Effectiveness of adolescent and adult tetanus, reduced-dose diphtheria, and acellular pertussis vaccine against pertussis.
BACKGROUND
Pertussis is among the most poorly controlled bacterial vaccine-preventable diseases in the United States. In 2006, a tetanus, reduced-dose diphtheria, and acellular pertussis (Tdap) booster was recommended for adolescents and adults. Tdap vaccines were licensed on the basis of antibody response without vaccine effectiveness data.


METHODS
From 30 September 2007 through 19 December 2007, a pertussis outbreak occurred at a nursery through twelfth grade school on St. Croix, US Virgin Islands. We screened all students for cough and collected clinical history, including Tdap receipt. Coughing students were offered diagnostic testing. We defined clinical case patients as students with cough 14 days in duration plus either whoop, paroxysms, or post-tussive vomiting, and we defined confirmed case patients as students with any cough with isolation of Bordetella pertussis or those with clinical cases and polymerase chain reaction or serological evidence of pertussis; other clinical cases were classified as probable.


RESULTS
There were 51 confirmed or probable cases among 499 students (attack rate, 10%). Disease clustered in grades 6-12, with a peak attack rate of 38% among 10th graders. Of 266 students aged 11 years with complete data, 31 (12%) had received Tdap. Forty-one unvaccinated students (18%) had confirmed or probable pertussis, compared with 2 (6%) of the vaccinated students (relative risk, 2.9); vaccine effectiveness was 65.6% (95% confidence interval, -35.8% to 91.3%; P = .092).


CONCLUSIONS
This first evaluation of Tdap vaccine effectiveness in the outbreak setting suggests that Tdap provides protection against pertussis. Increased coverage is needed to realize the full benefit of the vaccine program. Serological testing was an important tool for case identification and should be considered for inclusion in the Council of State and Territorial Epidemiologists case definition.
Wei
Stanley C
SC
National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Tatti
Kathleen
K
Cushing
Kimberly
K
Rosen
Jennifer
J
Brown
Kristin
K
Cassiday
Pamela
P
Clark
Thomas
T
Olans
Richard
R
Pawloski
Lucia
L
Martin
Monte
M
Tondella
Maria Lucia
ML
Martin
Stacey W
SW
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D001886:Bordetella pertussis / Q000276:immunology* / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007223:Infant; D008297:Male; D009305:Nasopharynx / Q000382:microbiology; D016133:Polymerase Chain Reaction; D014767:United States Virgin Islands / Q000453:epidemiology; D014611:Vaccination / Q000706:statistics & numerical data; D014917:Whooping Cough / Q000453:epidemiology* / Q000517:prevention & control*; D055815:Young Adult
D000907:Antibodies, Bacterial; D022681:Diphtheria-Tetanus-acellular Pertussis Vaccines; D007074:Immunoglobulin G