Cost effectiveness of prevaccination screening of health care workers for immunity to measles, rubella and mumps.

OBJECTIVES: To determine the value of infection and vaccination histories as predictors of immunity to measles, rubella and mumps, and to compare the costs of various screening strategies with the cost of universal vaccination of health care workers.

SETTING: Staff employed by a Sydney children's hospital.

METHODS: Histories of measles, rubella and mumps infection or vaccination were compared with the results of serological testing to determine which historical statements had high positive predictive values (PPV) for immunity. Using this, we devised three prevaccination screening strategies and compared their costs with the cost of universal staff vaccination.

RESULTS: Of 235 participants, 98.3% were serologically immune to measles, 96.6% to rubella and 83.0% to mumps. Historical statements indicating immunity with a PPV of more than 95% were histories of measles or of rubella vaccination, and personal recollection of mumps infection. Strategies using historical screening were cheaper than universal vaccination, which in turn was cheaper than using serological screening alone.

CONCLUSIONS: Among health care workers at occupational risk of measles, rubella and mumps, the need for vaccination can be reduced by combining historical and serological screening. Where screening is felt to impose an administrative burden, a universal vaccination strategy costs 30%-50% more than strategies which use historical screening.