Iranian Journal of

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Background & Objectives: Pediculosis is a ubiquitous and contagious parasitic dermatosis. Throughout the world, infestation by the head louse (Pediculus humanus capitis) is more common among schoolchildren, especially in those aged 6-11 years. This descriptive/analytical study was carried out in 2003 to determine the prevalence of pediculosis capitis and risk factors involved in the epidemiology of pediculosis in primary school pupils in Amlash, Gilan province.
Methods: The children were selected by cluster random sampling of schools and classes, and then examined for head lice using hair conditioners and a fine-toothed head lice comb. We screened a total of 4244 pupils from 95 primary schools. We used a comprehensive questionnaire to evaluate the effects of school type and location, education level, parent job, regular baths, number of persons sharing the same bed, combing frequency, host sensitivity, family size, hairstyle, gender, and hair length.
Results: Statistical analysis using χ2 tests showed that school type, school location, parent job, regular baths, number of person who share the same bed, frequency of combing, gender, host sensitivity, family size, and hairstyle are significantly associated with infestation. Infestation rate showed no correlations with hair color, season, age, or education level. Results showed that pediculosis is more prevalent in rural than in urban areas. The average rate of infestation for the area was 9.2%, indicating an epidemic situation by standard criteria.
Conclusions: The high prevalence of P. capitis infestation among these children was probably due to poor environmental hygiene and scarcity of water. Hygienic controls of schoolchildren by nurses are important for elimination of Pediculus humanus capitis. This is the first community-based study describing in detail the epidemiology of head louse infestation in the Amlash district of Gilan province in Iran and confirms that Pediculosis capitis is still a problem in many environments, particularly those with low life standards and poor health care.

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Background & Objectives: Early detection can improve the outcome of visual impairment in children, and one method for early detection could be screening of pre-school children with visual acuity tests. The aim of this study was to determine the validity of these tests when they are used on children entering grade school.
Methods: For this cross-sectional study we drew 39 random clusters, comprising a total of 5721 school children. We then used 2158 student files to extract data on tests of vision performed by school health officers and compared these data with data generated by optometrists. Measurement of uncorrected visual acuity was done with the E Chart by both teachers and optometrists.
Results: The sensitivity and specificity of teacher-administered tests were 25.0% and 96.6%, yielding positive and negative predictive values of 13.4% and 98.4%, respectively. Sensitivity and specificity rates did not show any significant difference between male and female populations (P=0.356, P=0.258), but the difference between specificity in urban and rural areas was significant (P<0.001).
Conclusions: Screening tests for visual impairment did not attain the desired level of sensitivity or specificity for case detection in school children. More accurate procedures are required to minimize the number of false negative results.

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Background & Objectives: To determine the risk factors for acute diarrhea disease in children.
Methods: This study involved 220 cases and 220 controls in Dr. Sheykh Hospital, a specialzed pediatric hospital in Mashhad. Cases were children seen in the emergency department with loose watery feces, diagnosed as acute diarrhea by the physician. The controls were selected from the same setting as the cases and included children with traumas, burns, acute respiratory complaints and other diseases.
Results: In univariate logistic regression, variables having a significant relationship with acute diarrhea disease included formula feeding in the first 6 months of life, antibiotic therapy over the preceding 15 days, mother's employment, mother's acquaintance with oral rehydration solutions, place of residence, and disruption in the water supply in the week before illness. We performed multiple logistic regression to examine the role of these variables as independent risk factors for acute diarrhea. Use of formulas before 6 months of age (OR=3.21, 95%CI: 1.77-5.79), and type of residence (OR=1.83, 95%CI: 1.24-2.71), and mother's employment (OR=2.48, 95%CI: 1.2-5.06) were the factors that remained in the multiple logistic model and had a significant relationship with the disease.
Conclusions: This study identified some environmental risk factors for acute diarrhea disease. High-risk groups and mothers of children under 5 years of age should be aware of these risk factors in order to prevent disease in their children. Prevention of acute diarrhea in children can significantly reduce the current burden on the health system.

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Background & Objective: Malnutrition is one of the main nutritional problems among children under 5 years especially in developing countries. The effects of malnutrition in this range of age group includes disorder of mental and physical growth and development, increase in the morbidity and mortality, decrease of the learning capacity. A detailed epidemiological picture of the prevalent malnutrition status among children under 5 years in different regions of Iran enables health policy makers to identify priorities, establish political commitment and design appropriate interventional programs to prevent and control malnutrition and improve nutritional status of children. To determine the prevalence rate of malnutrition among children under 5 years.
Methods: Demographic data, weight and height of 34200 Iranian children between 0-72 months old in 28 provinces of the country in 2005 year based on a cluster sampling were gathered. The subjects' weight and height were measured by trained staff. Prevalence of underweight, stunting, and wasting indicators was determined by measuring the weight and height of subjects in urban and rural areas. EPI6 statistical software, version b6/04, was used for all statistical analyses.
Results: 4.7% of the children aged less than five years suffered from stunting (95% CI: 4.5- 4.9%) The prevalence of this type of malnutrition among urban children is significantly less than rural children (95% CI: 3.1- 3.5% and 6.5-7.1% respectively). Meanwhile the prevalence of underweight was 5.2% in the country (95% CI: 5.1-5.4% while the prevalence of this type of malnutrition was significantly less among urban children than those in rural ones. Moreover, the prevalence of wasting was 3.7% (95%CI: 3.5-3.9%) and there was a significant difference in this regard between the urban and rural children. Thus this indicator was significantly higher among urban children than those in rural areas (95%CI: 3.8-4.3% and 3.0-3.5% respectively).
Conclusion: The results of the study show that the prevalence of protein-energy malnutrition was low among Iranian children under five years old. In comparison with previous studies, it is felt that there has been a prudent decrease in all malnutrition in all levels. However, there were significant differences in the prevalence of malnutrition in different provinces, which has resulted in the differences in their developmental stages as well. It appears that subjective strategies are required to improve the nutritional and health status among children under five in all provinces.

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Background & Objectives: Children are highly vulnerable to TB and childhood tuberculosis is a sign of TB transmission in community. This study aimed to determine the epidemiologic trend of this disease in Iranian children.
Method: A Trend Study was conducted to evaluate all Iranian patients aged below 14 who had been diagnosed with pulmonary or extrapulmonary TB from 1992 to 2005. Statistical relationships were tested using chi square tests (c²) and the software package SPSS (version 11.5).
Results: Out of the 6168 cases studied, 2528 (40.1%) were boys. Patients were assigned to three groups based on disease type: there were 1812 (29.4%) sputum- positive, 1920 (31.1%) sputum-negative, and 2449(39.7%) extrapulmonary cases.The incidence of sputum-positive TB declined from 0.8 per 100000 in 1992 to 0.2 per 100000 in 2005. A similar declining trend was observed for the overall TB incidence and in the incidence of sputum-negative and extrapulmonary cases. There was significant difference in TB incidence between girls and boys in the 10-14 year age group (P<0.001), but no sex difference was observed in 0-4y and 5-9y age groups.
Discussion: The incidence of sputum-positive TB decreased by 75 percent over the study period. This could be partly due to improvements in health status, better disease knowledge and the effects of Iran's National TB Control Program.
Conclusions: In children aged below 10 years, there was no significant difference in the incidence of tuberculosis between girls and boys. At puberty, the incidence of all types of TB was higher in girls. Based on these findings, further studies are needed to elucidate the gender distribution of childhood tuberculosis in Iran.

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Background & Objective: High prevalence of malnutrition and its relation with mental and physical health of children is one of the important health problems in developing countries. The aim of this survey was to assess the nutritional status and related factors in 0-24 month-old children in South Khorasan province in Iran 2006.
Methods: Seven hundred children of 0-24 month-old in South Khorasan province were included in this survey. A designed questionnaires and face-to-face interview with the mothers were used in order to obtain the required information . In addition, weight (Wt) and height (Ht) of the children were measured and compared with standard charts issued by the American National Center for Health Statistics (NCHS). The nutritional status was determined based on weight for age (Wt/A), height for age (Ht/A), and weight for height (Wt/Ht) indices.
Results: Mean of children's age was 11.1 ± 7.8 month. Based on the Z-score, cut-off point under -2SD from median of the reference population (NCHS), 10.6% of the children were underweight (Wt/A), 5.3% stunted (Ht/A) and 11.6% wasted (Wt/Ht). A statistically significant relationship was found between indices of malnutrition and age and breastfeeding status of children. There was no association between gender and residence of children with their nutritional status.
Conclusion: With regard to prevalence of malnutrition in children, breastfeeding is highly recommended.

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Background & objectives: statistical modeling explicates the observed changes in data by means of mathematics equations. In cases that dependent variable is count, Poisson model is applied. If Poisson model is not applicable in a specific situation, it is better to apply the generalized Poisson model. So, our emphasis in this study is to notice the data structure, introducing the generalized Poisson regression model and its application in estimates of effective factors coefficients on the number of children and comparing it with Poisson regression model results.
Methods: Besides introducing Poisson regression model, we introduced its application in fertility data analysis. A sample of 1019 women in rural areas of Fars was selected by cross sectional and stratified sampling methods. The number of children of family was determined as a count response variable for model validation.
Results: The sample mean and sample variance of the response variable Y, the number of children, are respectively 4.3 and 8.3 (over-dispersion). Log-likelihood was -1950.93 for Poisson regression and -1946.93 for generalized Poisson regression model.
Conclusions: The results revealed that this data have over-dispersion. According to selection criteria, the suitable model for this data analysis was generalized Poisson regression model. It can estimate effective factors coefficients on the number of children exactly.

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Background & Objective: Refractive errors (myopia, hyperopia and astigmatism) could lead to an impaired quality of life affect a large proportion of the population worldwide, irrespective of age, sex and ethnic group. Such refractive errors can be easily diagnosed, measured and corrected with spectacles or other refractive corrections to attain normal vision. Since there is paucity of information in school children in Iran we aimed to investigate the distribution pattern of refractive status and prevalence of refractive errors in school-age children in Shiraz
Methods: A random sampling strategy in geographically defined clusters was used to identify children aged 6-15 years in Shiraz between 2008-2209. We carried out a school survey and actual eye examinations, including visual acuity measurements, stereopsis examination, anterior segment and eyeball movements, fundus examinations, and cycloplegic retinoscopy with 1% cyclopentolate.
Results: Of 3065 selected individuals, 2683 were participated in the study (response rate 86.6%). According to cycloplegic refraction, 4.85% (95% (Cl), 3.52 to 6.16) of the primary and middle school students were myopic and 4.64% (95% Cl, 3.52 to 6.19) were hyperopic. For high school students, these rates were 22.19 and 11.4% respectively. Myopia and hyperopia were shown to be correlated with age. Prevalence of anisometropia, amblyopia and strabismus were 2.51%, 2.31(95%CI 1.51-3.11) and 1.83% (95%CI 1.15-2.50).
Conclusion: Compared to other published reports, the rate of myopia in the school children of Shiraz seems relatively high.

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Background & Objectives: Increasing in prevalence of juvenile myopia in recent decades in eastern and western countries, especially in urban elementary school children, suggests that changing in early life style may play an important role in development of myopia. Our aim was to determine the relationships between myopia and overweight in elementary school children of Eslamshahr a city near Tehran, Iran Methods: In a case control study, 240 new myopic primary school children (grade 2-4) identified as cases and 240 children without myopia in the same schools enrolled as control group. Anthropometric information was completed from schools’. Other information about pre-entrancing to school was collected by interviewing their parents. Children having a Body mass index BMI>=85th CDC2000 percentile were identified as overweight. Adjusted odds ratio for overweight was estimated after adjusting other potential risk factors.
Results: Of total 53.3% were girls. 23.8% of children in case group and 10.1% of them in control group were categorized in overweight group. After adjusting for other potential risk factors (family history, breast milk intake, near works, mother`s job and financial position) being overweight was independently associated to myopia (OR: 3.10, 95% CI: 1.9-5.03).
Conclusion: It is concluded that overweight in children in preschool age, is independently associated with increased risk of myopia in primary school children. Therefore health promotion programs in order to change of the life style in this group of children should be considered.

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Background & Objectives: Cutaneous leishmaniasis (CL) is one the major health problem in tropical and sub– tropical countries. Bam district in Iran is an old focus of anthroponotic CL (ACL). The aim of this survey was to assess the prevalence rate of CL by case– finding, treatment of cases and training of primary school children in the city and suburb of Bam in 2010.

Methods: All school children in three levels (18501 children) were included. Children were physically examined for presence of sores or scars. Suspected cases were referred to the center for cutaneous leishmaniasis control (CCLC) for diagnosis and the CL positive children were treated, accordingly. School children were trained and also educational and informative pamphlets were given to their parents.

Results: After initial physical examination ,117 suspected school children (6.9%) were referred to the CCLC and 48 children (28 per 10000) diagnosed as CL patients, comprising of 19 females (39.5%) and 29 males (60.5%). Fifteen (31.2%) school children were identified as lupoid leishmaniasis, failure to treatment or non – healing cases.

Conclusion: The prevalence rate was decreased about 18– fold as compared to the previous investigation in 2005. Establishment of the CCLC, active case– finding and subsequent treatment, seem to be a successful model for controlling CL in the endemic countries.

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Background & Objectives: Food insecurity has been a global concern. The purpose of the present study was to examine the relationship between household food insecurity and depression in mothers with school children in Ray city.

Methods: A cross-sectional survey of 430 mothers of school children was conducted in 2010 in Ray city. We employed USDA food security questionnaire. The prevalence of depression in mothers was assessed by Beck Depression Inventory (DBI).
Results: Household food insecurity was identified approximately in fifty percent of participants and frequency of depression was 51.4% in mothers. Depression in ‘food secure' group was 34.6%, and in ‘food insecure with hunger' group was 77.8%. There was a positive relationship between depression and food insecurity in mothers having primary school children living in Ray.
Conclusion: The findings of this study revealed that level of food insecurity among mothers seems high. This study highlights the need to integrate programs addressing food insecurity and poor mental health for mothers.

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Background & Objectives: Convulsion is the most common pediatric neurological problem that requires special attention in this group. The purpose of this study was to determine the frequency of seizures and to evaluate its risk factors in children in Bandar Abbas, Iran
Methods: A retrospective study was conducted on 222 children with seizures admitted to children hospital during 2008.
Results: Of total children hospitalized due to seizure, 64.5% were male with age range 1-2 years. Fever was the most cause of seizure. In 58.8% of cases, the child's age at the time of first convulsion was 1-3 years. The seizure attack occurred in wake up in 63.8% of cases, and 65.8% of the samples had normal consciousness at the time of admission. The mean duration of seizure in 64.1% of cases was less than 5 minutes and type of seizure in 80.1% has been reported as generalized tonic colonic. A history of convulsion in other family members was reported in 28.9% and in 19.36%, there was close family relationship between parents. There was no significant relationship between type of delivery, gestational age and birth weight with type and duration of seizure (P>0.05).
Conclusion: Particular attention should be paid to children with seizure during history-taking and be more vigilant to high-risk patients and those who might need prophylactic anticonvulsants.

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Background & Objectives: Asthma and allergic diseases remain among the most important health problem in different societies that affect childhood life. These diseases mostly seem to be occurred in children with family history positive. In this study, we aimed to evaluate the association between family history and the prevalence of allergic diseases in children in Gonabad.
Methods: A cross-sectional study was conducted in the city of Gonabad in 2011 year. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire were completed by 1627 students whom were selected by using multi-level sampling across city. The Chi-Square test was used for comparison of qualitative variables between two groups and Odds ratios (ORs) and 95% confidence intervals (CI) were calculated.
Results: Of the total (1627) participated students, 876 (53.8%) were boys and 751 (46.2%) were girls. Mean age of children was 14.5±1.8. Almost forty percent of children had at least one allergic symptom at sometime in their life and 48/1% had family history and 35/1% did not have family history (P<0.001). However, lifetime and 12-month prevalence of rhinitis symptoms, 12-month prevalence of rhino conjunctivitis and lifetime hay fever and eczema was significantly higher in students with positive family history than those with negative family history (P<0.05).
 Conclusion: Our study shows that the prevalence of most allergic disorders was higher in children with positive family history. It seems that heredity plays a major role in the occurrence of allergic diseases in children.

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Background & Objectives: The aim of this study was to investigate the trend of mortality of children under five years old in Kurdistan Province during 2007 to 2011.

Methods: The data of this descriptive-analytical study on deaths and births was collected from provincial deaths registry system and Civil Registration System during 2007 to 2011. The main indicators including under-five mortality, infant mortality, and neonatal mortality rate during the given period were studied. The relationship between variables was calculated using chi-square test.

Results: The neonatal mortality rate changed from 13.5 per thousand live births in 2007 to 12.2 per thousand live births in 2011. During the same period of time, the infant mortality rate and under-five mortality rate declined from 17.1 and 20.2 to 14.9 and 17.4 per thousand live births, respectively. A significant relationship was found between gender and infant mortality. Among the major causes of mortality, prenatal diseases, especially infant diseases, were the most common cause of death in the neonatal period.

Conclusion: According to the results of this study, although there was a reduction in the under-five mortality rate during these years, the observed decline, especially the decline in infant mortality rate, was very slow. There are still some preventable causes of death in children which require more attention by the health system and researchers

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  Background & Objectives : Migraine is the most common type of headache in children. Over 30% of patients have disabilities, so early detection and timely treatment is necessary to prevent attacks, increase learning, and prevent absenteeism. The aim of the study was to determine the prevalence of migraine in children.

  Methods: In this cross - sectional study with two-stage stratified random cluster sampling the International Headache Society (IHS) for migraine diagnosis and (PedMIDAS) questionnaire were completed through interviews with the students’ parents. Data was analyzed with SPSS software and chi-square test.

  Results : Of 1117 children with a mean age of 41.1 ± 9 years, 551 (49.3) were female and 556 (50.7) were male of whom 185 (56.16%) had a headache and 40 (2.16%) had migraine. Most of the time, the pain started on the first day of the week with a moderate intensity. Aggravating factors were physical activity and stress, and alleviating factors were sleeping and resting. The pain was bilateral and was accompanied by nausea and vomiting. The mean number of headache attacks in the past three months was 8.85± 7.65 which lasted for a mean duration of 6.38 ± 8.02 hours with a mean interval of 24.70± 26.21days.

  The frequency of migraine in children by age and sex were not significantly different. More than of the children had a positive family history but were not visited by the doctor. About 79.37% of the students had first degree disability, %54.10 had second degree disability, %9.05 had third degree disability, and % 1.04 had fourth degree disability.

  Conclusion: Given the increasing prevalence of migraine with age and the risk of chronic diseases and individual and social impairment, it is important to prevent headache attacks through early identification and moderation of the aggravating factors and education of non-medical preventive methods.

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  Background & Objectives : The identification of risk factors and their interactions is important in medical studies. The aim of this study was to identify the interaction of risk factors of cerebral palsy in 1-6 years-old children with classification regression methods.

  Methods : The data of this cross-sectional study which was conducted on 225 children aged 1-6 years was collected during 2008- 2009. Classification regression methods (classification and regression tree (CART), adapting boosting (AdaBoost), bagging, and C4.5 algorithm) were used to identify interactions between risk factors. Data analysis was carried out with R3.0.1 software.

  Results : The identified interactions of the factors by a) the AdaBoost method were (consanguinity: sex, previous pregnancies: vaginal delivery, consanguinity: sex: preterm, history of the disease: preterm: asphyxia, consanguinity: sex: asphyxia, history of the disease: sex: small size relative to gestational age, neonatal infection: asphyxia: small size relative to gestational age, history of the disease: sex: asphyxia, preterm: asphyxia: vaginal delivery) by b) the bagging method were (consanguinity: asphyxia, consanguinity: preterm: asphyxia), by c) the C4.5 algorithm were (asphyxia: preterm, asphyxia: consanguinity: history of the disease: preterm), and by d) the CART method were (asphyxia: consanguinity). The sensitivity and specificity of the AdaBoost method was better than other methods (0.941±0.029 and 0.951±0.030, respectively).

  Conclusion : The AdaBoost method could better recognize and model potential interactions between risk factors of cerebral palsy.

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  Background & Objectives : Children who work or live on the street are one of key populations at risk for HIV and hard to reach for study or providing services. Here, as a methodological paper, we present the methods and steps of a rapid assessment and response (RARE) project conducted among street children in Tehran.

  Methods : We applied a mixture of qualitative (literature review, focus group discussion, in-depth interview) and quantitative (structure interview) methods to collect data from key informants in non-governmental and governmental agencies as well as street children. We applied targeted sampling to recruit key informants and time location sampling to recruit street children.

 Results: The study was conducted in eight steps to recognize the involved stakeholders, define target population (street children) and to guide on how to approach them (steps 1 to 2: Initial Consultation, Study Area Profile), to map the venues and gathering spots and ethnographic findings crucial for further recruitment into surveys (steps 3 to 5: Contextual Assessment, Population and Setting Assessment, Health Issues Assessment), assess the risk behaviors (step 6: Assessment Behavior Risk and Health), evaluate the response (step 7: Intervention Assessment), and develop an operational plan for improving the services (step 8: Developing an Action Plan).

  Conclusion: RARE is a participatory mix research method with sufficient flexibility to study complex health problems such as stigmatized HIV risk behaviors among high risk and hard to reach populations and also to assess the health sector response.

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Background and Objectives: Disorders of height and weight growth are the most important health disorders affecting children younger than two in developing societies. Failure to treat these disorders can lead to the increased mortality and mental, emotional or physical disability. The objective of this study was to investigate the growth trends of children and the factors affecting it.

Methods: This retrospective cohort study was conducted on 2030 children younger than two in Khorramabad, Iran who were selected using stratified and cluster sampling. Based on household records, the weight growth trend was recorded as a four-level variable (decline, stagnation, slowness and desirable) and the the height growth trend was recorded as a three-level variable (stagnation, slowness and desirable); finally, the data were modeled using a longitudinal marginal model and the SAS software version 9.2.

Results: The incidence of at least one decline in the weight growth curve and one stagnation in the height growth curve was 14.2% and 10.4%, respectively. The child’s age and the maternal educational level had a significant effect on the growth trends. However, the sex, parity and the exclusive breastfeeding during the first six months had no significant relationship with the growth trends.

Conclusion: Given the results and the relatively high prevalence of growth disorders among children, it seems that increasing the awareness of low literate women about feeding of the children is the most important approach to manage growth disorders. Additionally, health-care professionals should mostly focus on monitoring the growth of children older than 12 months.

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Background and Objectives: Children immunization program is one of the most successful and most cost-effective public health interventions and medical programs. The study was designed and conducted in order to assess the vaccination coverage in areas covered by Tehran University of Medical Sciences (TUMS).

Methods: This study was a cross-sectional study of children aged 24 months to 6 years living in urban areas and high-risk and marginal areas covered by TUMS. Six hundred and thirty children were sampled in 90 clusters in urban areas and cluster sampling as probability proportional to size sampling was performed in high risk areas and a sample size of 768 children was determined. The questionnaires were completed by interview.

Results: In high risk 750 children (97.7%, 95% CI: 96.32-98.60%) and 616 children (97.8%, 95% CI: 96.3-98.78%) in urban areas had complete immunization histories. Furthermore, 98.4% of the Iranian children and 95.0% of foreign children (P=0.019) in marginal areas and 98.1% of the Iranian children and 92.1% of the foreign children (P=0.046) in urban areas had complete immunization histories.Ignorance of immunization program (%50) was addressed as the main reason for incomplete immunization.

Conclusion: Universal mass vaccination coverage of the children and equal coverage in marginal and urban areas indicated the success of the authorities in the implementation of this program. Organizing training courses for mothers on the immunization program, providing the required facilities and services, monitoring and supervision of vaccination and also considering the immunization status of foreign children seem to be essential in maintaining and improving the existing status.

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Background and Objectives: The Haemophilus influenzae (Hib) conjugate vaccine (HibCV) using a pentavalent formulation was introduced to the Iranian routine immunization program from November 2014. Iran is preparing to include Pneumococcal conjugate vaccines (PCV), as well. Measuring and monitoring the impact of HibCV and PCV are necessary to provide evidence for introduction and sustained administration of this vaccine.

Methods: We addressed the possibility of implementing the "3-tiered approach to IB VPD surveillance" as proposed by the World Health Organization using a feasibility study. Expert opinions were asked to address published literature regarding the study design and methods of measuring the impact of newly introduced vaccines.

Results: There are different methods and study designs to measure the impact of new vaccines, including population based active surveillance systems and vaccine effectiveness studies. The results of the feasibility study and expert opinions highlighted the superiority of a sentinel hospital-based surveillance system in Iran.

Conclusion: It is necessary to conduct some systematic reviews and meta-analyses to provide evidence for the trend of Hib and Streptococcus pneumonia related diseases, i.e. invasive bacterial diseases including meningitis, pneumonia, and sepsis. To monitor indirect effects of the PCV vaccine, implementing periodic surveys on the prevalence of nasopharyngeal carriers are recommended.