEFI ARE DUE TO:
1 VACCINE
EVENT CAUSED OR PRECIPITATED BY
THE VACCINE WHEN GIVEN
CORRECTLY, CAUSED BY THE
INHERENT PROPERTIES OF THE
VACCINE
AEFI
2 PROGRAMME ERROR
EVENT CAUSED BY AN ERROR IN
VACCINE:
 PREPARATION
 HANDLING
 ADMINISTRATION
AEFI
3 COINCIDENTAL
EVENT THAT HAPPENS AFTER
IMMUNIZATION BUT NOT
CAUSED BY THE VACCINE – A
CHANCE ASSOCIATION
AEFI
4 INJECTION REACTION
EVENT FROM ANXIETY ABOUT, OR PAIN
FROM THE INJECTION ITSELF RATHER
THAN THE VACCINE
5 UNKNOWN
THE CAUSE OF THE EVENT CANNOT
BE DETERMINED
AEFI
SURVEILLANCE
1. DETECTION AND REPORTING
2. INVESTIGATION
3. DATA ANALYSIS
4. CORRECTIVE ACTION
5. EVALUATION
AEFI
HOW CAN AEFI’S BE
DETECTED?
WHAT MECHANISMS ARE
AVAILABLE?
AEFI
LIST OF AEFI
1. LOCAL ADVERSE EVENTS
2. CNS ADVERSE EVENTS
3. OTHER ADVERSE EVENTS
AEFI
LOCAL ADVERSE EVENTS
1.INJECTION SITE ABSCESS
STERILE
BACTERIAL
AEFI
FORMATION OF A STERILE ABSCESS
1. WRONG ROUTE (SC INSTEAD OF DEEP IM)
2. NOT SHAKING THE VACCINE BOTTLE BEFORE
DRAWING IN TO THE SYRINGE
3. WRONG DOSE (LARGER DOSE)
AEFI
2. LYMPHADENITIS
AT LEAST ONE LYMPH NODE 1.5
CM IN SIZE OR DRAINING SINUS
OVER LYMPH NODE 2 – 6
MONTHS AFTER BCG ON THE
SAME SIDE AS INOCULATION
AEFI
3. SEVERE LOCAL REACTION
REDNESS AND/OR SWELLING AT THE SITE
WITH ONE OR MORE OF THE FOLOWWING
1. SWELLING BEYOND JOINT
2. LASTING MORE THAN 3 DAYS OR
3. REQUIRES HOSPITALIZATION
AEFI
CNS ADVERSE EVENTS
1. ACUTE PARALYTIC POLIOMYELITIS
•
WITHIN 4-75 DAYS

RESIDUAL PARALYSIS AFTER 60 DAYS OR
DEATH
AEFI
2. GBS
OCCURING WITHIN 30 DAYS
3. ENCEPHALOPATHY
CASES OCCURING WITHIN 72 HOURS
AFTER VACCINATION
AEFI
4. ENCEPHALITIS
CASES OCCURING WITHIN 72 HOURS
5. MENINGITIS
WITHIN 1- 6 WEEKS
SEIZURES – AFEBRILE
- FEBRILE
AEFI
OTHER ADVERSE EVENTS
1.ALLERGIC REACTION
2.ANAPHYLACTIC SHOCK
3.ARTHRALGIA
4.DISSEMINATED BCG-IT IS
5.HIGH FEVER
AEFI
OTHER ADVERSE EVENTS(CONT)
6. HYPOTENSIVE EPISODE (SHOCK/COLLAPSE)
7. OSTEITIS/OSTEOMYELITIS
8. PERSISTENT SCREAMING
9. SEPSIS (SEVERE GENERALIZED ILLNESS
CONFIRMED BY BLOOD CULTURE)
AEFI
OTHER ADVERSE EVENTS(CONT)
10.TOXIC SHOCK SYNDROME
FEVER, VOMITTING AND WATERY
DIARRHOEA- FEW HOURS AFTER
IMMUNIZATION – OFTEN LEADING TO
DEATH
Examples of types & frequency of
AEFIs (in some common vaccines)
Vaccine
BCG
Hib
Onset
Interval
2-6 months
1-12 months
1-12 months
Rates per
million doses
100 to 1000
1 to 700
2
0-1 hour
0 to 2
1-6 weeks
5-12 days
15-35 days
0-1 hour
5
333
33
1 to 50
Vaccine associated paralytic polio (VAPP)
Persistent (>3 hrs) inconsolable crying
Seizures
Hypotonic, hyporesponsive episode
Anaphylaxis
Encephalopathy
4-30 days
0 -24 hours
0 - 3 days
0-24 hours
0 - 1 hour
0 - 3 days
Post-vaccination encephalitis
Allergic/anaphylaxis
7-21 days
0-1 hour
1.4 to 3.4
1000 to 60000
570
570
20
0 to 1
400 to 4000 (in
infants <6 m)
5 to 20
Reaction
Suppurative lymphadenitis
BCG osteitis
Disseminated BCG-it is
Nil known
Anaphylaxis
Hepatitis B
Guillain-Barrè Syndrome (plasma derived)
Febrile seizures
Thrombocytopaenia
Measles/MMR Anaphylaxis
OPV
DTP
Yellow Fever
AEFI
• Avoiding Programme Errors
–
–
–
–
Use sterile needle & syringe for every injection
Reconstitute only with specific diluent
Discard reconstituted vaccines after six hours
Do not store drugs & other medicines in the same
fridge as the vaccines and diluents
– Train & supervise health workers to ensure safe
injection practices
– Monitor, Investigate and Act when AEFIs occur
AEFI
• Why monitor AEFI?
– No vaccines are 100% safe and without any
risks
– It is important to know the risks and how to
handle such an event when it occurs
– Informing people correctly on AEFI helps keep
public’s confidence in the immunization
programmes
– Monitoring AEFI also helps improve the
quality of service
AEFI
• Steps in AEFI surveillance
– Detection and reporting
– Investigation
– Data analysis
– Corrective and other actions
– Evaluation
AEFI
• Detection and reporting
– Every individual that administers an immunization
injection should know about AEFI
– There should be a national system for detecting and
reporting of AEFI
– At least the following should be included in the
national AEFI monitoring system- “trigger events”
• All injection site abscesses
• All cases of BCG lymphadenitis
• All deaths suspected to be related to immunization
• All hospitalisation suspected to be related to
immunization
AEFI
• Detection and reporting
– The above basic categories act as “trigger”
mechanisms for further course of action
– The national monitoring system should define the
flow of information and mechanisms for taking
actions
– While minor events may be recorded and reported as
a routine activity to be analysed only at periodic
times, sudden, unexplained deaths or large scale
hospitalisation or a cluster of events reported
following immunisation warrants immediate
investigation
AEFI
• Investigation
– AEFI investigation will attempt to
• confirm or propose alternative diagnosis of the reported
event
• identify the specifications of the vaccine incriminated
• examine the operational aspects of the programme
• identify whether it was an isolated event or a cluster of
events and, if a cluster, where the immunization was given
and what vaccines were used
– Preliminary investigation may be carried out by the
local health worker, but serious AEFIs or clusters of
AEFIs should be investigated by special teams from
district or central level
AEFI
• Investigation
– Data on the patient(s); vaccine (lot number, expiry,
manufacturer, lab results if any), storage,
reconstitution practice, diluent used, general disease
information in the area, similar disease episodes in
unimnunized persons in the same locality, etc. should
be collected
– Collect samples of vaccines and diluents used (make
sure vaccine sample collected are kept in the cold
chain)
AEFI: An example of an AEFI
investigation
• Background
– It is reported that following a measles campaign in a
primary school in District X, several children had
convulsions. It was widely rumoured that the measles
injection was responsible for it
• Hypothesis
– that the reported health event (convulsion) was an
AEFI following measles vaccination
• Define the case
– You define your ‘case’ as any child in that primary school who
received measles injection on that particular day and had
convulsions.
AEFI: example contd..
• Case investigation
– Line list all children, with age & sex, who had
received measles injection on that day
– Find those that reported to have had convulsions
– Find out all the details regarding the convulsionsonset time after immunization, manner of convulsion,
recovery following the convulsion, concomitant
medications, fever, any other health problems.
Determine the quality of the vaccine (expiry, storage),
reconstitution, diluent, injection process, etc.
– Take samples of the vaccine vials used for lab testing
– Scrutinise the stock entries, stock balance, etc.
AEFI: example contd..
– One child had an attack of fit half an hour after the
immunization. Following this three other children had
fainting spells in the same class. All recovered
spontaneously although the child who had the first
convulsion took longer to recover. Also, the first child
sustained a minor cut on the forehead from the fall
– Next day, five more children called in sick on grounds
that they had also attacks of fits after the school
AEFI
• Data analysis
– Once the data is collected, it should be analysed as
quickly as possible to determine whether the AEFI is
• Programme related (incorrect dose of vaccine, wrong site,
wrong diluent, improper storage & handling, use of other
medicines as diluent, etc.)
• Vaccine induced AEFI
• Coincidental AEFIs (caused by something other than vaccine
or programme errors)
• Unknown
– Laboratory support
• If patient hospitalised, tests may confirm diagnosis
• Testing vaccines often yield doubtful answers
• Send case investigation report with vaccine for test
AEFI: example contd..
• Data Analysis
– You find that the vaccine used has not expired, was well
maintained in the cold chain, correct diluent was used,
– There was no evidence of contamination, the health workers
always discarded reconstituted vaccine at the end of the
session.
– The medical history showed that the fits which the other children
had were mere fainting spells, lasting only for a few moment,
with spontaneous recovery. No subsequent attacks occurred
– The index child had a true convulsion. No fever or other illnesses
at that time.
AEFI: example contd..
– However, going over the medical history of the child,
the health worker recalled that last year the same
child had an episode of convulsion for which he had
provided treatment. He had advised that the parents
should consult a medical or a neurological expert for
further management. On questioning, it was found
that the parents did not have the time or the money to
do that and it was felt that it would resolve naturally
AEFI
• Corrective and other actions
– Action must not wait for investigation to be completed
– Treat the patient(s) as the first response
– Communicate, inform the public, parents, media
people on the event, actions being taken & next steps
– Once the investigation is completed, publicise the
results
– Take corrective actions, where necessary
– Training of health workers & supervision to prevent
avoidable AEFIs in future
AEFI: example contd..
• Conclusion
– From the available information, and based on
the data analysis, you conclude that event
was not an AEFI, but Coincidental.
– Following this, you will take time to explain to
the parents, teachers and the community
about the event, your investigation and your
final conclusions.
AEFI
• Evaluation
– Like any other surveillance systems, AEFI
surveillance must also be evaluated periodically to
examine its usefulness and to modify it if necessary
– Issues to consider when evaluating a surveillance
system are
• timeliness, completeness, accuracy of the system
• swiftness with which response was effected when
a trigger event was reported
• appropriateness of actions taken
• potential for strengthening of immunization system
AEFI
An ounce of prevention is always better than a
pound of cure. Good training & close
supervision of health workers, coupled with
a functioning surveillance system for
monitoring & reporting are the best
guarantee against the likelihood of an event
occurring at all