Preservative in vaccines is safe

There has been widespread concern that mercury-based preservatives used in vaccines might impair the neurological development of children, but the opposite seems to be true. Immunising infants with vaccines containing the preservative thiomerosal may actually be associated with improved behaviour and mental performance.Researchers from the University of Bristol, UK, followed 12,956 children, born in 1991 and 1992, till they were about 7-1/2 years old. Information was collected on doses of containing-containing diphtheria-pertussis-tetanus (DPT) vaccines given at 3, 4, and 6 months, as well as on measures of behaviour, fine motor skills, speech and special education needs. Instead of finding that outcomes were worse with increasing exposure to thiomerosal, the researchers saw less hyperactivity and conduct problems at 47 months, better motor development at 6 months and at 30 months, and reduced difficulty with sounds and need for speech therapy.In a second study, researchers from the Communicable Disease Surveillance Centre, London, conducted a study involving 107,152 children born between 1988 and 1997. Protective effects of mercury-containing vaccine exposure for general developmental disorders, attention-deficit disorder, and unspecified developmental delay, were observed.

At present, there is no reason to change existing immunisation practices with thiomerosal-containing vaccines on grounds of safety.

COMMENT