The effectiveness of prophylaxis for measles contacts in NSW.

OBJECTIVES As international estimates of the effectiveness of post-exposure prophylaxis of measles vary, we sought to determine the effectiveness of post-exposure prophylaxis with either vaccine or immunoglobulin in susceptible persons with known measles contact. METHODS Data were obtained on all cases of measles notified in NSW between 1 March and 31 May 2006 and their contacts. The effectiveness of prophylaxis was calculated using the cohort method. RESULTS During March to May 2006, 57 cases of measles were notified and 1760 measles contacts were identified, of which 553 were classified as susceptible. The calculated effectiveness of post-exposure prophylaxis with vaccine or immunoglobulin in preventing measles was 83.3% (95% CI: 27-96%). CONCLUSION Post-exposure immunisation remains an effective tool for preventing secondary cases of measles.