Identifying critical windows of susceptibility to perinatal lead exposure on child serum vaccine antibody levels

Mounting evidence suggests that early-life lead exposure alters immune system functions, including T-cell–dependent antibody responses to childhood immunizations. However, no studies have identified critical windows of susceptibility to lead exposure. The aim of this study was to identify perinatal critical windows of lead exposure that are associated with antibody responses to anti-MMR (measles, mumps, and rubella virus) and anti-DTP (anti-diphtheria, tetanus, and pertussis toxoids) vaccinations in Hispanic school-aged (mean ± standard deviation: 4.8 ± 0.6 years) children. Weekly lead exposure—from 16 weeks before to 14 weeks after birth—was measured in deciduous teeth from 271 children enrolled in the PROGRESS study. Serum levels of anti-MMR and anti-DTP antibodies were measured by a Luminex multiplexed microbead array immunoassay. Time-varying associations between log2-transformed dentine lead concentrations and log2-transformed antibody levels were estimated by fitting distributed lag nonlinear models. A 2-fold higher dentine lead concentration in the first 3 weeks postpartum was associated with an average –4.29% lower antitetanus level (95% CI, –8.22 to –0.20). A perinatal (1 week before to 1 week after birth) critical window of lead exposure demonstrated an average –3.44% (95% CI, –7.05 to 0.30) lower anti-diphtheria antibody level. Our study suggests that early-life lead exposure may contribute to immune dysfunction by reducing children’s antibody responses to scheduled vaccinations.