Diphtheria, tetanus, and varicella immunity in health care workers in neonatal units

BackgroundSusceptible health care workers are at risk of acquiring and transmitting vaccine-preventable diseases to or from patients. The objective of this study was to assess antibody levels against diphtheria, tetanus, and varicella in healthcare workers.MethodsAntibody levels against diphtheria, tetanus, and varicella were measured in health care professionals in 2 neonatal units at the Federal University of São Paulo, Brazil.ResultsBetween September and November 2002, 215 of 222 (96.8%) health care workers were studied. Of those, 122 (56.7%) gave oral information regarding their vaccination status against diphtheria and tetanus and only 9 (4.2%) had their vaccination cards. Geometric mean antibody levels against diphtheria, tetanus, and varicella were 0.89 IU/mL (95%CI, 0.73 to 1.08), 0.86 IU/mL (95%CI, 0.68 to 1.07) and 1.10 IU/mL (95%CI, 0.98 to 1.24), respectively. Using internationally accepted definitions, 200 (93.0%) and 182 (84.7%) individuals had full protection against diphtheria and tetanus, respectively. Regarding varicella, 213 (99.1%) individuals were immune and 2 (0.9%) had equivocal immunity against varicella. Of 65 (30.2%) individuals without previous history of the illness, 63 (96.9%) were immune against varicella zoster virus.ConclusionsBased on serologic screening, most professionals were immune to diphtheria, tetanus, and varicella. Absence of previous history of varicella was an unreliable identifier of susceptibility to varicella zoster virus in the health care workers studied.