Vaccine errors, relating to the way a vaccine is stored, prepared or administered, are a type of adverse event following immunisation (AEFI). Diluent-related errors occur when only the diluent of a vaccine requiring reconstitution is administered, or the incorrect diluent is used to reconstitute a vaccine manufactured in a powered or pellet form.
In general, where only a diluent has been administered, the vaccine should be repeated ideally on the same day or as soon as possible.
The diluent supplied with Infanrix hexa contains the DTPa-hepB-IPV (diphtheria–tetanus-acellular pertussis, hepatitis B, inactivated poliovirus) components as liquid in a syringe. If only the Infanrix hexa diluent is administered, the vaccinee will not receive the Hib (haemophilus influenzae type B) component of the vaccine. In this instance, a dose of ActHIB should be given either at the same time or as soon as the error is realised. This will provide protection against Hib without increasing the chance of vaccine reactions due to the additional dose of other antigens if Infanrix hexa were repeated.
If doses are packaged in multipacks, there is an added complication of identifying which individuals have been impacted by a diluent error. In the case of a discrepancy in diluent–antigen count in a multipack, it is difficult to narrow down which individuals are impacted.
Any adverse event following immunisation (AEFI), including diluent errors, should be reported to the adverse event reporting service in your jurisdiction.
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