Adverse Events Following Immunization - PowerPoint Presentation

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Adverse Events Following Immunization(AEFI)

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Adverse Events Following Immunization (AEFI)

The goal of immunization is to protect individuals from specific disease; but may lead to adverse events that require careful monitoring.

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Definition of AEFI

It is a medical incident that takes place

after an immunization, causes concern

and is believed to be caused by the vaccine.

It may be any unfavorable symptoms,

disease sings or abnormal laboratory finding

.

Can be mild or severe.

Can occur in clusters or isolated.

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Pharmacovigilance

Is the science and activities done for detection,

assessment, understanding and preventions of adverse

events following immunizations and any other vaccine

related issues

.

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Impact of AEFI on Immunization

Programm

Can extend from local to national level leading to short or long-lasting consequences.

Can affect public trust in immunization services.

Decrease in routine & supplementary immunization coverage.

Resurgence of vaccine preventable diseases & unnecessary deaths.

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Serious AEFI

Life threatening

Death

Hospitalization

Significant disability

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signal & cluster

A cluster

of AEFIs : two or more cases of the same adverse event

related in time, place or vaccine administered

. Or

aggregation of relatively uncommon events in place and/or time in frequency to be grater than expected by chance

.

A

signal

defined as:

possible causal relationship between an adverse event and a vaccine

, the relationship being unknown or incompletely documented previously.

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Classification of AEFI

Vaccine Reaction.

Program Error.

Immunization anxiety related reaction

Co incidental causes

Unknown.

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Cont.

Vaccine quality defect related reaction :

AEFI related to quality defects of the vaccine product e.g. failure by the manufacturer to completely inactivate a

lot

or batch of inactivated polio vaccine leads to cases of paralytic polio.

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Cont.Usually present in clusters (routine or campaign vaccination)

Easy to be identified if following a correct way of investigations

Vaccine specimens, lots and all other information's are needed

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Cont.

Suspending vaccination is a rare action usually

Manufacturer reports batch problem

e.g.,

- Bell’s Palsy with inactivated nasal flu vaccine

Intussusceptions with Rota shield.

May need to suspend vaccination

temporarily

pending investigation outcome

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common minor vaccine reaction

Irritability, malaise and

systemic symptoms

Fever >38oC

Local reaction (pain,

swelling, redness)

Vaccine

_

90

– 95 %

BCG

_

2

- 10 %

5 – 15 %

Hib

_

1 – 6 %

adults ~15%

children ~ 5%

Hepatitis B

5% (rash)

5 – 15 %

10%

Measles / MMR /MR

< 1 %

< 1 %

--

Oral poliomyelitis (OPV)

25%

~

10 %

~

10

Tetanus / DT / Td

up to 55%

up to 50%

up to 50%

Pertussis (whole cell)

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Expected rate of serious vaccine reaction

Expected per million doses

Onset interval

Reaction

vaccine

100

- 1000

2-6 months

Supurative

lymphadenitis

BCG

1 - 700

1-12 months

BCG Ostitis

2

1-12 months

Disseminated BCG

1 – 2

0-1 hour

Anaphylaxis

Hep

b

5

1

– 6 weeks

GBS

333

6-12 days

Febrile convulsion

Measles

1 – 50

0-1 hour

Anaphylaxis

33

15-35 days

Thrombocytopenia

1

6-12 days

Encephalopathy

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Expected rate of serious vaccine reaction

Expected per million doses

Onset interval

Reaction

vaccine

1000 - 60000

0-24 hours

Persistent (> 3 hours) inconsolable screaming

Pertussis

(DTP– whole cell)

20

0-1 hour

Anaphylaxis

30

- 990

0-24 hours

Hypotonic, hypo responsive episode

80 – 570

6-12 days

Seizures

5 – 10

2-28 days

Brachial neuritis

TT

1 – 6

0-1 hour

Anaphylaxis

1.4-3.4

4-30 days

VAPP

Polio

19

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Program error

Usually related to handling or administration of the vaccine e.g.:

Injection in wrong place

Sterilization issues by handling needles incorrectly

Using incorrect diluents

Drugs substituted for vaccine or diluents

Storage and transport problems

Ignoring

contraindications

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Programme error

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Cluster AEFI Cases

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Cluster AEFI cases

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Coincidental Events

Something

not

related to program error or to individual reaction to vaccine

It is medical event that would have occurred even if the individual had not been immunized

Strong evidence for Coincidental Event is that the same event has been reported in people who have not been immunized

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Immunization anxiety reaction

- This reaction is unrelated to the content of the vaccine

- arising from anxiety about the act of the vaccination itself

eg

.

Vaso

vagal syncope in adolescent following vaccination

Usually occur during mass vaccinations

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BCG

Koch’s phenomenon: Accelerated reaction (10 days-Diagnostic tool)

Complications: Erythema nodosum, abscess, ulceration, local lymphadenopathy and generalized T.B

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Unknown/ Unclassified Unknown category when after intensified correct investigations no cause identified.

This an area for research and reinvestigation which might reclassify latter to one of the categories above .

Can be due incomplete data

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What/when to investigate

Serious

AEFIs.

Clusters

and events

above

the expected rate

AEFIs possibly caused by

program error

(e.g.

bacterial abscess, severe local reaction, high fever or sepsis, BCG lymphadenitis, toxic shock syndrome)

−

Significant events of unexplained cause

occurring within 30 days after vaccination

Events causing

significant parental or community

concern

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AEFI surveillance tools

AEFI field guide lines

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Objectives of AEFI Surveillance System

Detect, correct, and prevent

program 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.

Estimate rates of occurrence

on AEFI in the local population, compared with trial and international data (particularly for new vaccines being introduced)

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AEFI Surveillance

System

Types of reports

:-

Urgent notification of serious cases.

Weekly report from sentinel sites integrated with measles and AFP.

monthly aggregated data

from states.

Investigation form for the cases should be investigated.

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Immediate notification form

AEFI surveillance tools

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AEFI investigation form

AEFI surveillance tools

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Monthly report from vaccination site to locality

AEFI surveillance tools

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General rules

Treat

the patient.

Communicates

with patients/parents, health workers EPI and community.

Analyze

data.

Do

corrective measures.

Summarize

and report findings to: National

stakeholders

International

Causality

assessment

Take

action

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Investigation Key Points

Understand the safety profile of commonly used vaccines & background rates of AEFI.

Safety profile of vaccines depends in some cases on risk factors of person being vaccinated.

Understand possible mechanisms, treatment and prevention of vaccine reactions.

Verify reported event(s) early in investigation.

Establish that

onset

occurred

after

vaccination

.

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Immunization errors leading to adverse events

Adverse event

immunization

error

(e.g. local suppuration at injection site, abscess, cellulitis, systemic infection, sepsis, toxic shock syndrome, transmission of blood borne disease (HIV, hepatitis B or

hepatitis C)

Non-sterile injection

reuse of disposable syringe or needle

· improperly sterilized syringe or needle

· contaminated vaccine or diluents

· reuse of reconstituted vaccine at subsequent session

Local reaction or abscess from inadequate shaking.

Effect of drug (e.g. muscle relaxant, insulin).

Vaccine prepared incorrectly

vaccine reconstituted with incorrect diluent

· drugs substituted for vaccine or diluent

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Immunization errors

AEFI Surveillance 2012

Adverse event

immunization

error

Local reaction or injection site abscess

Local reaction or injection site abscess

Sciatic nerve injure

Immunization injected in wrong site

:

· subcutaneous instead of intradermal for BCG

· too superficial for toxoid vaccine (penta, TT)

· buttocks.

Increased local reaction from frozen vaccine (and ineffective vaccine).

Vaccine transported/stored incorrectly

Avoidable severe vaccine reaction

Contraindications ignored.

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