Qom University of Medical Sciences Journal

Introduction
Vaccines are one of the most effective medicines to prevent infectious diseases and their complications. Vaccination not only protects the individuals but also the society. Vaccination can reduce the health costs and increase the productivity; it can pave the way for future economic and social development. According to the World Health Organization (WHO), The current vaccine-preventable diseases in children are tuberculosis, polio, diphtheria, tetanus, pertussis, measles, hepatitis B, and haemophilus influenzae type B. Vaccination coverage refers to the percentage of people who have received a vaccine among all people in a certain group who are eligible to receive a vaccine. Information about vaccination coverage provides evidence of success in the immunization program as well as the areas where coverage needs to be improved. For having an effective immunization program, high and appropriate vaccination coverage is necessary. Several studies have been conducted in this case. Considering the increase in the trend of communicable and non-communicable diseases in Iran and its direct impact on the lifestyle and health of people, and given the importance of reducing health costs and reducing the number of unnecessary visits to hospitals and emergency centers by vaccination, and since no comparative study has been conducted on the vaccination coverage for vaccine-preventable diseases based on the WHO indicators in Iran, this study was conducted with the aim of determining the immunization coverage for vaccine-preventable diseases in the last 10 years in Iran compared to the level expected by the WHO.
Methods
This is a systematic review. A structured search was conducted for finding related studies in English or Farsi based on the entry criteria in two national databases (Scientific Information Database (SID) and IranDoc) and four international databases (Web of Science, PubMed, Scopus and Google Scholar) using the keywords “immunization coverage”, BCG vaccine coverage, MMR vaccine coverage, DTP vaccine coverage, polio vaccine coverage, hepatitis B vaccine coverage. The inclusion criteria were: being conducted in Iran from 2011 to 2021 on immunization coverage based on Iran’s routine vaccination program. The exclusion criteria were: Poor quality score based on the STORBE criteria for descriptive studies, sample size <200, and having unclear results.
To select the studies, first their titles were checked in terms of relevance. Then, the abstracts of articles were evaluated in the next step in terms of relevance to the study purpose. The selected cases were finally noted. Their various information including author (s), study purpose, study area, sample size, sampling method, type of study, study variables, effective variables, and immunization coverage for each vaccine were recorded. Their findings were summarized and the data were analyzed by the content analysis.
Results
Initial search yielded 148 articles. After removing the duplicates, 68 articles remained. After screening them based on the inclusion criteria, finally 7 eligible articles were selected for the systematic review. Of 7 studies, two studies were conducted in Tehran province, one in Kermanshah province, one in Fars province, one in the southeast of Iran, and two in the entire country. Among the studied studies, one study was a systematic review, five studies were descriptive cross-sectional , and one study was a documentary study. The results of the studies showed that the lowest overall immunization coverage was 96.8% and the highest overall immunization coverage was 98.6%. Except for the measles-mumps-rubella vaccine whose coverage was 84.7%, the coverage of all types of vaccines was above 90%. The WHO plan is to achieve over 90% coverage for all vaccines by 2030.
Not knowing the vaccination time, sickness of children, and difficulty traveling outside the city were the main reasons for not vaccinating children. Moreover, several factors including differences in gender, nationality, ethnicity, the existence of vulnerable groups in different regions of the country, even in the big cities, affected the immunization coverage and the equal distribution of vaccines in different regions and were major challenges in vaccination in Iran. The complications of the vaccines and the simultaneity of some of these complications caused a decrease in immunization coverage.
Discussion
Immunization coverage for vaccine-preventable diseases in Iran is optimal and even higher than the recommendation level of WHO. Currently, the immunization coverage in Iran is within the scope of the goals set in the Immunization Agenda 2030. However, paying attention to the factors affecting the vaccination process and removing the barriers to achieving full immunization coverage in Iran are necessary for maintaining the current immunization coverage and improving the health system for vaccine-preventable diseases.
Ethical Considerations
Compliance with ethical guidelines
This Study protocol is approved by ethical committee of Qom University of Medical Sciences.
Funding
Vice chancellor of Qom University of Medical Sciences financially support this works.
Authors contributions
All authors works equally in all part of this work.
Conflicts of interest
According to the authors of this article, there is no conflict of interest.
Acknowledgements
We are very thankful for Qom University of Medical Sciences due to supporting this work.