Abstract：
BACKGROUND: In 2020, the Council of State and Territorial Epidemiologists (CSTE) pertussis case definition was modified; the main change was classifying polymerase chain reaction (PCR)-positive cases as confirmed, regardless of cough duration. Pertussis data reported through Enhanced Pertussis Surveillance (EPS) in 7 sites and the National Notifiable Diseases Surveillance System (NNDSS) were used to evaluate the impact of the new case definition.
METHODS: We compared the number of EPS cases with cough onset in 2020 to the number that would have been reported based on the prior (2014) CSTE case definition. To assess the impact of the change nationally, the proportion of EPS cases newly reportable under the 2020 CSTE case definition was applied to 2020 NNDSS data to estimate how many additional cases were captured nationally.
RESULTS: Among 442 confirmed and probable cases reported to EPS states in 2020, 42 (9.5%) were newly reportable according to the 2020 case definition. Applying this proportion to the 6124 confirmed and probable cases reported nationally in 2020, we estimated that the new definition added 582 cases. Had the case definition not changed, reported cases in 2020 would have decreased by 70% from 2019; the observed decrease was 67%.
CONCLUSIONS: Despite a substantial decrease in reported pertussis cases in the setting of coronavirus disease 2019 (COVID-19), our data show that the 2020 pertussis case definition change resulted in additional case reporting compared with the previous case definition, providing greater opportunities for public health interventions such as prophylaxis of close contacts.
METHODS: We compared the number of EPS cases with cough onset in 2020 to the number that would have been reported based on the prior (2014) CSTE case definition. To assess the impact of the change nationally, the proportion of EPS cases newly reportable under the 2020 CSTE case definition was applied to 2020 NNDSS data to estimate how many additional cases were captured nationally.
RESULTS: Among 442 confirmed and probable cases reported to EPS states in 2020, 42 (9.5%) were newly reportable according to the 2020 case definition. Applying this proportion to the 6124 confirmed and probable cases reported nationally in 2020, we estimated that the new definition added 582 cases. Had the case definition not changed, reported cases in 2020 would have decreased by 70% from 2019; the observed decrease was 67%.
CONCLUSIONS: Despite a substantial decrease in reported pertussis cases in the setting of coronavirus disease 2019 (COVID-19), our data show that the 2020 pertussis case definition change resulted in additional case reporting compared with the previous case definition, providing greater opportunities for public health interventions such as prophylaxis of close contacts.
摘要：
背景：2020年，国家和领土流行病学家委员会（CSTE）百日咳病例定义进行了修改；主要变化是将PCR阳性病例分类为已确认，无论咳嗽持续时间。通过七个地点的增强百日咳监测（EPS）和国家法定疾病监测系统（NNDSS）报告的百日咳数据用于评估新病例定义的影响。
方法：我们比较了2020年咳嗽发作的EPS病例数与根据先前（2014年）CSTE病例定义报告的病例数。为了在全国范围内评估变化的影响，根据2020年CSTE病例定义新报告的EPS病例比例应用于2020年NNDSS数据,以估计全国新增病例数.
结果：根据2020年病例定义，在2020年报告给EPS的442例确诊和可能病例中，有42例（9.5％）是新报告病例。将这一比例应用于2020年全国报告的6124例确诊和可能病例，我们估计新定义增加了582例。如果案例定义没有改变，2020年报告的病例将比2019年减少70%；观察到的减少是67%。
结论：尽管在COVID-19病例中报告的百日咳病例大幅减少，但我们的数据显示，与以前的病例定义相比，2020年百日咳病例定义的改变导致了额外的病例报告，为公共卫生干预措施提供更多机会，例如预防密切接触者。
方法：我们比较了2020年咳嗽发作的EPS病例数与根据先前（2014年）CSTE病例定义报告的病例数。为了在全国范围内评估变化的影响，根据2020年CSTE病例定义新报告的EPS病例比例应用于2020年NNDSS数据,以估计全国新增病例数.
结果：根据2020年病例定义，在2020年报告给EPS的442例确诊和可能病例中，有42例（9.5％）是新报告病例。将这一比例应用于2020年全国报告的6124例确诊和可能病例，我们估计新定义增加了582例。如果案例定义没有改变，2020年报告的病例将比2019年减少70%；观察到的减少是67%。
结论：尽管在COVID-19病例中报告的百日咳病例大幅减少，但我们的数据显示，与以前的病例定义相比，2020年百日咳病例定义的改变导致了额外的病例报告，为公共卫生干预措施提供更多机会，例如预防密切接触者。
