Study design and settings
A community based cross-sectional study design was conducted among mothers/caregivers of children aged 12 to 23 months at Jabitehnan district, northwest Ethiopia. The study was done from February to March 2020. Jabitehnan is located 180 Km in the southwest of Bahir Dar (Capital city of Amhara National Regional State) and 387 Km in the northwest of Addis Ababa (Capital city of Ethiopia). The estimated population of the district in 2019/2020 based upon 2007 Central Statistical Agency (CSA) of Ethiopia was 228,246, of whom 112,982 were males and 16,045 (7.03%) were urban inhabitants. It has around 30,905 under five children and around 15,526 under two children and 6163 children aged 12 to 23 months (24). The district has thirty-nine rural and three urban kebeles. On top of that, there are eleven health centers and 41 health posts in the district. All of these health facilities provide both outreach and static childhood vaccination services.
Population and sampling procedures
The source and study population were all children aged 12 to 23 months who had started vaccination and vaccination card or registered in childhood vaccination register in Jabitehnan district and selected kebeles of the district, respectively. All mothers /care givers of children aged 12 to 23 months who had started vaccination and who had a vaccination card or a vaccination register in the selected kebele were included in this study, however, those who were severely ill during data collection and children who had vaccination cards but no registration date of vaccination or date of birth either in the card or in the infant immunization register were excluded from the study.
The sample size was determined using the single population proportion formula by assuming a 6.2% proportion of children received timely vaccination study in northeast Ethiopia (22), 3% margin of error, 95% confidence level, 10 % non-response rate and 2 design effect. The final sample size was 548.
A multi-stage simple random sampling technique was used to select study participants. First the kebeles of the district were stratified to 39 rural and 03 urban. From the total of 42 kebeles in the district ten (one urban and nine rural) were selected randomly using the list of all eligible children aged 12 to 23 months from the family folder and infant immunization registers of the selected health posts. Health extension workers update the information recorded in the family folder at least once per month in every health posts. The list of all eligible children obtained from the health posts family folder were cross-checked with the infant immunization registers in the health posts and health centers to confirm the missing of eligible children from the sampling frame. The complete list of all eligible children in the selected kebele containing information about the name of a child, his/her parent’s full name, household’s unique identification number and sub-kebele/gotte/ was prepared by using family folders and infant immunization registers of the health posts and health centers. Proportional allocation of the sample was made to determine the required sample size from each selected kebele. Finally, simple random sampling technique was employed to select the required number of children from each selected kebele using the listed children as a sampling frame. The mothers/care givers of the index children were identified using the unique ID of the household in the selected kebeles.
Variables and measurement
Vaccination timeliness was the dependent variable, while socio-demographic related factors, such as age, sex of child, income, occupation, marital status, educational status of parents, residence, religion of parents, household size and birth order; access related factors: distance from vaccination site, mode of transportation, season of birth, availability of phone, availability of electronic media and place of vaccination; obstetric related factors: ANC visit, PNC visit, maternal conference participation, TT vaccination, pregnancy status, institutional delivery, birth attendance and parity; maternal awareness related factors: knowledge about vaccination and attitude towards vaccination were the independent variables.
Timely vaccination: a child is considered to be timely vaccinated, If the child received BCG within the first fifty-six days, OPV1, penta1, PCV1 and Rota1 from 39 to 70 days, OPV 2, penta2, PCV2 and Rota 2 from 67 to 98 days, OPV3, penta3 and PCV3 from 95 to 126 days and measles vaccine 270 to 301 days of age of the child (6, 22). On the other hand, the child was considered as early vaccinated when the child received at least one dose of the vaccine below the minimum recommended age for each antigens, and considered as delayed vaccination when the child received at least one dose of the vaccine above the maximum recommended age (6, 22).
Good knowledge: Twelve knowledge assessment item questions each containing (0=no and 1=yes) alternatives were used and those who scored greater than 50 % of the total knowledge measuring score was considered as having good knowledge (25).
Favorable attitude: Eight Likert scale attitude assessment item questions each containing (1=strongly disagree, 2=disagree, 3=neutral, 4=agree and 5= strongly agree) alternatives were used and those who scored 75% or more the attitude measuring score were considered as having favorable attitude (22, 26).
Data collection tools and procedures
The data were collected using interviewer administered semi-structured questionnaire. Five data collectors (nurses) and two supervisors (Health officers) were used for data collection. The questionnaire had socio-demographic, awareness, obstetric characteristics of mothers, and access related factors parts. The questionnaire was prepared first in English and translated to Amharic and then back to English to maintain consistency. One day training was given for both data collectors and supervisors on the basic techniques of the data collection procedures. Pre-test was conducted at Dembecha district among 28 (5%) mothers/caregivers of children aged 12 to 23 months who had started vaccination and had a vaccination card or a list in the infant immunization register, and necessary modification was made based on the pre-test findings. Completeness and consistency of the data were checked on the spot and daily basis by the supervisors and the principal investigator.
Data processing and analysis
The data were entered, cleaned and coded using Epi data software version 4.6 and exported to Statistical Packages for Social Sciences (SPSS) (version 22.0 Software for analysis. Descriptive statistics, such as mean, median, frequency and percentage were presented using texts, graphs and tables. Binary logistic regression model was used to identify factors associated with childhood vaccination timeliness. Those independent variables with p-value less than 0.2 during bi-variable analysis were taken into multivariable logistic regression analysis (22). Adjusted odd ratio (AOR) with 95% confidence level (95%CI) and p-value less than 0.05 during multivariable logistic regression were used to declare statistically significant association with childhood vaccination timeliness and the strength of association.