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- Silfverdal, Sven Arne, et al.
(author)
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Protection against clinical pertussis induced by whole-cell pertussis vaccination is related to primo-immunisation intervals
- 2007
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In: Vaccine. - Guildford : Butterworths. - 0264-410X .- 1873-2518. ; 25:43, s. 7510-7515
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Journal article (peer-reviewed)abstract
- AIMS: Information on subjects who had at least three immunisations against pertussis was provided by longitudinal data from the 1970 British Cohort Study (BCS70) and used to assess whether three whole-cell pertussis (wP) immunisations given within less than 5 months confer less effective protection in childhood compared with a schedule with a longer interval.METHODS: Age at pertussis infection was the dependent variable in a Cox regression analysis, to investigate associations with duration between first and third pertussis immunisation; with third immunisation modelled as a time-dependent covariate. Adjustment was for number of pertussis immunisations (three or four), sex, social class and other potential confounding factors.RESULTS: A total of 8545 children were included in the analysis and 556 had a history of whooping cough. A duration of over 4 months between first and third pertussis immunisations is statistically significantly associated with a reduced risk of pertussis infection by age 10 years, compared with three immunisations given over a shorter period, producing a statistically significant adjusted hazard ratio of 0.74 (0.62-0.92). A fourth immunisation against pertussis further enhanced the protective effect with a hazard ratio of 0.59 (0.44-0.82).CONCLUSION: These results were based on a historical UK cohort using wP vaccine, and indicate that a vaccination schedule with an interval between the immunisations greater than 4 months, and also including a fourth immunisation, would be more effective in this population than a three dose schedule within a shorter interval without booster.
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