Considerable decrease of antibody titers against measles, mumps, and rubella in preschool children from an e-waste recycling area

Data on vaccination effects in children chronically exposed to heavy metals are extremely scarce. This study aims to investigate the immune responsiveness to measles, mumps, and rubella (MMR) vaccination in children from an e-waste recycling area. 378 healthy children from Guiyu (exposed group) and Haojiang (reference group) were surveyed. Blood lead (Pb) levels were measured by graphite furnace atomic absorption. Titers of antibodies against MMR were quantified by ELISA. Blood Pb levels of children from the exposed group were significantly higher than those from the reference group (5.61 μg/dL vs. 3.57 μg/dL, p < 0.001). In contrast, the antibody titers against MMR of the children from the exposed group were significantly lower than those from the reference group. The median titer of the anti-measles antibody of the exposed group was 669.64 mIU/mL, with an interquartile range of 372.88–1068.42 mIU/mL; this was decreased by nearly 40% compared to that of the reference group (median 1046.79 mIU/mL, interquartile range 603.29–1733.10 mIU/mL). For antibody titers against mumps, there was an about 45% decrease in the exposed group (median 272.24 U/mL, interquartile range 95.19–590.16 U/mL), compared to the reference group (median 491.78 U/mL, interquartile range 183.38–945.96 U/mL). In the case of rubella, the median titer of the antibody was also significantly lower in the exposed group (median 37.08 IU/mL, interquartile range 17.67–66.66 IU/mL) compared to the reference group (median 66.50 IU/mL, interquartile range 25.32–105.59 IU/mL); the decrease in this case was nearly 44%. The proportion of children whose antibody titers against MMR were below protective level in the exposed group was higher than it was in the reference group. The present study demonstrates that the immune responsiveness to routine vaccination was suppressed in children chronically exposed to lead. Thus, the vaccination strategies for these children living in an e-waste recycling area should be modified.