preparing for aefi investigations

Investigation of AEFIs Module D | | 1

Preparing for AEFI investigations

Establish standards & procedures

*

Designate and train

staff

Establish investigation

team

Identify spokesperson

for public communication

*Standards: Case definitions, reporting forms and investigation procedures. *Procedures: Guidelines, criteria, roles and responsibilities, timelines, systems


Before initiating investigation

• Establish that onset occurred after vaccination.

Verify the accuracy of the event

• The safety profile of concerned vaccines & background rates of AEFI.

• Possible mechanisms, treatment and prevention of additional cases.

Review

Consider the risk factors of vaccinated person


Be prepared for…

Visiting the immunization site, vaccine storage points, residence and locality of the patient (if relevant) and the treatment centre(s).

Interviewing the patient, parents or guardian, the treating health staff and the staff who provided immunization and collect relevant information.


Step 1: Confirm information in report

Obtain patient’s medical file (or other clinical record)

Check details about patient and event; confirm information in the investigation form. • Particularly verify the time sequence of vaccination and the event

Obtain any details missing from AEFI Reporting / Investigation Form.

Identify any other cases that need to be included in the investigation.


Step 2 a: Investigate and collect data about the PATIENT

• Immunization history

• Previous medical history, including prior history of similar reaction or other allergies

• Family history of similar events.

Review Patient Records


Step 2b: Investigate and collect data about the EVENT

History of the event in chronological order

Detailed clinical description including sequence of clinical manifestations and the response to treatment

Relevant laboratory tests and other investigations (eg X- ray, ECG etc) performed and results

Details of treatment and outcome


Step 2c : Investigate and collect data about the SUSPECTED VACCINE(S)

Shipping Conditions from manufacturer to the last major storage point

Storage point conditions (refrigerator), documentation and shipment to vaccination site

Vaccine handling at the site - cold boxes, condition of ice packs and duration of exposure to ambient temperature

The condition of vaccine vial monitor.


Step 2 d: Investigate and collect data about OTHER PERSONS

If others in the community had similar illness; use a case definition (module G), categorize cases and determine the vaccination status of the affected

• If possible, try to obtain details of beneficiaries who

received the vaccine from • the same distribution point • the same centre • the same vial


Step 3a: Assess the immunization service by making enquiries

• Dosage, person, site and technique • Vaccine storage distribution, and disposal • Reconstitution procedure • Time between reconstituting and

administration • Use and sterilization of reusable (not

recommended) syringes and needles • Number/ type of immunizations and other

medications (eg Vit A) at the site on the day • Staff training

Ask

?


Step 3b: Assess the service by observing it in action

• How vaccines are placed in the cold chain • If other drugs are stored with

vaccines/diluents • Whether any vials have lost their label • Batch numbers and expiry dates • If the opened vials look contaminated • Directly the immunization procedures

(reconstitution, drawing up vaccine, injection technique, safety of needles and syringes; disposal of opened vials) - if possible

See

Sense the ambience of the immunization session (including the interaction of the health worker with beneficiaries) and try to assess if it is child friendly


Step 4a: Specimen collection: Patient • Guided by clinical presentation

Event Specimen from the patient

Severe local reaction Blood Abscess Swab, Blood Lymphadenitis Blood CNS symptoms with no paralysis

Cerebrospinal fluid, blood

CNS symptoms with paralysis Stool Anaphylaxis Blood Toxic shock syndrome Blood Death Post mortem tissue specimen

• An autopsy within 72 hours provides the best information

• If autopsy is not possible, try to obtain biological specimens from the dead body for lab tests

• It is essential to carry out a focussed verbal autopsy.

Death


Step 4b: Specimen collection: Vaccine

• Testing vaccine quality RARELY needed • May be part of regulatory protocols

Evaluating the vaccine

Only on clear suspicion, NOT as routine, and never before a working hypothesis has been formulated

• Sterility (vaccine and/or injection equipment) • Chemical composition ("analytical")

• preservatives, adjuvant level etc. (e.g., aluminium content) • abnormal components (e.g., suspect drug instead of vaccine)

• Biological tests (abnormal toxicity)

Following tests may confirm/rule out suspected hypothesis


Step 4b: Vaccine testing

Use local expertise (e.g., NCL) to assist with testing

Check batch release documentation

Check if manufacturer’s protocol within international standards*

• If possible, collect vial of residual vaccine. • Retain few unopened vaccine and diluent vials from the

same site • maintain at appropriate storage condition until decision on testing

Ensure adequate samples collected from the implicated facility

*e.g., WHO TRS guidelines, European Pharmacopoeia)


Step 4b: Laboratory testing by working hypothesis

Working hypothesis Immunization error is

suspected Specimens to send Laboratory test

Vaccine transportation or storage Vaccine vial Composition

(for frozen vaccine)

Reconstitution error Vaccine vial and/or diluent

Sterility or composition (chemical)

Non-sterile injection Needle, syringe, vaccine vial and

diluent Sterility

Vaccine physical condition problem Vaccine vial Composition


Preparing the dossier

• Case report form • Case Investigation Form, • Copies of all relevant documents

and photographs • Completed Clinical Case record, • Lab reports • Autopsy report, • Details of community investigations

Contents of the

dossier


Investigation: Taking action

Suspending vaccination is RARELY necessary e.g. • Manufacturer reports batch problem • New vaccine found to have caused serious

adverse event e.g., • Bell’s Palsy with inactivated nasal flu vaccine • Intussusception with RotashieldTM

May need to suspend vaccination temporarily pending investigation outcome • Serious immunization error (e.g. TSS

after measles vaccine) retraining staff, not a vaccine recall


Treat patient

Take appropriate corrective actions based on available data/information and AEFI causality classification*

Early communication on the cause to affected and concerned patient/public

Report findings to national and international partners (WHO, UNICEF, manufacturer)

Collect additional information for causality assessment if requested

Investigation: Taking action - General Principles

* Details in Module I

preparing for aefi investigations

Documents