diphtheria, tetanus and pertussis vaccine: clinical use

Prescribing considerations

• Confirm primary immunisation, vaccination history and previous adverse reactions.
• Postpone during acute severe febrile illness; minor infection alone is not a contraindication.
• Assess bleeding risk, immunosuppression, neurological history, syncope risk and latex sensitivity.
• Ensure facilities and trained staff are available to recognise and treat anaphylaxis.
• Use separate sites for concomitant parenteral vaccines and record the product and batch.

Contraindications and cautions

• Hypersensitivity to relevant vaccines, an excipient, or residual formaldehyde or glutaraldehyde.
• Encephalopathy of unknown origin following a previous pertussis-containing vaccine.
• Progressive neurological disorder, uncontrolled epilepsy or progressive encephalopathy until treatment is established and the condition stabilised.

Monitoring

• Observe for immediate hypersensitivity, syncope and injection-related complications.
• Explain expected reactions and symptoms requiring urgent assessment.
• Consider reduced immunogenicity with immunodeficiency or immunosuppressive treatment.
• Record the brand and batch for traceability.

Clinical pharmacology

An adsorbed reduced-antigen Tdap vaccine containing diphtheria and tetanus toxoids and four acellular pertussis antigens. It induces active antibody responses; maternal antibodies provide temporary passive infant protection.

Formulation and product differences

• ADACEL does not contain poliovirus antigen; some alternative pertussis-containing products also include inactivated polio vaccine.
• It is a cloudy white suspension in a single-use pre-filled syringe containing phenoxyethanol and water for injections, with possible traces of formaldehyde and glutaraldehyde.
• Some syringe tip caps contain a natural-rubber latex derivative; rigid tip-cap presentations use synthetic materials.
• It is adsorbed on aluminium phosphate and must be shaken to a uniform suspension before use.