We used the 2002 national serosurvey to evaluate a primary care-based young adult vaccination campaign, measure the reproductive number (R) and, together with vaccination coverage estimates, predict R until 2012. The campaign had no impact on immunity in young adults. R was estimated to be 0.69 and predicted to stay well below the epidemic threshold of 1 until at least 2012, indicating that Australia should remain free of endemic measles in the medium term. To maintain elimination in the longer term, the timeliness and coverage of childhood vaccinations must improve and innovative strategies will be required to improve measles immunity among young adults. This experience is likely to apply to developed countries that have achieved or are approaching measles elimination.