Safety of Second-Dose Single-Antigen Varicella Vaccine.
OBJECTIVE
In 2006, routine 2-dose varicella vaccination for children was recommended to improve control of varicella. We assessed the safety of second-dose varicella vaccination.


METHODS
We identified second-dose single-antigen varicella vaccine reports in the Vaccine Adverse Event Reporting System during 2006 to 2014 among children aged 4 to 18 years. We analyzed reports by age group (4-6 and 7-18 years), sex, serious or nonserious status, most common adverse events (AEs), and whether other vaccines were administered concomitantly with varicella vaccine. We reviewed serious reports of selected AEs and conducted empirical Bayesian data mining to detect disproportional reporting of AEs.


RESULTS
We identified 14 641 Vaccine Adverse Event Reporting System reports after second-dose varicella vaccination, with 494 (3%) classified as serious. Among nonserious reports, injection site reactions were most common (48% of children aged 4-6 years, 38% of children aged 7-18 years). The most common AEs among serious reports were pyrexia (31%) for children aged 4 to 6 years and headache (28%) and vomiting (27%) for children aged 7 to 18 years. Serious reports of selected AEs included anaphylaxis (83), meningitis (5), encephalitis (16), cellulitis (52), varicella (6), herpes zoster (6), and deaths (7). One immunosuppressed adolescent was reported with vaccine-strain herpes zoster. Only previously known AEs were reported more frequently after second-dose varicella vaccination compared with other vaccines.


CONCLUSIONS
We identified no new or unexpected safety concerns for second-dose varicella vaccination. Robust safety monitoring remains an important component of the national varicella vaccination program.
Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, ezu2@cdc.gov.
John R
JR
Su
School Health Branch, Division of Population Health, National Center for Chronic Disease Prevention and Health Promotion, and.
Zanie
Z
Leroy
Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases.
Paige W
PW
Lewis
Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases.
Penina
P
Haber
Epidemiology Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; and.
Mona
M
Marin
Epidemiology Branch, Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; and.
Jessica
J
Leung
Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, US Food and Drug Administration, Silver Springs, MD.
Emily Jane
EJ
Woo
Immunization Safety Office, Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases.
Tom T
TT
Shimabukuro
D000293:Adolescent; D016907:Adverse Drug Reaction Reporting Systems; D000707:Anaphylaxis / Q000139:chemically induced; D002481:Cellulitis / Q000139:chemically induced; D002644:Chickenpox / Q000139:chemically induced; D019433:Chickenpox Vaccine / Q000008:administration & dosage / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D004660:Encephalitis / Q000139:chemically induced; D005260:Female; D005334:Fever / Q000139:chemically induced; D006261:Headache / Q000139:chemically induced; D006562:Herpes Zoster / Q000139:chemically induced; D006801:Humans; D007117:Immunization, Secondary / Q000009:adverse effects*; D008297:Male; D008582:Meningitis, Aseptic / Q000139:chemically induced; D008587:Meningitis, Viral / Q000139:chemically induced; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects; D014839:Vomiting / Q000139:chemically induced
D019433:Chickenpox Vaccine; D014613:Vaccines, Attenuated