Tdap vaccine effectiveness in adolescents during the 2012 Washington State pertussis epidemic.
BACKGROUND
Acellular pertussis vaccines replaced whole-cell vaccines for the 5-dose childhood vaccination series in 1997. A sixth dose of pertussis-containing vaccine, tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis, adsorbed (Tdap), was recommended in 2005 for adolescents and adults. Studies examining Tdap vaccine effectiveness (VE) among adolescents who have received all acellular vaccines are limited.


METHODS
To assess Tdap VE and duration of protection, we conducted a matched case-control study during the 2012 pertussis epidemic in Washington among adolescents born during 1993-2000. All pertussis cases reported from January 1 through June 30, 2012, in 7 counties were included; 3 controls were matched by primary provider clinic and birth year to each case. Vaccination histories were obtained through medical records, the state immunization registry, and parent interviews. Participants were classified by type of pertussis vaccine received on the basis of birth year: a mix of whole-cell and acellular vaccines (1993-1997) or all acellular vaccines (1998-2000). We used conditional logistic regression to calculate odds ratios comparing Tdap receipt between cases and controls.


RESULTS
Among adolescents who received all acellular vaccines (450 cases, 1246 controls), overall Tdap VE was 63.9% (95% confidence interval [CI]: 50% to 74%). VE within 1 year of vaccination was 73% (95% CI: 60% to 82%). At 2 to 4 years postvaccination, VE declined to 34% (95% CI: -0.03% to 58%).


CONCLUSIONS
Tdap protection wanes within 2 to 4 years. Lack of long-term protection after vaccination is likely contributing to increases in pertussis among adolescents.
Epidemic Intelligence Service, Scientific Education and Professional Development Program Office, Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and amacosta@cdc.gov.
Anna M
AM
Acosta
Communicable Disease Epidemiology, Washington State Department of Health, Shoreline, Washington.
Chas
C
DeBolt
Communicable Disease Epidemiology, Washington State Department of Health, Shoreline, Washington.
Azadeh
A
Tasslimi
Biostatistics Office, Division of Bacterial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; and.
Melissa
M
Lewis
Communicable Disease Epidemiology, Washington State Department of Health, Shoreline, Washington.
Laurie K
LK
Stewart
Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and.
Lara K
LK
Misegades
Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and.
Nancy E
NE
Messonnier
Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and.
Thomas A
TA
Clark
Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and.
Stacey W
SW
Martin
Meningitis and Vaccine Preventable Disease Branch, Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, and.
Manisha
M
Patel
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D008297:Male; D014861:Washington / Q000453:epidemiology; D014917:Whooping Cough / Q000453:epidemiology* / Q000517:prevention & control*
D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines
adolescent; diphtheria-tetanus-acellular pertussis vaccine; diphtheria-tetanus-pertussis vaccine; whooping cough