Delayed MMR Creates More Risk

Delayed MMR

According to a just- released study, delaying your child’s measles vaccination could create more risk.

The measles vaccine is generally given as a combined shot, with either mumps and rubella (MMR) or mumps and rubella and a separate varicella (chicken pox) vaccine (MMR+V).

The researchers claim that when vaccines containing measles are given at 16 to 23 months of age there is a greater risk of the child having a high fever – and febrile seizures – than if the vaccine is administered between 12 and 15 months of age.

They also say that when children are given the measles vaccine during the second year of life, there is a two-week period following the vaccination – when virus replication is at its highest – that children are at greater risk of having a high fever.  Having a very high fever can cause some children to have a seizure.

Dr. Nicola Klein, who is a co-author of the study and co-director of the Vaccine Study Center, notes, however, that the overall risk of having a seizure following an MMR, whether delayed or not, is still fairly small.  About one child in 1,000 who receives the vaccine will go on to have a fever-related seizure.

To perform the study, the scientists took data collected from the Vaccine Safety Datalink, a project involving coordination between the Centers for Disease Control and Prevention (CDC) and a group of nine managed healthcare organizations.    From this data, they were able to analyze the records of 840,348 one-year-old children who had received the measles vaccine in any form during the year 2011.

They found that the children were at greater risk of having fever and seizures somewhere between seven and ten days after receiving the vaccine.

They also observed that the risk of fever gradually lessened the older the children became; but, the risk for seizures was greatest at around the 16-18 month mark.

The relative risk for having a fever and seizures during the 7- to 10-day window following vaccination was greater in the children 16 to 23 months of age than it was for those under 16 months.

And, they also found that children who received a combined measles, mumps, rubella and varicella vaccination (MMRV) were at greater risk for fever and accompanying seizures than those who received the varicella vaccine separately from the others (MMR+V).  This finding confirms previous research and backs up a CDC recommendation that children receive the varicella vaccine separately from the others.

While the authors did not state what had prompted them to conduct the study, it may have been the fact that more and more parents are choosing to give a delayed MMR in the hopes that it will reduce autism risk.  The current body of medical literature on the topic seems to refute any type of link between autism and the MMR; and, the original research article which started the controversy has since been proven to be a fraud.   Yet, concerns still persist.

The study was published online on October 14, 2013 in the journal JAMA Pediatrics.

Written by:  Nancy Schimelpfening


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