Diphtheria Immunity in Australia: Should we be Concerned?

Area of Science:

• Immunology
• Epidemiology
• Public Health

Background:

• Diphtheria immunity is crucial for public health.
• Changes in vaccination schedules can impact population immunity.
• International travel increases the risk of infectious disease spread.

Purpose of the Study:

• To assess diphtheria immunity levels in Australia.
• To evaluate the impact of recent vaccination schedule changes.
• To determine the adequacy of current diphtheria vaccination policies.

Main Methods:

• A national serological survey was conducted in 2007.
• Residual sera (n=1656) were tested for diphtheria antibody levels.
• Enzyme immunoassay was used, with a protective threshold of ≥0.1 IU/mL.

Main Results:

• Approximately 40% of adults aged 30+ are susceptible to diphtheria.
• 59% of 3-year-old children were susceptible following schedule changes.
• Adolescents showed improved diphtheria immunity levels.

Conclusions:

• Australians traveling to endemic areas need up-to-date vaccinations.
• Continued monitoring of population immunity against diphtheria is essential.
• Maintaining adequate immunity levels prevents widespread transmission.