R code, survival curves.

Background
Asthma is among the commonest noncommunicable diseases of childhood and often occurs with other atopic comorbidities. A previous case-control study found evidence that compared to children who received acellular pertussis (aP) vaccines in early infancy, children who received one or more doses of whole-cell pertussis (wP) vaccine had lower risk of developing IgE-mediated food allergy. We hypothesized that wP vaccination in early infancy might protect against atopic asthma in childhood.
Methods
Retrospective record-linkage cohort study of children between 5 and < 15 years old and born between January 1997, and December 1999, in the Australian states of Western Australia (WA) and New South Wales (NSW), receiving wP versus aP vaccine as the first pertussis vaccine dose. The main outcome and measures were first and recurrent hospitalizations for asthma; hazard ratios (HRs) and 95% confidence intervals (CIs) were computed by means of Cox and Andersen and Gill models.
Results
274,405 children aged between 5 and < 15 years old (78.4% NSW-born) received a first dose of either wP (67.8%) or aP vaccine before 4 months old. During the follow-up period, there were 5,905 hospitalizations for asthma among 3,955 children. The incidence rate for first hospitalization was 1.5 (95% CI 1.4–1.5) per 1,000 child-years among children receiving wP vaccine as a first dose, and 1.5 (95% CI 1.4–1.6) among those vaccinated with aP vaccine as a first dose. The adjusted HRs for those who received wP vaccine versus aP vaccine as the first dose were 1.02 (95% CI 0.94–1.12) for first hospitalizations and 1.07 (95% CI 0.95–1.2) for recurrent hospitalizations for asthma.
Conclusions
We found no convincing evidence of a clinically relevant association between receipt of wP versus aP vaccines in early infancy and hospital presentations for asthma in childhood.

Background
哮喘是儿童最常见的非传染性疾病之一，常伴随其他特应性共病。既往一项病例对照研究发现，与婴儿早期接种无细胞百日咳（acellular pertussis, aP）疫苗的儿童相比，接种过1剂或多剂全细胞百日咳（whole-cell pertussis, wP）疫苗的儿童发生IgE介导的食物过敏的风险更低。我们提出假说：婴儿早期接种wP疫苗或可预防儿童特应性哮喘。
Methods
本研究为回顾性记录关联队列研究，研究对象为1997年1月至1999年12月期间出生、年龄介于5岁至<15岁的儿童，均来自澳大利亚西澳大利亚州（Western Australia, WA）与新南威尔士州（New South Wales, NSW），且以wP或aP疫苗作为首剂百日咳疫苗。本研究的主要结局与测量指标为哮喘首次住院及复发住院；通过Cox模型与Andersen-Gill模型计算风险比（hazard ratio, HR）及95%置信区间（confidence interval, CI）。
Results
共计274405名年龄介于5岁至<15岁的儿童（其中78.4%为新南威尔士州出生）在4月龄前接种了首剂wP疫苗（占比67.8%）或aP疫苗。随访期间，共计3955名儿童累计发生5905次哮喘住院事件。首剂接种wP疫苗的儿童，哮喘首次住院发生率为1.5例/千人年（95%置信区间：1.4~1.5）；首剂接种aP疫苗的儿童该发生率为1.5例/千人年（95%置信区间：1.4~1.6）。校正后，首剂接种wP疫苗相较于aP疫苗的儿童，哮喘首次住院的校正HR为1.02（95%置信区间：0.94~1.12），复发住院的校正HR为1.07（95%置信区间：0.95~1.20）。
Conclusions
本研究未发现具有临床说服力的证据表明，婴儿早期接种wP疫苗与aP疫苗，与儿童因哮喘住院之间存在具有临床相关性的关联。