Seroprotection to vaccine-preventable diseases among workers at a Victorian tertiary hospital.

Objective: To determine seroprotection for the vaccine-preventable diseases (VPDs) measles, mumps, rubella, varicella and hepatitis B among new employees seen at a Victorian tertiary hospital staff clinic.

Methods: Employees who presented to the staff clinic for immunisation assessment between 1 January 2012 and 31 December 2013 were included. Demographic data, self-reported disease history and previous vaccination status were reviewed retrospectively to determine impact on serological results.

Results: A total of 1,901 new employees were included, 83% of whom were at risk of direct contact with blood or body substances. Overall, the proportion of workers seropositive to measles was 88%, mumps 90%, rubella 78%, varicella 93% and hepatitis B 80%. Staff born before 1966 were more likely to have positive measles or mumps serology but negative rubella or hepatitis B serology (p<0.05 for each). Staff who self-reported measles (99% vs. 93%, p=0.03) or varicella infection (98% vs. 92%, p<0.001) were more likely to be seropositive, but those reporting previous vaccination to measles, mumps or rubella were no more likely to be seropositive.

Conclusions And Implications: This study demonstrated levels of seropositivity of 78-93% for the five VPDs. Despite recognised limitations of serological testing, 10-20% of new employees to a healthcare institution lacking seroprotection represents a potentially unacceptable risk of nosocomial transmission of these VPDs. Our findings support ongoing serological testing of new healthcare staff at risk of direct contact with blood or body substances.