Born B, Coombs A, Ryan V, LaFreniere M, Earle L, Fleming S, Fitzgerald A, Atherton F
Centre for Public Health Infrastructure, Public Health Agency of Canada, Ottawa, ON.
Department of Health and Wellness, Halifax, NS.
Can Commun Dis Rep. 2017 Feb 2;43(2):49-55. doi: 10.14745/ccdr.v43i02a03.
Pertussis can cause a serious respiratory bacterial infection, especially in infants. Between January 1 and December 31, 2015, there was an increase in the number of reported pertussis cases in Nova Scotia (NS). Surveillance practices for pertussis in NS were challenging because immunization coverage data are not available and rate information was neither timely nor precise with respect to geography. Public health officials in NS decided to adopt a new surveillance technique to inform public health actions across the Province.
To assess the use of a 40-day rolling incidence rate to monitor pertussis activity in Nova Scotia.
A 40-day rolling incidence rate was calculated for pertussis by age groups and various levels of geography. Public health authorities continued to anticipate new cases of pertussis if the contacts of known cases were still within the incubation period (range between six and 20 days). The 40-day incubation period was chosen to reflect twice the incubation period's upper range. Rates were calculated using Statistics Canada population projections for 2014 and then compared with traditional case counts and cumulative incidences. The usefulness of the statistics was assessed by public health decision makers.
Increased pertussis activity was noted across NS, most notably in the South West region. The use of a 40-day rolling incidence rate as a surveillance tool provided more timely and geographically precise descriptions of ongoing trends in pertussis activity and helped to inform appropriate public health action. Health officials valued the information provided from the rolling incidence because it allowed them to manage activities based on weekly estimates at various levels of geography.
Rolling incidence proved to be a useful tool to monitor a cyclical increase in pertussis cases in Nova Scotia and to inform related public health actions. The rolling incidence provided geographically precise and timely information that was useful to estimate new cases in the absence of reliable immunization coverage information. This method could supplement traditional epidemiological surveillance of future communicable disease events, especially those characterized by long incubation periods and low case counts.
百日咳可引发严重的呼吸道细菌感染，尤其是在婴儿中。2015年1月1日至12月31日期间，新斯科舍省（NS）报告的百日咳病例数量有所增加。NS省的百日咳监测工作具有挑战性，因为无法获取免疫接种覆盖率数据，且发病率信息在地理方面既不及时也不准确。NS省的公共卫生官员决定采用一种新的监测技术，为全省的公共卫生行动提供信息。
评估使用40天滚动发病率来监测新斯科舍省百日咳活动情况。
按年龄组和不同地理级别计算百日咳的40天滚动发病率。如果已知病例的接触者仍处于潜伏期（6至20天），公共卫生当局继续预期会出现新的百日咳病例。选择40天的潜伏期以反映潜伏期上限的两倍。发病率使用加拿大统计局2014年的人口预测数据进行计算，然后与传统的病例数和累积发病率进行比较。公共卫生决策者评估了这些统计数据的有用性。
整个NS省的百日咳活动均有增加，最显著的是在西南地区。使用40天滚动发病率作为监测工具，能更及时、更准确地描述百日咳活动的当前趋势，并有助于采取适当的公共卫生行动。卫生官员重视滚动发病率提供的信息，因为这使他们能够根据不同地理级别每周的估计情况来管理各项活动。
滚动发病率被证明是监测新斯科舍省百日咳病例周期性增加并为相关公共卫生行动提供信息的有用工具。在缺乏可靠的免疫接种覆盖率信息的情况下，滚动发病率提供了地理上精确且及时的信息，有助于估计新病例。这种方法可以补充未来传染病事件的传统流行病学监测，特别是那些潜伏期长且病例数少的疾病。
