Time of perinatal immunization, thimerosal exposure and neurodevelopment at 6 months in breastfed infants.

Abstract

AIM:

Brazilian newborns immunized with hepatitis-B (thimerosal containing vaccine, TCV) receive the first dose within 24 h if delivered in public hospitals, but at a later time if born in private hospitals. We compared neurodevelopment (ND) in infants born in a state hospital (immunized within 24 h) and in privately run hospitals (immunized 2-4 days postnatally).

METHODS:

We used the Gesell Developmental Schedules in 82 healthy exclusively breastfed infants at 6 months to assess motor skills, language development, comprehension capacity and social skills.

RESULTS:

Compared to the group immunized 2-4 days after hospital discharge, the group immunized within 24 h showed no significant difference in ND delays. Despite the variation in gestational age (range 36-42 weeks) and TCV-ethylmercury (EtHg) dose (5.7-11.3 microg Hg/kg b.w.) at birth, time of exposure to TCV showed no significant association with ND. Gesell Developmental Score was not significantly correlated with total parenteral EtHg/unit of body mass neither with the relative increase in hair-Hg (as an additional challenge to prenatal Hg exposure).

CONCLUSION:

In breastfed infants, differences in early exposure to TCV-EtHg cannot portend clinical neurodevelopment delays at 6 months. We speculate that breastfeeding remains a significant strategy to improve central nervous system protection of infants facing early exposure challenges.

• Authors: Rejane C Marques, José G Dórea, Angelo G Manzatto, Wanderley R Bastos, José V E Bernardi, Olaf Malm
• Journal: Acta paediatrica (Oslo, Norway : 1992) (Acta Paediatr) Vol. 96 Issue 6 Pg. 864-8 (Jun 2007) ISSN: 0803-5253 [Print] Norway
• PMID: 17465985 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ethylmercury Compounds
• Hepatitis B Vaccines
• Preservatives, Pharmaceutical
• Thimerosal

Topics

• Body Weight
• Brazil
• Breast Feeding
• Developmental Disabilities (chemically induced)
• Ethylmercury Compounds (administration & dosage, adverse effects)
• Female
• Hepatitis B Vaccines (administration & dosage, chemistry)
• Humans
• Immunization Schedule
• Infant, Newborn
• Male
• Maximum Tolerated Dose
• Neuropsychological Tests
• Preservatives, Pharmaceutical (administration & dosage, adverse effects)
• Thimerosal (administration & dosage, adverse effects)
• Time Factors