Adverse Events Following Immunization, AEFI

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 • Adverse 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 • There is no vaccine that is 100% safe & without any risks • Such events may range from mild side effects to life-threatening, but rare, illnesses WHO/V&B/AVI

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

AEFI • Rare, more severe reactions • Severe reactions are rare • Such reactions include seizures, thrombocyto-paenia, hypotonic hyporesponsive episodes, persistent inconsolable screaming • In most cases they are self-limiting and lead to no long-term problems • Anaphylaxis, 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 • 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 WHO/V&B/AVI

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 WHO/V&B/AVI

AEFI • Steps in AEFI surveillance • Detection and reporting • Investigation • Data analysis • Corrective and other actions • Evaluation WHO/V&B/AVI

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 WHO/V&B/AVI

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 WHO/V&B/AVI

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 WHO/V&B/AVI

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) WHO/V&B/AVI

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. WHO/V&B/AVI

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. WHO/V&B/AVI

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 WHO/V&B/AVI

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 WHO/V&B/AVI

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. WHO/V&B/AVI

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 WHO/V&B/AVI

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 WHO/V&B/AVI

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. WHO/V&B/AVI

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 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 Thank You WHO/V&B/AVI

Adverse Events Following Immunization, AEFI