1388. Waning Protection Following 5 Doses of a 3-component DTaP Vaccine in School Age Children during California’s 2010 and 2014 Pertussis Outbreaks
Session: Oral Abstract Session: Pediatric Vaccines: Measles and Pertussis
Saturday, October 10, 2015: 11:30 AM
Room: 32--ABC
Background: The effectiveness of DTaP vaccines is known to wane substantially after the 5th dose given at 4-6 years of age. Waning immunity following 5 doses of the same type of DTaP vaccine has not been described. We investigated waning effectiveness against pertussis in California since 2006, which included large pertussis outbreaks in 2010 and more recently in 2014, following 5 doses of GlaxoSmithKline (GSK) 3-component acellular pertussis vaccines (DTaP3).

Methods: We conducted a case-control study from 01/2006 through 03/2015 among children who received 5 doses of DTaP at Kaiser Permanente Northern California, including the first 3 doses between ages 1 to 11 months, the 4th between ages 12 and 46 months, and the 5th between ages 47 and 84 months. We compared time since the 5th dose in confirmed pertussis polymerase chain reaction (PCR)-positive cases with pertussis PCR-negative controls. We used logistic regression adjusted for calendar time, age, sex, race, and service area to estimate the effect of time since the 5th DTaP dose on the odds of pertussis. We evaluated all DTaP vaccines, focusing on the subgroup of cases and controls whose 5 doses were all DTaP3. We excluded individuals who received another pertussis-containing vaccine (e.g., Tdap) before the PCR test, received the 5th DTaP < 2 weeks before the PCR test, previously tested positive for pertussis or who were >12 years at the PCR test.

Results: The study population of 4-12 year olds included 340 pertussis cases and 3,843 PCR-negative controls after 5 doses of DTaP3 and 462 pertussis cases and 5,653 PCR-negative controls after 5 doses of any DTaP. The majority of doses in the study population were DTaP3 (86.8%). Comparing pertussis cases with PCR-negative controls yielded odds ratios of 1.27 per year (95% CI 1.10-1.46) after 5 doses of DTaP3 and 1.30 per year (95% CI 1.15-1.46) after any 5 DTaP vaccines. The odds of acquiring pertussis increased by an average of 27% per year after the 5th dose of DTaP3.

Conclusion: Waning protection after DTaP3 was similar to that following 5 doses of any type of DTaP vaccines, however this finding is not unexpected because most of the DTaP vaccines administered were DTaP3. Following 5 doses of GSK DTaP3 vaccines, protection from pertussis waned 27% per year on average.

Nicola P. Klein, MD, PhD1, Joan Bartlett, MPH, MPP1, Bruce Fireman, MA1, Laurie Aukes, RN1, Philip Buck, PhD2, Girishanthy Krishnarajah, Ph.D.3 and Roger Baxter, MD, FIDSA1, (1)Kaiser Permanente Vaccine Study Center, Oakland, CA, (2)GlaxoSmithKline, Philadelphia, PA, (3)US Health Outcomes & Epidemiology - Vaccines USMA Health Outcomes, GlaxoSmithKline: USHO Vaccines, Philadelphia, PA

Disclosures:

N. P. Klein, GSK: Grant Investigator , Research grant
Sanofi Pasteur: Grant Investigator , Research grant
Pfizer: Grant Investigator , Research grant
Merck: Grant Investigator , Research grant
Novartis: Grant Investigator , Research grant
Nuron Biotech: Grant Investigator , Research grant
Protein Science: Grant Investigator , Research grant and Research support
MedImmune: Grant Investigator , Research grant

J. Bartlett, None

B. Fireman, None

L. Aukes, None

P. Buck, GSK: Employee and Shareholder , Salary

G. Krishnarajah, GSK: Employee and Shareholder , Salary

R. Baxter, Merck: Grant Investigator , Research grant
GSK: Grant Investigator , Research grant
Pfizer: Grant Investigator , Research grant
Sanofi Pasteur: Grant Investigator , Research grant

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