This assessment was conducted in Iran, encompassing 31 provinces and 463 districts, using data on measles indicators across four categories: population immunity, surveillance quality, program performance, and threat assessment. Over the course of the research years, 123 cases of laboratory-confirmed measles were reported among children under 5 years old, 20 cases among children aged 5–15 years, and 19 cases among children over 15 years old. The districts of Chabahar and Mashhad reported the highest and lowest incidence of measles, with rates of 76 and ./6 cases per million people, respectively. The highest and lowest incidences in 2021 were observed in Sistan and Baluchestan province.
Remarkably, all 463 districts in Iran were categorized as low risk, constituting 100% of the districts. Consequently, based on the risk assessment results, Andimeshk in Khuzestan province, Chabahar in Sistan and Baluchistan province, and Bojnurd in North Khorasan province obtained the highest risk scores among the districts in Iran, with scores of 27, 24, and 25, respectively. Based on our analysis of the population immunity indicator, all districts in Iran were classified as low risk. The average coverage for the second dose of measles-containing vaccine (MMR2) and the first dose (MMR1) was consistently 95% or higher each year. For districts with MCV1 coverage percentages below 80%, no deduction was applied, and the risk score for this index was considered zero for all districts.
Supplementary Immunization Activities (SIA) have not been implemented in Iran over the past three years. Following World Health Organization guidelines, countries in the advanced stages of elimination, such as Iran with a measles elimination certificate, receive a risk score of zero for all SIA-related indicators in the Programmatic Impact (PI) score.
Regarding suspected measles cases where vaccine status was unclear and had a history, 31% of the districts received the maximum risk score. Additionally, 320 districts had less than 20% of suspected measles cases with unknown or unvaccinated status compared to suspected measles cases aged 12 months or more (Fig. 1)
. Figure 1 : Spatial distribution of suspected measles cases with unknown or unvaccinated vaccination status in Iran in 2019–2021
The surveillance quality indicator indicates that all districts received the minimum points. Regarding the Non-measles discarded rate (NMDR) item, 34 districts were assigned the maximum risk score, 19 districts received a risk score of 4, and 89% of the districts achieved a risk score of 2 or less, placing them in the low-risk (LR) category. In eight districts (Nemin in Ardabil, Amalesh in Gilan, Kalaleh in Golestan, Abdanan in Ilam, Arzoiyeh in Kerman, Saveh in Markazi, Babolsar in Mazandaran, and Piranshahr in West Azarbaijan), the time interval between the announcement and investigation of measles cases exceeded 48 hours. This delay resulted in a risk score of 4 for each of these districts.
Concerning the time interval from the onset of skin rashes to blood sampling in suspected measles cases, 6% of the districts reported that the sampling occurred more than 28 days apart, except for epidemiological cases. In some provinces, more than one district received a high-risk score in this category. The province with the highest number of districts in this situation was Khuzestan, where four districts (Indika, Hamidiyeh, Handijan, and Karon) had less than 80% compliance with timely sampling. The lowest percentage of sample collection was observed in the districts of Miane in East Azerbaijan province, with a rate of 32%. Based on available information, all provinces in Iran fall into the low-risk domain in the surveillance quality index. The highest risk score (12) was attributed to three districts: Borujen (from four Bakhtiari districts), Andimeshk (Khuzestan), and Bojnord (North Khorasan). The examination of this index considered data from the last year of the research, and in the percentage of suspected measles cases with timely access to laboratory results within 10 days, 96% of the districts achieved the low-risk (LR) level. (Refer to Fig. 2 for additional details).
In terms of program performance and associated indicators, all districts in Iran were classified as low-risk domains. No district in Iran received full risk points for all program performance indicators. According to the results, all districts in Iran exhibited a dropout rate in MCV1-MCV2 and Penta1-MCV1 lower than 10%.
In the MCV1 coverage trend, 295 districts received a risk score of zero, and 36% of them showed a trend of 10% or less decrease compared to the last year of the research. Among the provinces, Khorasan Razavi, Fars, and East Azerbaijan had the highest risk scores of 13, 17, and 11, respectively. Alborz, with one district, displayed the lowest decreasing trend.
Regarding the MCV2 coverage trend, 168 districts had a risk score of 2, and 64% exhibited an increasing or similar coverage trend compared to the last year of the survey. Razavi Khorasan province, with 22 districts, had the highest risk score, while Alborz and Mazandaran provinces, each with one district, obtained the lowest risk score. Over three years, there were 162 confirmed cases of measles, with 76% occurring in the age group of less than five years, and 12% in both the age groups of 5–15 and older than 15 years.. The province of Sistan and Baluchistan, with 60 confirmed cases of measles, had the highest number in the border areas in 2021.