WHO/V&B/AVI Adverse Events Following Immunization, AEFI A brief presentation on the adverse events following immunization, monitoring for AEFIs and taking actions when events occur

WHO/V&B/AVI Adverse Events Following Immunization, AEFI zAdverse events following immunization are events or reactions observed following immunization. Some of these events may be due to the vaccine, some due to error in the administration of the vaccine zThere is no vaccine that is 100% safe & without any risks zSuch events may range from mild side effects to life-threatening, but rare, illnesses

WHO/V&B/AVI AEFI zMild Reactions yMild reactions following immunization are common yThey include pain & swelling at the site of injection, fever, irritability, malaise yThey are self-limiting, hardly requiring even symptomatic treatment yBut it is important to reassure parents about such events so that they know about it

WHO/V&B/AVI AEFI zRare, more severe reactions ySevere reactions are rare ySuch reactions include seizures, thrombocyto-paenia, hypotonic hyporesponsive episodes, persistent inconsolable screaming yIn most cases they are self-limiting and lead to no long-term problems yAnaphylaxis, while potentially fatal, is treatable without any long-term effects

WHO/V&B/AVI Examples of types & frequency of AEFIs (in some common vaccines)

WHO/V&B/AVI AEFI zAvoiding Programme Errors yUse sterile needle & syringe for every injection yReconstitute only with specific diluent yDiscard reconstituted vaccines after six hours yDo not store drugs & other medicines in the same fridge as the vaccines and diluents yTrain & supervise health workers to ensure safe injection practices yMonitor, Investigate and Act when AEFIs occur

WHO/V&B/AVI AEFI zWhy monitor AEFI? yNo vaccines are 100% safe and without any risks yIt is important to know the risks and how to handle such an event when it occurs yInforming people correctly on AEFI helps keep public’s confidence in the immunization programmes yMonitoring AEFI also helps improve the quality of service

WHO/V&B/AVI AEFI zSteps in AEFI surveillance yDetection and reporting yInvestigation yData analysis yCorrective and other actions yEvaluation

WHO/V&B/AVI AEFI zDetection and reporting yEvery individual that administers an immunization injection should know about AEFI yThere should be a national system for detecting and reporting of AEFI yAt least the following should be included in the national AEFI monitoring system- “trigger events” xAll injection site abscesses xAll cases of BCG lymphadenitis xAll deaths suspected to be related to immunization xAll hospitalisation suspected to be related to immunization

WHO/V&B/AVI AEFI zDetection and reporting yThe above basic categories act as “trigger” mechanisms for further course of action yThe national monitoring system should define the flow of information and mechanisms for taking actions yWhile 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

WHO/V&B/AVI AEFI zInvestigation yAEFI investigation will attempt to xconfirm or propose alternative diagnosis of the reported event xidentify the specifications of the vaccine incriminated xexamine the operational aspects of the programme xidentify 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 yPreliminary 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

WHO/V&B/AVI AEFI zInvestigation yData 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 yCollect samples of vaccines and diluents used (make sure vaccine sample collected are kept in the cold chain)

WHO/V&B/AVI AEFI: An example of an AEFI investigation zBackground yIt 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 zHypothesis ythat the reported health event (convulsion) was an AEFI following measles vaccination zDefine the case yYou define your ‘case’ as any child in that primary school who received measles injection on that particular day and had convulsions.

WHO/V&B/AVI AEFI: example contd.. zCase investigation yLine list all children, with age & sex, who had received measles injection on that day yFind those that reported to have had convulsions yFind 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. yTake samples of the vaccine vials used for lab testing yScrutinise the stock entries, stock balance, etc.

WHO/V&B/AVI AEFI: example contd.. yOne 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 yNext day, five more children called in sick on grounds that they had also attacks of fits after the school

WHO/V&B/AVI AEFI zData analysis yOnce the data is collected, it should be analysed as quickly as possible to determine whether the AEFI is xProgramme related (incorrect dose of vaccine, wrong site, wrong diluent, improper storage & handling, use of other medicines as diluent, etc.) xVaccine induced AEFI xCoincidental AEFIs (caused by something other than vaccine or programme errors) xUnknown yLaboratory support xIf patient hospitalised, tests may confirm diagnosis xTesting vaccines often yield doubtful answers xSend case investigation report with vaccine for test

WHO/V&B/AVI AEFI: example contd.. zData Analysis yYou find that the vaccine used has not expired, was well maintained in the cold chain, correct diluent was used, yThere was no evidence of contamination, the health workers always discarded reconstituted vaccine at the end of the session. yThe 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 yThe index child had a true convulsion. No fever or other illnesses at that time.

WHO/V&B/AVI AEFI: example contd.. yHowever, 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

WHO/V&B/AVI AEFI zCorrective and other actions yAction must not wait for investigation to be completed yTreat the patient(s) as the first response yCommunicate, inform the public, parents, media people on the event, actions being taken & next steps yOnce the investigation is completed, publicise the results yTake corrective actions, where necessary yTraining of health workers & supervision to prevent avoidable AEFIs in future

WHO/V&B/AVI AEFI: example contd.. zConclusion yFrom the available information, and based on the data analysis, you conclude that event was not an AEFI, but Coincidental. yFollowing this, you will take time to explain to the parents, teachers and the community about the event, your investigation and your final conclusions.

WHO/V&B/AVI AEFI zEvaluation yLike any other surveillance systems, AEFI surveillance must also be evaluated periodically to examine its usefulness and to modify it if necessary yIssues to consider when evaluating a surveillance system are xtimeliness, completeness, accuracy of the system xswiftness with which response was effected when a trigger event was reported xappropriateness of actions taken xpotential for strengthening of immunization system

WHO/V&B/AVI 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