Coadministration of Flu, Pneumococcal Vaccines Linked to Febrile Seizures

From Medscape Medical News

Emma Hitt, PhD

February 25, 2011 — Trivalent inactivated flu vaccine (TIV) administered concurrently with the 13-valent pneumococcal conjugate vaccine (PCV13) appears to be associated with an increased risk for febrile seizure in children age 6 months to 23 months, according to the US Centers for Disease Control and Prevention (CDC).

Frank DeStefano, MD, MPH, from the CDC's Immunization Safety Office, and Grace M. Lee, MD, MPH, from Harvard Medical School, in Boston, Massachusetts, presented data and discussed the issue at the Advisory Committee on Immunization Practices (ACIP) meeting held here in Atlanta, Georgia, on Wednesday and Thursday this week.

According to Dr. DeStefano, fever after vaccination is a common event and can potentially increase the risk for febrile seizures.

Vaccines associated with febrile seizures include whole-cell pertussis vaccines, measles-containing vaccines, and the 2010 TIV for the southern hemisphere, specifically the brand manufactured by CSL Biotherapies (Fluvax and Fluvax Juniors, used in Australia and New Zealand only).

Preliminary results from the Vaccine Safety Datalink suggest that the 2010/2011 TIV used in the United States is not associated with an increased risk for febrile seizure in children 6 months to 23 months of age, unless administered at the same time as PCV13.

Dr. DeStefano estimates that TIV and PCV13 coadministration may account for about 60 seizures per 100,000 children and that such seizures typically occur the day after vaccination.

"Febrile seizures associated with vaccine administration are associated with a good prognosis, although they can scare parents and caregivers," he said.

ACIP also cast a final vote regarding the use of a booster vaccine against Japanese encephalitis virus. A purified, inactivated vaccine derived from an attenuated strain of Japanese encephalitis virus vaccine, Ixiaro, was licensed for use as a booster in October 2010 after its initial approval in 2009.

The vaccine requires a 2-dose series, but guidelines for a booster dose had not been established; ACIP voted that a booster dose before potential exposure to the virus should be given if the primary series of Ixiaro was administered more than a year ago.

The vaccine is recommended for travelers who may be exposed to endemic Japanese encephalitis virus for more than a month as well as laboratory workers.