Earlier Measles Vaccinations Provide Better Health Outcomes In Children
October 15, 2013

Earlier Measles Vaccinations Provide Better Health Outcomes In Children

Brett Smith for redOrbit.com - Your Universe Online

While measles vaccinations can be lifesaving for a young child, they are linked to a small risk of fever and even seizures that are caused by the child’s body fighting off the vaccine’s weakened form of the virus.

While the risk of these negative side effects is considered extremely low, parents can cut their child’s risk even further by vaccinating them at 12 to 15 months of age instead of waiting until their child is 16 to 23 months old, according to a new study published in JAMA Pediatrics.

The Centers for Disease Control and Prevention (CDC) advises that children receive a two-dose series of measles vaccines, with the first given at 12 to 15 months and the second when the child is between 4 and 6 years old. Children typically get their first dose of the vaccine between the ages of 12 and 23 months, with about 85 percent of children getting it by 19 months of age.

"We found that the magnitude of increased risk of fever and seizures following immunization with measles-containing vaccines during the second year of life depends on age," said study author Dr. Ali Rowhani-Rahbar, an epidemiologist at the University of Washington. "While measles-containing vaccines administered at 12-15 months of age are associated with a small risk of fever and seizures following immunization, delayed administration at 16-23 months of age results in a greater risk of those adverse events."

Past research has indicated that measles vaccines given to children between 12 and 23 months of age are related to an increased risk of febrile, or fever-induced, seizures one to two weeks after immunization, when the weakened virus within the vaccine is at its peak replication. The virus proliferation can potentially spark a fever and a resulting seizure. After measles immunization, the occurrence of fever and seizures was most frequent for seven to ten days after receiving the shot than for any other period of time for all age groups.

"This study's findings reinforce for parents that these vaccines are safer when children receive them at 12 to 15 months of age,” said study author Matthew F. Daley, a pediatrician and senior investigator at Kaiser Permanente Colorado's Institute for Health Research.

While fever-induced seizures are the most frequent negative neurologic events after a measles immunization, study author Dr. Nicola Klein, emphasized that the risk is relatively small.

"Medically attended febrile seizures following immunization with measles-containing vaccines are not common events,” said Klein, a vaccine researcher at Kaiser. “Concerned parents should understand that the risk for febrile seizures after any measles-containing vaccine is low — less than one febrile seizure per 1,000 injections."

Using data from a collaborative project by the CDC and nine managed care organizations, study researchers looked at the effect of age on the risk of fever and seizures after immunization with respect to a wide range of vaccine typically administered during early childhood. The study included the records of more than 840,000 children who had been administered a measles-containing vaccine between January 2001 and December 2011.