IJPHCS International Journal of Public Health and Clinical Sciences Open Access: e-Journal e-ISSN : 2289-7577. Vol. 4:No. 5 September/October 2017 PREDICTORS OF ADHERENCE TOWARD CHILDHOOD IMMUNIZATION OF UNDER FIVE CHILDREN Zamzaireen Z.A.1,2, Muhamad Hanafiah Juni1*, Faisal I1 1Department of Community Health, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. 2Ministry of Health, Malaysia *Corresponding author: Associate Professor Dr. Muhamad Hanafiah Juni Email: [email protected] ABSTRACT Introduction: Vaccine preventable diseases are occuring despite high immunization coverage. Hence, the predictors of adherence toward childhood immunization are important to be identified. A cross-sectional study conducted to determine the predictors of adherence toward different vaccines of childhood immunization among mothers of under five children. Materials and Methods: Recruitment of 320 respondents into the study was via systematic random sampling technique. Validated self administered questionnaires and proforma were used as the study instruments. Descriptive and inferential statistics were analyzed using SPSS version 22. Multiple logistic regression conducted for the analysis of predictors. Result: Response rate of 98.1% was obtained from 314 respondents. Adherence (completeness) towards childhood immunization and adherence (timeliness) towards different vaccines were 98.09% and 56.5% - 97.1% respectively. The predictor of adherence (completeness) was household income category of RM2000 to RM2999 (p=0.047). The predictors of adherence towards vaccine timeliness were; employed mothers towards BCG vaccine (p=0.011), third and onwards born children towards Hepatitis B dose one vaccine, (p=0.049), 25 year old and above mothers towards Hepatitis B dose two vaccine (p=0.038) and household income of RM5000 and more towards MMR dose one vaccine, (p=0.044). Conclusion: High adherence (completeness) towards childhood immunization relatively differs with the lower adherence (timeliness) towards different vaccines and its doses. Household income was the predictor for adherence (completeness). Predictors of vaccine timeliness included; mother’s employment status for BCG vaccine, birth order for Hepatitis B dose one vaccine, maternal age for Hepatitis B dose two vaccine, and household income for MMR dose one vaccine. Keywords: Predictor, adherence, childhood immunization, under five children Zamzaireen Z.A., Muhamad Hanafiah Juni, Faisal Ibrahim 111 IJPHCS International Journal of Public Health and Clinical Sciences Open Access: e-Journal e-ISSN : 2289-7577. Vol. 4:No. 5 September/October 2017 1.0 Introduction Immunization coverage is one of the nation’s important health indicator. The denominators are estimation of live births from the Department of Statistics, Malaysia and also the National Tuberculosis Information System Manual, TBIS (Ministry of Health Malaysia, 2015). Global immunization coverage in mid 2015 was; BCG 88%, Hep B 84%, DTP1 91%, DTP3 86%, HIB 64%, Polio 86%, MCV1 85% and MCV2 61% (World Health Organization, 2017). Immunization coverage for Malaysia in the same year was; BCG 98.53%, third dose Hep B 99.27%, third dose DPT-Hib 99.04%, third dose Polio 99.04% and MMR 93.07% (Ministry of Health Malaysia, 2016). However, there is still occurence of vaccine preventable diseases despite high immunization coverage (Ministry of Health Malaysia, 2012, 2013, 2014). Adherence towards childhood immunization provides maintenance of herd immunity against vaccine preventable diseases and non-immunized susceptible individuals (Blumberg, Enanoria, Lloyd-smith, Lietman, & Porco, 2014). Adherence are measured by completeness and timeliness towards childhood immunization (Tauil, Sato, & Waldman, 2016; Yu Hu, Yaping Chen, Jing Guo, Xuewen Tang, & Lingzhi Shen, 2014). Completeness is obtaining the recommended vaccines from National Immunization Programme (Barreto & Rodrigues, 1992; Tauil et al., 2016). Timeliness is the accepted intervals between vaccine doses and also valid minimum ages to receive the vaccines (Luman et al., 2005; Tauil et al., 2016). Four days earlier (Centers for Disease Control and Prevention, 2011) and up to seven days (Daniel Ansong et al., 2014; Riise et al., 2015) after recommended age are considered as valid. Adherence (completeness) with vaccine timeliness toward childhood immunization is an important effort towards reducing vaccine preventable diseases (Dummer, Cui, Strang, & Parker, 2012). Non-timeliness (non-adherence) towards immunization subsequently lead to unprotected children (Fadnes et al., 2011), being exposed to vaccine preventable diseases (Blumberg et al., 2014). Nationally, in 2016, there was an eight-year-old death in Langkawi, Kedah, due to Diphtheria and history of incomplete immunization (Director General of Health, Malaysia, statement release in January 5th, 2016). There were other 28 cases of Diphtheria and five deaths leading to a stern advice on the importance of immunization completion to prevent vaccine preventable diseases (Director General of Health, Malaysia in August 26th, 2016). Seroconversion is age-dependent hence infants should acquire protection early (Ministry of Health Malaysia, 2004). Non-adherence towards immunization may give a rise on the susceptibility period among children (Yu Hu et al., 2014). Associating factors influencing adherence (both completeness and timeliness) are socio- demographic characteristics, child factors, healthcare services and logistics. Socio- demographic characteristics consist of; maternal age (Kusuma, Kumari, Pandav, & Gupta, 2010), religion (Jani et al., 2008), education level (Calhoun et al., 2014), employment status (Vasudevan et al., 2014), marital status (Babirye et al., 2012), number of children (Mbengue et al., 2017) and household income (Kawakatsu & Honda, 2012). Child factors include; birth order (Rejali, Mohammadbeigi, Mokhtari, Zahraei, & Eshrati, 2015) and caregiver that is not fully the child’s mother (Fiks et al., 2006). Healthcare services are the usage of government and private healthcare services (Dummer et al., 2012). Logistics factor consist of; distance (Jani et al., 2008) and accessibility to health facility (Odutola et al., 2015). Based on these factors, this current study aimed to determine the predictors of adherence toward childhood immunization among mothers of under five children attending Klinik Kesihatan Seremban. Zamzaireen Z.A., Muhamad Hanafiah Juni, Faisal Ibrahim 112 IJPHCS International Journal of Public Health and Clinical Sciences Open Access: e-Journal e-ISSN : 2289-7577. Vol. 4:No. 5 September/October 2017 2.0 Materials and Methods Study location was in Klinik Kesihatan Seremban, Seremban district, Negeri Sembilan. Cross-sectional study was the design conducted. Study population was mothers with under- five children attending the child health clinic. List of attendances of mothers with under five children attending immunization in the child health clinic was the sampling frame. Final sample size was 320. Systematic random sampling with fixed interval of five was implemented for selection of respondents. All mothers with under-five children attending child health clinic for childhood immunization purpose were included. Non-citizen mothers and also younger child (of mothers with multiple under-five children) excluded. Validated self-administered questionnaires and proforma used for data collection. Data analyzed using the Statistical Analysis of Social Sciences System (SPSS) version 22.0. Frequencies, percentages, mean and median illustrated in figures or tables for descriptive analysis. All independent variables with p value less than 0.25 obtained from bivariate analysis included for multivariate analysis to determine the predictors. Confident interval was 95% and significance level for the said analyses was 0.05. Approval had been obtained from Medical Research and Ethics Committee, Universiti Putra Malaysia Ethics Committee for Human Research, JKEUPM (UPM/FPSK/JKK-GS46530- 2016/2017), Negeri Sembilan State Health Department and Seremban Health District Office. Written informed consents from respondents were attained prior to collection of data. 3.0 Result 3.1 Response Rate Out of 320 questionnaires distributed to eligible respondents, 314 consented and completed the questionnaire, giving a response rate of 98.1%. The remaining did not provide consents. 3.2 Descriptive Analysis 3.2.1 Socio-demographic Characteristics of Respondents In Table 1, the majority of respondents were 25 years old and more (85.0%), Malay ethnicity (38.2%), Muslim (39.5%), attained secondary school as the highest level of education (43.0%), employed (60.2%), married (99.7%) and having total household income of RM5000 and more (37.3%). Other ethnicities of respondents include Orang Asli, Dusun, Rungus, Kadazan, Iban and Punjabi. Other religions’ include having no religion, Sikh and Bahai. Zamzaireen Z.A., Muhamad Hanafiah Juni, Faisal Ibrahim 113 IJPHCS International Journal of Public Health and Clinical Sciences Open Access: e-Journal e-ISSN : 2289-7577. Vol. 4:No. 5 September/October 2017 Table 1: Socio-demographic characteristics of respondents (N=314) Characteristics Mean ± SD Median ± IQR n (%) Maternal age (years) 30.27 ± 4.91 < 25 years old 47 (15.0%) ≥ 25 years old 267 (85.0%) Ethnicity Malay 120 (38.2%) Chinese 90 (28.6%) Indian 95 (30.3%) Others 9 (2.9%) Religion Islam 124 (39.5%) Christian 29 (9.2%) Hindu 80 (25.5%) Buddha 76 (24.2%) Others 5 (1.6%) Education level