Quinn H.E.,University of Sydney |
Snelling T.L.,University of Western Australia |
Habig A.,National Center for Immunisation Research and Surveillance of Vaccine Preventable Diseases and |
Chiu C.,University of Sydney |
And 2 more authors.
Pediatrics | Year: 2014
BACKGROUND: Although recommended for almost a decade, evidence for field effectiveness of vaccinating close adult contacts of newborn infants against pertussis ("cocooning") is lacking. We evaluated the impact of a government-funded cocoon program during a pertussis epidemic in New South Wales, Australia.METHODS: We matched all New South Wales laboratory-confirmed pertussis cases aged <4 months with onset between April 1, 2009, to March 30, 2011 to controls from the state birth register by date of birth and area of residence. Parental vaccine receipt was by self-report, with a subset verified. Parents were considered "immunized" if vaccinated ≥4 weeks before case symptom onset. The effectiveness of parental immunization (versus neither vaccinated) was quantified as (1 - odds ratio) × 100%.RESULTS: Case households had fewer immunized mothers (22% vs 32%) or fathers (20% vs 31%) but were more likely to include additional and older children. After adjustment, when both parents met our definition of immunized, risk of pertussis at<4 months of age was reduced by 51% (95% confidence interval 10% to 73%). Maternal vaccination prepregnancy and an immunized father reduced the risk by 51% (95% confidence interval 0% to 76%).CONCLUSIONS: Timely parental pertussis boosters provided significant protection. Evidence of protection from maternal vaccination prepregnancy is biologically plausible, and more precise data on the magnitude and duration of this is important for future policy recommendations. Copyright © 2014 by the American Academy of Pediatrics.
PubMed | National Center for Immunisation Research and Surveillance of Vaccine Preventable Diseases and
Type: Journal Article | Journal: Pediatrics | Year: 2014
Data on the effectiveness of the diphtheria-tetanus-acellular pertussis (DTaP) vaccine in the first 4 years of life are sparse. We evaluated the vaccine effectiveness (VE) of 1 and 2 doses of DTaP before 6 months of age and of 3 doses from 6 months of age in Australia, where, since 2003, a fourth dose is not given until 4 years.We matched reported pertussis cases aged 2 to 47 months between January 2005 and December 2009 to controls from a population-based immunization register by date of birth and region of residence. VE by number of doses and age group was calculated as (1 - odds ratio) 100%.VE against hospitalization increased from 55.3% (95% confidence interval [CI], 42.7%-65.1%) for 1 dose before 4 months of age to 83.0% (95% CI, 70.2%-90.3%) for 2 doses before 6 months. The VE of 3 doses of DTaP against all reported pertussis was 83.5% (95% CI, 79.1%-87.8%) between 6 and 11 months, declining to 70.7% (95% CI, 64.5%-75.8%) between 2 and 3 years of age and 59.2% (95% CI, 51.0%-66.0%) between 3 and 4 years of age.DTaP provided good protection against pertussis in the first year of life from the first dose. Without a booster dose, the effectiveness of 3 doses waned more rapidly from 2 to 4 years of age than previously documented for children >6 years of age who had received 5 doses.