New Delhi: Routine childhood vaccinations are not associated with an increased risk of epilepsy in young children, according to a new study led by the US Centers for Disease Control and Prevention. 

Vaccine aluminum adjuvants found safe, researchers say

The study, published in The Journal of Pediatrics, showed that the aluminum used as vaccine adjuvants also does not increase the risk of the neurological condition.

“Incident epilepsy was not associated with up-to-date vaccination status or cumulative vaccine aluminum exposure among children less than 4 years of age,” said the team, including those from the Marshfield Clinic Research Institute in Marshfield, US.

The study included 2,089 children diagnosed as having epilepsy from age 1 year to less than 4 years. These were compared with 20,139 children without epilepsy based on age, sex, and health care site.

The majority of the kids were boys (54 per cent) and between the ages of 1 year and 23 months (69 per cent). No higher risk following the childhood vaccine schedule was observed, stated the researchers.

To assess vaccine exposure, the team examined the schedule for routine childhood vaccines and their cumulative aluminum exposure from vaccine adjuvants, measured in milligrams.

Aluminum salts -- including formulations of aluminum hydroxide (AH), amorphous aluminum hydroxyphosphate sulfate, aluminum phosphate (AP), combined AH and AP (AH/AP), and aluminum potassium sulfate --are commonly used as adjuvants in vaccines. While this helps to enhance immune response, it has been a focus of safety concerns.

However, the team found that neither measure was associated with a higher risk of epilepsy.

Known medical and neurological factors raise epilepsy risk, not vaccines

“The adjusted odds ratios for both measures did not exceed 1.0. Children with previously established risk factors for epilepsy, including those born prematurely, those with a history of epilepsy, and those with underlying neurologic or medical conditions, had substantially higher odds of developing the condition,” the team said.

A subgroup analysis suggested that very young infants (1 to 2 months old) who received vaccines containing the adjuvant combination AH/AP appeared to have about twice the odds of an epilepsy diagnosis compared with those who did not, but the odds did not quite reach statistical significance.

“Overall, this study provides additional reassurance on the safety of the childhood vaccine schedule at a time when vaccination coverage has declined in some populations," the researchers said.

"These results may help providers communicate with parents concerned about potential risks of epilepsy,” they added.

(IANS)