Risk of human parvovirus B19 infections among school and hospital employees during endemic periods.

Because human parvovirus B19 (B19) infections are common in children, and maternal infection of pregnant women may cause fetal death, risk factors for B19 infections for hospital and school employees were identified during an endemic period. By serologic testing, 2730 employees of 135 schools in three school systems and 751 employees of a hospital were monitored. Of these, 60% were initially seropositive. After adjusting for age, race, and gender, risk factors for seropositivity were contact with children 5-18 years old at home (odds ratio [OR] = 1.2), at work (OR = 1.2), and employment in elementary schools in school system 2 (OR = 1.4). Over 42 months, 1 of 198 susceptible hospital employees seroconverted versus 62 of 927 school employees. Four factors associated with seroconversion were employment at elementary schools in system 2, contact with children 5-11 years old at home or with children 5-18 years old at work, and age < 30 years. Those in daily contact with school-age children had a fivefold increased annual occupational risk for B19 infection.