Xinting Lu*, Helen E. Quinn, Rob I. Menzies, Linda Hueston, Lyn Gilbert and Peter B. McIntyre Pages 1 - 7 ( 7 )
We report the results of the 2007 national serological survey of immunity to diphtheria in Australia to assess the impact of recent schedule changes on diphtheria immunity, and the adequacy of current policy in the context of increased international travel of people and pathogens. Residual sera (n =1656) collected opportunistically from Australian laboratories in 2007 were tested for diphtheria antibody levels using an enzyme immunoassay, with the protective threshold defined as ≥0.1 IU/mL. About 40% of adults aged ≥30 years are susceptible to diphtheria; following the removal of the 18-month booster and its replacement with a dose in adolescence offered through school-based dTpa vaccination program, 59% of children aged 3 years were susceptible to diphtheria, whilst adolescents demonstrated improved immunity. There is no apparent boosting of diphtheria immunity from meningococcal group C conjugate (MCC) or seven-valent pneumococcal conjugate (7vPCV) vaccines in relevant age groups. Australians who travel to diphtheriaendemic areas should be up-to-date with their vaccinations. Close monitoring of population immunity levels against diphtheria remains important to ensure that immunity does not decline to a level where wide-spread transmission would be possible.
Diphtheria, seroepidemiology study, adult vaccination, Australia
School of Public Health, University of Sydney, National Centre for Immunisation Research & Surveillance (NCIRS), The Children's Hospital at Westmead, School of Public Health and Community Medicine, UNSW , Centre for Infectious Diseases and Microbiology – Public Health, Institute for Clinical Pathology and Medical Research (ICPMR), Westmead, Sydney, Marie Bashir Institute for Emerging Infections and Biosecurity, University of Sydney, National Centre for Immunisation Research & Surveillance (NCIRS), The Children's Hospital at Westmead