Monitoring progress towards the elimination of measles in Iran: supporting evidence from 2014 to 2016 by application of measles outbreaks data.

BACKGROUND: To achieve the goal of measles eradication, all WHO member countries should continuously monitor the status of measles elimination. This work aims to characterize measles outbreaks in Iran from 2014 to 2016 and calculate the effective reproduction number, given that the country has recently eliminated measles. METHODS: Effective Reproduction Number (R) was estimated to achieve the goal of measles elimination using measles related outbreaks data and epidemiological data from the cases linked to imported cases. Three methods were used to estimate R includes (i) proportion of cases imported, (ii) distribution of outbreak size and (iii) distribution of outbreak generations. RESULTS: Of the 153 outbreaks occurring during the three years of the study, 29 outbreaks (19%) were unknown source, 86% of them were single cases. Estimates of R during the study period by proportion of cases imported were 0.79 (95% CI: 0.73-0.86). Corresponding values for distribution of outbreak size and distribution of outbreak generations methods were R = 0.83 (95% CI: 0.68-0.97) and R = 0.76 (95% CI: 0.54-0.90), respectively. CONCLUSIONS: Estimated values of R represent the important achievement that the outbreaks of measles originating from the indigenous genotype in Iran have been eliminated. Moreover, Iran has also achieved the goal of measles elimination by end of 2015.

Documentation of Measles Elimination in Iran: Evidences from 2012 to 2014.

BACKGROUND: Documentation of achieving the goal of measles elimination to justify to international organizations including the WHO is a priority for public health authorities. This study aimed to address the status of Iran in the achievement of the measles elimination goal from 2012-2014. STUDY DESIGN: A descriptive study METHODS: Data on the measles outbreaks were extracted from the national notifiable measles surveillance system in Iran from 2012 to 2014. The required documents regarding the achievement of measles elimination, including Effective Reproduction Number (R) and the distribution of outbreak size, was addressed. The R was calculated using the proportion of imported cases as 1 - P, where P is equal to the proportion of cases that were imported. The distribution of the measles outbreaks size was described using descriptive statistics to show their magnitudes. The proportion of large outbreaks with more than 10 cases was considered as a proxy of the R value. RESULTS: The total number of measles cases was 232 cases (including 186 outbreak related cases) in 2012 and 142 cases in 2014, including108 outbreak related cases. The distribution of the measles outbreak size of occurred outbreaks from that period indicated that there were 37 outbreaks with three or more than three cases. The R value in 2012 was 0.87 and the corresponding value for 2014 was 0.76. CONCLUSIONS: According to the magnitude of effective reproduction number and distribution of outbreaks' size, measles has been eliminated in Iran. However, it is necessary to consider the potential endemic activity of measles because of no authorized immigration.