Spatial distribution of vaccine-preventable diseases in central Iran in 2015-2018: A GIS-based study.

Vaccination is the second most effective health measure to maintain public health and prevent diseases after providing safe drinking water. This study aimed to determine the geographical distribution of vaccine-preventable diseases (VPDs) in Qom Province in four years (2015-2018) using Geographic Information System (GIS). In this cross-sectional study, the indicators of VPDs surveillance were extracted from the VPDs surveillance system at the Centers for Disease Control and Prevention (CDC) in Qom University of Medical Sciences. They were further evaluated, and the incidences of VPDs in the study years were investigated. Finally, the spatial distribution map of VPDs was provided for surveillance quality in each Qom district by Arc GIS 10.3 software. The annual incidence rate (AIR) was estimated to be 18.47 for hepatitis B, 0.29 for measles, 0.13 for rubella, 0.09 for pertussis, 0.29 for diphtheria and 0.91 for acute flaccid paralysis (AFP). The highest incidences of AFP, rubella and measles were observed in Markazi district. Salafchegan was a district with the highest incidence of diphtheria, and the highest incidence rate of hepatitis B was observed in Khalajestan district. In addition, all pertussis cases were reported from Qom city. According to thematic maps of GIS, the annual incidence rate of VPDs in Qom Province was lower than the mean rate in Iran. Nevertheless, it is highly recommended that a high immunization coverage should be done in the childhood and good surveillance indicators such as non-disease discarded rate, and the proportion of suspected cases with an adequate investigation should be used to monitor VPDs.