Vaccination and AEFIs

This segment includes additional information on:

  • 1Adverse events following immunization (AEFIs),
  • 2Preparing for unavoidable AEFIs.

Vaccination and AEFIs

Once vaccine programmes have been successful and fears of diseases have declined, greater public attention may be focused on AEFIs. Poor management of AEFIs can damage public confidence in vaccination. As a result, vaccine rates drop and preventable diseases re-emerge where once they had almost disappeared.

Media coverage, particularly via the Internet, can quickly fuel public fears about the safety of vaccines. Government and responsible agencies must respond immediately and appropriately with accurate facts to prevent a loss of confidence in vaccination due to misinformation about an adverse event.

As demonstrated in this case study, the case of the student death shortly after vaccination never reached crisis level due to the immediate and appropriate management of the situation by the UK DH.

Cervarix: not the new MMR

The UK press may have learnt lessons from the MMR furore, though it hasn’t stopped some papers from sensationalist stories about the HPV vaccines

– British Medical Journal reports (10 Oct 2009)

What can you do about AEFIs?

This AEFI section was taken largely from the WHO/PAHO document entitled "Immu­ni­za­tion Safety: How to address events allegedly attributable to vaccination or im­mu­ni­za­ti­on?"

There are five types of AEFIs:

AEFIs that can be avoided or mitigated:

Immunization error-related reaction

An AEFI that is caused by inappropriate vaccine handling, prescribing or administration and thus by its nature is preventable.

Immunization error-related reactions can be prevented by providing adequate training and supplies.

Immunization anxiety-related reaction

An AEFI arising from anxiety about the immunization.

Clear explanations about immunization and calm, confident delivery can decrease the level of anxiety about the injections, and thus reduce the likelihood of an occurrence.

AEFIs that are unavoidable:

Vaccine 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.

Vaccine 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.

Coincidental event

An AEFI that is caused by something other than the vaccine product, immunization error or immunization anxiety.

Health authorities can take certain steps in advance:

  • Anticipate. Do not wait until a crisis develops. Prepare for the unavoidable.
    This includes knowing the baseline evidence of possible serious adverse events.
  • Train vaccination personnel at all levels to respond appropriately.
  • Confirm all the facts before making any public statements.
  • Prepare a plan to react to a crisis when it occurs.
    This includes immediate reporting of AEFIs to the national agency responsible for pharmacovigilance.

See Resources section for additional information on how to prepare for AEFIs.

Background rates

Vaccination programmes specifically for adolescents and young adults are relatively new, and there is limited data on the baseline incidence of many diseases in these populations. Because HPV vaccination requires three vaccine doses over a six-month period, virtually anything that occurs during that year in the adolescent’s life will be temporally associated with an injection of the vaccine.

It is important to have an understanding of population-based incidence/prevalence rates in the pre-HPV vaccine era in order to allow a rapid distinction between real vaccine-induced adverse events and alleged concerns.

To understand background rates, researchers reviewed emergency consultations, hospitalizations and outpatient visits among female adolescents and the young adult population during 2005.80