adverse events following immunization, aefi
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
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. ENCEPHALOPATHYCASES OCCURING WITHIN 72 HOURS
AFTER VACCINATION
AEFI
4. ENCEPHALITISCASES OCCURING WITHIN 72 HOURS
5. MENINGITISWITHIN 1- 6 WEEKSSEIZURES – AFEBRILE
- FEBRILE
AEFI
OTHER ADVERSE EVENTS
1.ALLERGIC REACTION
2.ANAPHYLACTIC SHOCK
3.ARTHRALGIA
4.DISSEMINATED BCG-IT IS
5.HIGH FEVER
AEFIOTHER 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 SYNDROMEFEVER, VOMITTING AND WATERY DIARRHOEA- FEW HOURS AFTER IMMUNIZATION – OFTEN LEADING TO DEATH
Examples of types & frequency of AEFIs (in some common vaccines)
Vaccine ReactionOnset
IntervalRates per
million dosesSuppurative lymphadenitis 2-6 months 100 to 1000BCG osteitis 1-12 months 1 to 700Disseminated BCG-it is 1-12 months 2
Hib Nil knownAnaphylaxis 0-1 hour 0 to 2
Guillain-Barrè Syndrome (plasma derived) 1-6 weeks 5Febrile seizures 5-12 days 333Thrombocytopaenia 15-35 days 33Anaphylaxis 0-1 hour 1 to 50
OPV Vaccine associated paralytic polio (VAPP) 4-30 days 1.4 to 3.4Persistent (>3 hrs) inconsolable crying 0 -24 hours 1000 to 60000Seizures 0 - 3 days 570Hypotonic, hyporesponsive episode 0-24 hours 570Anaphylaxis 0 - 1 hour 20Encephalopathy 0 - 3 days 0 to 1
Post-vaccination encephalitis 7-21 days400 to 4000 (in infants <6 m)
Allergic/anaphylaxis 0-1 hour 5 to 20Yellow Fever
BCG
Hepatitis B
Measles/MMR
DTP
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 convulsions-
onset 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