Introduction: Immunization remains an important public health intervention. Morbidity and mortality caused by vaccine-preventable diseases are still high in developing countries. We aimed to assess the immunization coverage among children 12-59 months old attending our pediatric outpatient clinic and determined the impact of socioeconomic status and parental education level on the utilization of immunization services. Materials and Methods: This was a cross-sectional study in under-fives attending the pediatric outpatient clinic over a 1-month period. A questionnaire was used to collect information on demography, immunization, parental occupation and level of education, and reasons for not completing immunization. Results: Of the 223 children enrolled, 121 (54.3%) were male and 102 (45.7%) were female. One hundred three (46.2%) were fully immunized, while 120 (53.8%) were not. More males were fully immunized; however, this was not significant (χ2 = 0.606, P = 0.436). The majority (65%) of the patients belonged to the lower socioeconomic class; socioeconomic status was associated with immunization status (χ2 =10.460, P = 0.005). The level of education of both parents was also significantly associated with immunization status [father (χ2 = 14.134, P = 0.000), mother (χ2 = 21.507, P = 0.000)]. The main reasons for not completing immunization were ignorance of when to go back for the next dose, lack of approval by the father, the child being ill, and the mother traveling with the child. Conclusion: A large proportion of children was not fully immunized. Poor educational and socioeconomic statuses of the parents were some of the major reasons identified. Intensive community sensitization and awareness programs should include both religious and traditional leaders so as to reverse this situation.
Keywords: Immunization, socioeconomic status, under-five
Immunization still remains the most effective, safe, and efficient public health intervention, saving an estimated three million lives from vaccine-preventable diseases, notably diphtheria, pertussis, tetanus, and measles.  The morbidity and mortality caused by these diseases are still very high in many developing countries. Nearly 20% of children do not receive the three life-saving doses of the diphtheria, pertussis, and tetanus (DPT) vaccines.  Approximately 29% of deaths in children under 5 years of age are vaccine-preventable.  In 2011 alone, 1.5 million children died from diseases preventable by currently recommended vaccines. 
Over 70% of children not reached by immunization live in 10 countries, including Nigeria, with polio remaining endemic in three countries (Afghanistan, Nigeria, and Pakistan). 
The under-five mortality rate in Nigeria is one of the highest in the world, and vaccine-preventable diseases are said to be responsible for at least 20% of these deaths. 
According to United Nations Children’s Fund (UNICEF) and World Health Organization (WHO) guidelines, a child should receive a bacillus Calmette-Guιrin (BCG) vaccination to protect against tuberculosis, three doses of DPT to protect against diphtheria, pertusis, and tetanus, three doses of oral polio vaccine (OPV), and a measles vaccination; all by 12 months of age. 
The Multiple Indicator Cluster Survey (MICS) 2007 for Nigeria showed disparities in the coverage of all types or levels of vaccination along rural-urban and North-South parts of Nigeria, and along levels of education and wealth status.  The coverage was found to be low in the rural areas, the northern part of the country, and among children of mothers with no education and children in the poorest wealth quintiles. 
To the best of our knowledge, there has been no published study in Gusau, Zamfara State conducted on the immunization and socioeconomic statuses of children under the age of 5 years. In view of this, we conducted this study to assess immunization coverage among children 12-59 months old attending our pediatric outpatient clinic. We also determined the impact of socioeconomic status of the households and parental education levels on the utilization of immunization services.
The study was conducted at the Yariman Bakura Specialist Hospital, Gusau. It is a specialist hospital of the Zamfara State Government, Nigeria that serves as a secondary and tertiary care center for the state capital, as well as a referral center for all the 14 Local Government Areas of the state.
The study was a descriptive, cross-sectional study among children aged 12-59 months from households at varying socioeconomic levels attending the pediatric outpatient clinic. Children whose parents consented to the study were consecutively enrolled over a 1-month period from June 1-30, 2014.
Data on the immunization status of the children were collected using a structured questionnaire. The immunization status of the children was recorded as completely immunized or not completely immunized. The type and number of each vaccine dose were also registered. Both parents’ educational level and occupation were recorded, and their socioeconomic class was determined using the Olusanya et al.  classification method. In the present study, the level of education was considered as educated if a parent had at least some secondary school education, and as limited if a parent had primary, some primary, or no education, for ease of comparison. The Local Government Area where each child resided was also noted.
Ethical approval for the study was obtained from the Yariman Bakura Specialist Hospital Ethical Committee.
Data were entered into the Statistical Package for Social Sciences version 16 (SPSS Inc, Chicago, IL 60606-6412) for cleaning and analysis using standard methods. Quantitative variables were summarized using mean and standard deviation. Categorical variables were summarized using frequency and percentages. The chi-square test was used for association between categorical variables. A P value of <0.05 was considered statistically significant.
A total of 223 children were enrolled in this study, of whom 121 (54.3%) were male and 102 (45.7%) were female, for a M:F ratio of 1.2:1. The mean age was 27.26 ± 1.25 months.
Only two children seen were not from Zamfara State, as shown in [Table 1], with Gusau Local Government Area, where the hospital is located, having the highest number of children recruited in the study.
All the children had some immunization, with 103 (46.2%) fully immunized and 120 (53.8%) not fully immunized. [Table 2] shows the various vaccinations and the number of children immunized.
Fifty-three (23.8%) of the fully immunized children were male, while 50 (22.4%) were female. Of those not fully immunized, 68 (30.5%) were male, while the remaining 52 (23.3%) were female, as shown in [Figure 1]. There was no statistically significant difference in immunization status between the two sexes (χ2 = 0.606, P = 0.436).
Sixteen (7.2%) scored 2 points, 53 (23.8%) scored 3 points, while 77 (34.5%) and 77 (34.5%) scored 4 and 5 points, respectively. The majority of the children belonged to the lower socioeconomic class, as shown in [Figure 2].
Children from a higher social class were more likely to be fully immunized than those from the lower social class, as shown in [Table 3]. There was statistically significant difference between socioeconomic status and immunization status (χ2 = 10.460, P = 0.005).
With regard to father’s educational status, 149 (66.8%) were educated with a minimum of secondary school education, while only 91 (40.8%) of mothers had a minimum of secondary school education. The parental level of education is shown in [Table 4].
Eighty-two (36.8%) of the children of educated fathers were fully immunized compared to 21 (9.4%) of fathers with limited education. This was significant (χ2 = 14.134, P = 0.000). A similar trend was observed in children of educated mothers, with 59 (26.5%) fully immunized compared to 44 (19.7%) of children of mothers with limited education (χ2 = 21.507, P = 0.000).
All the fathers were alive and gainfully employed except three (1.3%) who were late, while 184 (82.5%) of the mothers were full-time housewives but not gainfully employed.
The reasons proffered for not completing immunization were mostly ignorance of dosing schedule or lack of approval by the father, as shown in [Table 5]. Other reasons included change in settlement, community disapproval of immunization, a long queue at the immunization facility, the father traveling, the absence of a health center in the area of residence, maternal ill health, and industrial action by medical personnel.
The immunization status of children seen at our facility was low despite health education through the media and an increase in the awareness of the benefits of immunization. The number of children fully immunized is lower than what was observed in Jos,  Ibadan,  Igbo-Ora,  Nairobi,  and in two districts in Kenya.  However, it was higher than what was observed by Itimi  et al. in Bayelsa and by Kumar  et al. in India. One reason for the low number of fully immunized children may be distrust formed as a result of rumors about the side-effects of vaccines in the northern part of the country, especially regarding the effect on fertility later in life.
More males were enrolled in our study, which is similar to what was observed in Jos  and Libreville,  in contrast to what was observed in Igbo-Ora,  Kenya,  and India. 
A progressive decline in the number of children vaccinated according to the immunization schedule was observed, as 70.7% of children had BCG, but only 48.9% and 46.6% had measles and yellow fever vaccines, respectively. In fact, less than half of the children were immunized after the age of 6 months. A similar trend of decline in children immunized according to the schedule was observed in Jos,  Kenya,  India,  and Sudan.  Infant mortality, which is high in Nigeria, as well as lack of knowledge of immunization schedules may explain the observed decline.
There was an observed disparity in the number of children immunized with vaccines administered simultaneously. This may be a result of the unavailability of some vaccines at the time of administration and due to immunization recall, as some parents could not remember if they were given at the same time. This was also observed by Adeyinka  et al. in Igbo-Ora.
Immunization status in our study was not associated with gender, contrary to what was observed by Angyo  et al. in Jos and by Kumar  et al. in India.
Most of our children were of low socioeconomic status, similar to what has been observed in other studies. , Low socioeconomic status was associated with poor immunization status, similar to what was observed by Angyo  et al. The reason may be that poor people are more likely to be uneducated and less likely to access health care centers to benefit from the services offered.
Both paternal and maternal levels of education were significantly associated with the immunization status of our study population. Only 41.3% of mothers had secondary school education and above, which is lower than the 81.6% observed in Libreville. 
The association of low maternal level of education with poor immunization status has also been observed in Kaduna,  Jos,  Kenya,  India  and Sudan.  This may be due to the fact that such mothers are not only ignorant of benefits of immunization, but may not recall the next date of the vaccination. Furthermore, they may not utilize available health services and hence may not take their children for vaccination. Even among the children of educated parents, immunization status was low, and this suggests the influence of other factors, such as culture and beliefs.
The reasons obtained for not completing immunizations were similar to what was obtained in other studies. ,,,,,, There is a need for health education of mothers on the necessity of taking their children for immunization even when the children are ill, because not all illnesses are contraindications to giving vaccinations. Mothers also need to be educated that their children can be given immunizations at any given health center whenever they travel or relocate, so that the children should not miss their next dose. There is a need to continue educating and reeducating fathers on the benefits of immunization, as they contribute significantly to the lack of or incomplete immunization. Religious leaders and community leaders are vital in the dissemination of information on the benefits of immunization.
This study was prone to recall bias: Although the parents were asked to recall the vaccines that were administered to their children, they do not carry immunization cards when going to the hospital or clinic. Some of the respondents did not give specific reasons for not taking their children for some of the vaccinations. These were some of the limitations of our study.
This study showed that a large proportion of under-five children attending our pediatric outpatient clinic were not fully immunized. The majority belonged to the lower socioeconomic class and their mothers were not gainfully employed.
Immunization services are widely available in Gusau and also accessible, but utilization is poor. The reasons given for not completing immunization can be overcome by educating both the parents about health, as fathers play a significant role in preventing the mothers from attending immunization clinics. Our religious and traditional leaders should also be included in sensitization programs to educate the community on misconceptions about immunization.
There is also the need to strengthen the communication, education, and information skills of our health workers to be able to identify not-fully-immunized children early and educate the mothers in order to reduce the number of missed opportunities in immunization programs.
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]