Diphtheria vaccination

• Diphtheria toxoid vaccine, is prepared from inactivated toxin adsorbed onto a mineral carrier.
• Diphtheria vaccines are produced in two strengths according to the diphtheria toxoid content:
  • vaccines containing the higher dose of diphtheria toxoid (abbreviated to ‘D’) contain not less than 30IU
    • use to achieve satisfactory primary immunisation of children under ten years of age.
  • vaccines containing the lower dose of diphtheria toxoid (abbreviated to ‘d’) contain approximately 2IU.
    • should be used for primary immunisation in individuals aged ten years or over, where they provide a satisfactory immune response and the risk of reactions is minimized
    • this precautionary advice is particularly pertinent when the early immunisation history and possibility of past exposure are uncertain
    • low-dose preparations are also recommended for boosting
• monovalent diphtheria vaccine is not available. It is usually administered as part of combined products:
  • diphtheria/tetanus/acellular pertussis/inactivated polio vaccine/Haemophilus influenzae type b/Hepatitis B (DTaP/IPV/Hib/Hep B)
  • diphtheria/tetanus/acellular pertussis/inactivated polio vaccine (dTaP/IPV or DTaP/IPV)
  • tetanus/diphtheria/inactivated polio vaccine (Td/IPV).
• for most circumstances, a total of five doses of vaccine at the appropriate intervals are considered to give satisfactory long-term protection
  • primary immunisation
    • infants and children under ten years of age
      • consists of three doses of a D-containing product
      • DTaP/IPV/Hib is recommended to be given at two three and four months of age but can be given at any stage from two months to ten years of age.
      • if the primary course is interrupted it should be resumed but not repeated, allowing an interval of one month between the remaining doses
    • children aged ten years or over, and adults
      • consists of three doses of a d-containing product with an interval of one month between each dose
      • Td/IPV is recommended for all individuals aged ten years or over
      • if the primary course is interrupted it should be resumed but not repeated, allowing an interval of one month between the remaining doses
  • reinforcing immunisation
    • the first booster
      • children under ten years
        • the first booster of a diphtheria-containing vaccine should ideally be given three years after completion of the primary course normally when the child is between three-and-a-half and five years of age
        • when primary vaccination has been delayed, this first booster dose may be given at the scheduled visit – provided it is one year since the third primary dose
        • DTaP/ IPV or dTaP/IPV should be used in this age group (Td/IPV should not be used routinely for this purpose in this age group)
      • children aged ten years or over
        • should receive the first diphtheria booster combined with tetanus and polio vaccines (Td/IPV).
    • the second booster dose
      • Td/IPV should ideally be given to all individuals ten years after the first booster dose.
      • if the previous doses have been delayed, the second booster should be given at the school session or scheduled appointment – provided a minimum of five years have elapsed between the first and second boosters

In travellers where tetanus, diphtheria or polio protection is required and the final dose of the relevant antigen was received more than ten years ago, Td/IPV should be given (1).

Note that (1):

• Td/IPV vaccine should be used where protection is required against tetanus, or diphtheria or polio in order to provide comprehensive long-term protection against all three diseases

Reference:

• (1) Immunisation Against Infectious Disease - "The Green Book". Chapter 15 Diphtheria (April 2019)