Norwegian Institute of Public Health, Lovisenberggata 6 & 8, 0456 Oslo, Norway; European Program for Intervention Epidemiology Training, European Centre for Disease Prevention and Control, Gustav III:s Boulevard 40, 169 73 Solna, Sweden.
Norwegian Institute of Public Health, Lovisenberggata 6 & 8, 0456 Oslo, Norway.
Vaccine. 2022 May 20;40(23):3142-3149. doi: 10.1016/j.vaccine.2022.04.038. Epub 2022 Apr 22.
The acellular pertussis vaccine has been used in the Norwegian national immunisation program since 1998. Following an increase in pertussis incidence in all age groups, booster doses were introduced for 7-8-year-olds in 2006, and for 15-16-year-olds in 2013. We assessed the effects of the booster doses on pertussis incidence in different age groups to inform potential changes in vaccination policy.
We included all pertussis cases notified to the Norwegian Surveillance System for Communicable Diseases in 1998-2019. We calculated annual incidence rates (IR, per 100,000 inhabitants) by age group. We estimated average annual changes in IRs (incidence rate ratios, IRR) for each age group for 2006-2012 and 2013-2019 using Poisson regression.
In 1998-2019, 74,675 cases of pertussis were notified. Coinciding with booster introduction, between 2006 and 2012 the IR decreased among 8-15-year-olds (from 433 to 199/100,000, IRR 0.89 [95% confidence interval 0.88-0.90]). A similar decrease was seen between 2013 and 2019 among 16-19-year-olds (from 171 to 77/100,000, IRR 0.84 [0.82-0.86]). There was no significant change in IRs among children < 1 year of age between 2006 and 2012 (IRR 0.99 [0.95-1.04]) or 2013-2019 (IRR 0.96 [0.91-1.02]). The IR decreased in both periods among adults aged 20-39 and 40+ (IRR 0.94 [0.93-0.95] and 0.92 [0.91-0.92] in 2006-2012; IRR 0.97 [0.96-0.99] and 0.97 [0.96-0.99] in 2013-2019, respectively). Despite steady, high vaccination coverage, in 2013-2019, there was an increase in the IR among children aged 1-7 (63 to 86/100,000, IRR 1.05 [1.03-1.07]) and 8-15 years (88 to 122/100,000, IRR 1.08 [1.06-1.10]).
Pertussis booster doses have offered direct protection in the targeted age groups. Our findings suggest indirect protection in adults, while the incidence in infants hasn't changed. The recent increase in IRs among 1-15-year-olds warrants close monitoring and further evaluation of the vaccination schedule.
自 1998 年以来，无细胞百日咳疫苗已在挪威国家免疫计划中使用。在所有年龄组百日咳发病率增加后，2006 年为 7-8 岁儿童接种了加强针，2013 年为 15-16 岁儿童接种了加强针。我们评估了加强剂量对不同年龄组百日咳发病率的影响，为潜在的疫苗接种政策变化提供信息。
我们将所有向挪威传染病监测系统报告的百日咳病例都包括在内。我们按年龄组计算了每年的发病率（每 10 万人中的发病率）。我们使用泊松回归估计了 2006-2012 年和 2013-2019 年每个年龄组的发病率平均年变化率（发病率比，IRR）。
在 1998-2019 年期间，报告了 74675 例百日咳病例。随着加强针的推出，2006 年至 2012 年期间，8-15 岁人群的发病率下降（从 433 例降至 199 例/10 万人，IRR 0.89 [95%置信区间 0.88-0.90]）。2013 年至 2019 年期间，16-19 岁人群的发病率也出现了类似的下降（从 171 例降至 77 例/10 万人，IRR 0.84 [0.82-0.86]）。2006 年至 2012 年期间，<1 岁儿童的发病率没有显著变化（IRR 0.99 [0.95-1.04]）或 2013-2019 年期间（IRR 0.96 [0.91-1.02]）。在 20-39 岁和 40 岁及以上的成年人中，这两个时期的发病率都有所下降（IRR 0.94 [0.93-0.95]和 0.92 [0.91-0.92]在 2006-2012 年；IRR 0.97 [0.96-0.99]和 0.97 [0.96-0.99]在 2013-2019 年，分别）。尽管疫苗接种率保持稳定且很高，但在 2013-2019 年期间，1-7 岁儿童（从 63 例增至 86 例/10 万人，IRR 1.05 [1.03-1.07]）和 8-15 岁儿童（从 88 例增至 122 例/10 万人，IRR 1.08 [1.06-1.10]）的发病率有所增加。
百日咳加强针在目标年龄组提供了直接保护。我们的研究结果表明，成年人存在间接保护，而婴儿的发病率没有变化。最近 1-15 岁人群发病率的增加需要密切监测，并进一步评估疫苗接种计划。
