High rubella seronegativity in daycare educators.

BACKGROUND

Congenital rubella syndrome, which is associated with severe malformations, can result from infants exposed in utero to maternal rubella infection. Health care workers and school-based educators are targeted for immunization, but evidence is scarce on rubella seronegativity in daycare centre educators who appear to be a high-risk occupational group. The purpose of the study was to generate new evidence on the magnitude of rubella seronegativity and associated risk factors in daycare centre educators.

METHODS

Sera and questionnaires were collected between October and December 2001 from 481 female educators working in 81 daycare centres in Montréal, Québec. Rubella IgG serology was performed using ELISA.

RESULTS

An overall seronegativity of 10.2% was found. The positive predictive value of previous rubella vaccination with seropositivity was high (92.1%). Ninety-one percent of the women were of childbearing age (= 49 years). Only 1.3% (n = 6) were currently pregnant, none of whom were seronegative. Significant predictors of seronegativity for educator- and daycare-level variables included lack of previous rubella vaccination (OR = 3.60; 95% CI: 1.43, 9.01), not having own children (OR = 3.76; 95% CI: 1.67, 8.55), age per 5-year increment (OR = 0.81; 95% CI: 0.66, 0.99), and increased number of colds in educators in the daycare centre in the last two weeks (OR = 1.15; 95% CI: 1.01, 1.31).

INTERPRETATION: The high proportion of seronegativity, in addition to the potential increased transmission in daycare centres emphasize the need for a review of the rubella vaccination recommendations and health promotion interventions targeted to this occupational group.