Alarm Thresholds for Pertussis Outbreaks in Iran: National Data Analysis
10.24171/j.phrp.2020.11.5.07
- Author:
Yousef ALIMOHAMADI
1
;
Seyed Mohsen ZAHRAEI
;
Manoochehr KARAMI
;
Mehdi YASERI
;
Mojtaba LOTFIZAD
;
Kourosh HOLAKOUIE-NAIENI
Author Information
1. Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Publication Type:Original Article
- From:
Osong Public Health and Research Perspectives
2020;11(5):309-318
- CountryRepublic of Korea
-
Abstract:
Objectives:The purpose of the current study was to determine the upper threshold number of cases for which pertussis infection would reach an outbreak level nationally in Iran.
Methods:Data on suspected cases of pertussis from the 25th February 2012 to the 23rd March 2018 from the Center for Disease Control and Prevention in Iran was used. The national upper threshold level was estimated using the exponentially weighted moving average (EWMA) method and the Poisson regression method.
Results:In total, 2,577 (33.6%) and 1,714 (22.3%) cases were reported in the Spring and Summer respectively. There were 1,417 (18.5%) and 1,971 (25.6%) cases reported in the Autumn and Winter, respectively. The overall upper threshold using the EWMA and the Poisson regression methods, was estimated as a daily occurrence of 8 (7.55) and 7.50 (4.48-11.06) suspected cases per 10,000,000 people, respectively. The daily seasonal thresholds estimated by the EWMA and the Poisson regression methods were 10, 7, 6, 8 cases and 10, 7, 7, 9 cases for the Spring, Summer, Autumn, and Winter, respectively.
Conclusion:The overall and seasonal estimated thresholds by the 2 methods were similar. Therefore, the estimated thresholds of 6-10 cases in a day, per 10,000,000 people could be used to detect pertussis outbreaks and epidemics by health policymakers.
