adverse events following immunization (aefis)

AEFIADVERSE EVENT FOLLOWING

IMMUNIZATION

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Contents of this lecture

• Definition of AEFI

• Classification of AEFIs

• Serious AEFI

• Examples of AEFIs

• Reporting and Surveillance of AEFIs

Definition

• An AEFI is any untoward medical occurrence which follows immunization and which does not necessarily have a causal relationship with the usage of the vaccine. The adverse event may be any unfavorable or unintended sign, abnormal laboratory finding, symptom or disease.

AEFI Frequency Terminology

Very common* > 1/10 > 10%

Common (frequent)

> 1/100 and < 1/10 > 1% and < 10%

Uncommon (infrequent)

> 1/1,000 and < 1/100 > 0.1% and < 1 %

Rare> 1/10,000 and < 1/1,000

> 0.01% and < 0.1%

Very rare* < 1/10,000 < 0.01%

* Optional categories

Classification of AEFIs

Module B | May 2013 | 6AEFI Basic concepts

1Vaccine product-related

reaction

An AEFI that is caused or

precipitated by a vaccine due

to one or more of the inherent properties of the vaccine

product.

2Vaccine quality defect-related

reaction

An AEFI that is caused or

precipitated by a vaccine that is due to one

or more quality defects of the vaccine

product including its

administration device as

provided by the

manufacturer.

3Immunization error-related

reaction

An AEFI that is caused by

Inappropriate vaccine

handling, prescribing or

administration.

4Immunization

anxiety-related reaction

An AEFI arising from anxiety

about the immunization.

5

Coincidental event

An AEFI that is caused by something

other than the vaccine product,

immunization error or

immunization anxiety

CIOMS/ WHO cause specific definition of AEFIs

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1Vaccine product-related

reaction

EXAMPLE Extensive

limb swelling following DTP vaccination.

2Vaccine quality defect-related

reaction

EXAMPLE

Failure by the manufacturer to completely

inactivate a lot of

inactivated polio vaccine leads to cases

of paralytic polio.

3Immunization error-related

reaction

EXAMPLE

Transmission of infection by contaminated

multidosevial.

4Immunization

anxiety-related reaction

EXAMPLE

Vasovagal syncope in an

adolescent following

vaccination.

5

Coincidental event

EXAMPLE A fever after vaccination (temporal

association) and malarial

parasite isolated from

blood.

CIOMS/ WHO cause specific definition of AEFIs

Vaccine Reactions

Two types of vaccine reactions-Minor and Severe

Two types of vaccine reactions-Minor and Severe

Two types of vaccine reactions-Minor and Severe

Antigen[Live, Killed,

Purified, Inactivated

toxin]

Stabilizers(help the vaccine maintain its effectiveness during storage)

[MgCl2, MgSO4]

Adjuvants(improve the immune response to

vaccine antigens, most often in killed vaccine)

[Aluminium salts]

Antibiotics(to prevent bacterial

contamination of the tissue culture cells in which the viruses

are grown)

[Neomycin]

Preservatives(added to multidose vaccines to

prevent bacterial and fungal growth)

[Thiomersal, Formaldehyde]

AEFI Reporting and Surveillance

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Vaccine safety terminology: Serious adverse event/reaction

• Death

• Hospitalization or prolongation of existing hospitalization (e.g., encephalopathy, seizures, aseptic meningitis)

• Persistent or significant disability or incapacity (e.g., paralysis)

• Congenital anomaly/birth defect

• Life-threatening

Serious AEFI

Source: report of CIOMS/WHO Working Group on Vaccine Pharmacovigilance, 2012

‘Serious’ is not synonymous with ‘severe’ (i.e., intensity or severity of the event)

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"A cluster of AEFIs is two or more cases of the same adverse event related in time, place or vaccine administered".*

* WHO Aide Memoire: AEFI Investigation, 2004

** Last, John M. 2001. A Dictionary of Epidemiology, 4th ed,

R. A. Spasoff, S.S. Harris and M.C. Thuriaux eds. Oxford: Oxford University Press

Vaccine safety terminology: Cluster

Aggregation of relatively

uncommon events or diseases

in space and/or time in

frequency that are believed or

perceived to be greater than

could be expected by chance.**

Module B | May 2013 | 18AEFI Basic concepts

Vaccine safety terminology: AEFIs needing special attention

• e.g. bacterial abscess, severe local reaction, high fever or sepsis, BCG lymphadenitis, toxic shock syndrome, clusters of AEFIs)

If immunization error is suspected

Significant events of unexplained cause occurring within 30 days after a vaccination

Events causing parental or community concern

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Serious AEFI Potential immunization

error

Cluster

Parental concern

Community concern

Unexpected relationship

with vaccination

Unexpected frequency

AEFI Case selection for Reporting*

Reporter should NOT assess

causality

* Events to be reported according to context - Routine surveillance, new vaccine, mass campaign etc

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AEFI RECORDING ANDREPORTING IN INDIA

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CASES TO BE REPORTED

Serious AEFI

Severe AEFI

Minor AEFI

Which AEFIs should be notified to health system?

Any AEFI that is of concern to the parents or to the health care worker should be notified

In particular, health workers should notify:

Serious AEFIs (death, hospitalization, cluster, disability)

Signals and events associated with a newly introduced vaccine.

AEFIs that may have been caused by an immunization error.

Significant events of unexplained cause occurring within 30 days after a vaccination.

Events causing significant parental or community concern.

Swelling, redness, soreness at the injection site IF it lasts for more than 3 days or swelling extends beyond nearest joint.

Reporting formats and channels

CASE REPORTING FORM (CRF)CASE INVESTIGATION FORM(CIF)

- Preliminary- Final

Serious/severe AEFIs

Case Reporting Form- Routing, timeline, actions

Medical Officer

Pvt Practitioner

District

Immunization

Officer

State

Immunization

Officer

DC ImmunizationDivisionMoHFW,

Govt.of India

• Confirm AEFI

• Complete Case Reporting Form

• Assign EPID number, complete additional details

• Dist level planning meeting on investigation

• Send copy of CRF to local drug inspector, team conducting autopsy & other stakeholders

• Initiate collection of vaccine, logistic samples, CSF, Serum (or biological products), if indicated

• Start collecting data for completing CIF

• Inform if necessary State/regional AEFI committee State Drug Controller

• If necessary, convene State AEFI Committee Meeting to plan course of action

State

District

National

24 Hours

24 Hours

Site Immediate

Health Worker

Case Investigation Form- Routing, timeline, actions

District

Immunization

Officer

Preliminary

CIF

State

Immunization

Officer

DC Immunization

Division MoHFW,

Govt.of India

Inform DCG(I) & senior officers in the MoH&FW

Inform the Vaccine manufacturers and review GMP

Final

CIF

10

day

s o

f N

oti

fica

tio

n• Convene district AEFI committee meeting and finalize

action

• If indicated and recommended, ship specimens to

appropriate labs

• Site (s) visit and investigation

• Collect additional details

Vaccine/logistic distribution and utilization

Other AEFI in the area

Other details such as pre-existing health, medical and environmental condition

• Inform state AEFI committee & State Drug Controller

• Request for additional information if necessary

• Do a causality assessment within 100 days of notification

70

days o

f No

tification

State

National

District

Serious AEFI Cases (formats and timelines)

Type of Report Responsible Time line

CASE REPORTING FORM(CRF)

MO24 hours of notification

DIO48 hours of notification

CASE I

NVESTIG

ATIO

N

FO

RM

(CIF

) Preliminary DIO10 days of notification

Final AEFI investigation team 70 days of notification

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