Febrile Seizure Risk After Vaccination in Children 6 to 23 Months.
An increased risk of febrile seizure (FS) was identified with concomitant administration of trivalent inactivated influenza vaccine (IIV3) and pneumococcal conjugate vaccine (PCV) 13-valent during the 2010-2011 influenza season. Our objective was to determine whether concomitant administration of IIV3 with other vaccines affects the FS risk.



We examined the risk of FS 0 to 1 day postvaccination for all routinely recommended vaccines among children aged 6 through 23 months during a period encompassing 5 influenza seasons (2006-2007 through 2010-2011). We used a population-based self-controlled risk interval analysis with a control interval of 14 to 20 days postvaccination. We used multivariable regression to control for receipt of concomitant vaccines and test for interaction between vaccines.



Only PCV 7-valent had an independent FS risk (incidence rate ratio [IRR], 1.98; 95% confidence interval [CI], 1.00 to 3.91). IIV3 had no independent risk (IRR, 0.46; 95% CI, 0.21 to 1.02), but risk was increased when IIV3 was given with either PCV (IRR, 3.50; 95% CI, 1.13 to 10.85) or a diphtheria-tetanus-acellular-pertussis (DTaP)-containing vaccine (IRR, 3.50; 95% CI, 1.52 to 8.07). The maximum estimated absolute excess risk due to concomitant administration of IIV3, PCV, and DTaP-containing vaccines compared with administration on separate days was 30 FS per 100 000 persons vaccinated.



The administration of IIV3 on the same day as either PCV or a DTaP-containing vaccine was associated with a greater risk of FS than when IIV3 was given on a separate day. The absolute risk of postvaccination FS with these vaccine combinations was small.
Immunization Safety Office, US Centers for Disease Control and Prevention, Atlanta, Georgia; jduffy@cdc.gov.
Jonathan
J
Duffy
Immunization Safety Office, US Centers for Disease Control and Prevention, Atlanta, Georgia;
Eric
E
Weintraub
Institute for Health Research, Kaiser Permanente Colorado and Ambulatory Care Services, Denver Health, Denver, Colorado;
Simon J
SJ
Hambidge
Group Health Research Institute, Seattle, Washington;
Lisa A
LA
Jackson
HealthPartners Institute for Education and Research, Minneapolis, Minnesota;
Elyse O
EO
Kharbanda
Kaiser Permanente Vaccine Study Center, Kaiser Permanente Northern California, Oakland, California;
Nicola P
NP
Klein
Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts;
Grace M
GM
Lee
Kaiser Permanente Southern California, Pasadena, California;
S Michael
SM
Marcy
Kaiser Permanente Hawaii, Honolulu, Hawaii;
Cynthia C
CC
Nakasato
Kaiser Permanente Northwest, Portland, Oregon; and.
Allison
A
Naleway
Kaiser Permanente Georgia, Atlanta, Georgia.
Saad B
SB
Omer
Immunization Safety Office, US Centers for Disease Control and Prevention, Atlanta, Georgia;
Claudia
C
Vellozzi
Immunization Safety Office, US Centers for Disease Control and Prevention, Atlanta, Georgia;
Frank
F
DeStefano
D005260:Female; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects*; D008297:Male; D018570:Risk Assessment; D003294:Seizures, Febrile / Q000453:epidemiology* / Q000209:etiology*; D014611:Vaccination / Q000009:adverse effects*
D007252:Influenza Vaccines