A cross-sectional study on determinants of immunization coverage in urban area Chidambaram, Tamil Nadu

INTRODUCTION

Immunization remains one of the most important and cost effective public health intervention to reduce morbidity and mortality due to infectious diseases in children. It prevents approximately 2-3 million fatalities in young children every year.¹ The WHO expanded programme on immunization (EPI) recommends that all children receive one dose of BCG, three doses of diphtheria-pertussis-tetanus vaccine (DPT), three doses of oral polio vaccine (OPV), three doses of hepatitis B vaccine and one dose of measles vaccine. The coverage for these major vaccine-preventable diseases has risen significantly since EPI began in 1974. Despite this progress, an estimated 1.5 million children worldwide die each year of diseases that can readily be prevented by these vaccines.²

In India, this universal immunization program (UIP) is the largest in the world with annual cohorts of around 26.7 million infants and 30 million pregnant women.³ The national family health survey-4 (NFHS-4) in 2015-2016 reports 62% of children aged 12-23 months were completely immunized in India (BCG, 3 doses of DPT, OPV, Hepatitis B and one dose of measles each). As per this national survey, 61.3% and 63.9% children of 12-23 months age have been fully immunized in rural areas and urban areas of India, respectively. Puducherry has the highest (91.3%) and Nagaland has the lowest (35.7%) percentage in terms of immunization coverage.⁴

Several socio-economic (lack of awareness, cultural beliefs, parents education, religion, number of children in the family, socioeconomic status, lack of trust in health services) as well as other factors (poor quality of services, inadequate staffing and irregular supply of vaccines) are important determinants of immunization coverage.⁵

Thus the objective of this study was to assess the immunization coverage and its determinants in children aged one to three and half years in urban field practice area of Rajah Muthiah medical college, Chidambaram.

METHODS

This community based cross-sectional study was conducted between September to October 2018 for a period of one month in urban area of Chidambaram. The study participants were all the children aged 12 to 42 months living in urban Chidambaram. Respondents whose parents refused to be a part of the study are excluded. Considering the prevalence of full immunization coverage in a study done by Duraimurugan M et al in urban area of Kanchipuram as 76% sample size was calculated to be 70 using the formula⁶,

where Z=reliability coefficient (1.96), P=Prevalence, Q=1 - P, d2=absolute precision of 10%.

House to house survey was conducted using convenient sampling technique. Details of immunization coverage was obtained from immunization card or mother’s recall if the card is not available. Pretested semi-structured proforma was used to collect socio-demographic details.

Operational definition

Infants who receive one dose of BCG, three doses of each of OPV, DPT and hepatitis B and one dose of measels vaccine before reaching one year of age is said to be fully immunized.

Infants who received any one or two doses but not all the vaccines within one year of age is said to be partially immunized.

Infants who have not received any vaccines before one year of age is said to be unimmunized.

Statistical analysis

Data collected were coded, classified and analyzed using SPSS (statistical package for social sciences) version 20. The statistical test used to determine the attributes include descriptive statistics and chi-square test. The level of significance was fixed at 5%.

RESULTS

Majority of the study population were males (55.9%) and belong to hindu community (80.3%). Majority (80.3%) were fully immunized and 19.7% were partially immunized. Most of the mothers had taken regular antenatal care and most of the children were born in healthcare facility (99.3% each). Most of the children (92.8%) had birth certificates. Unaware of the need of immunization (40%), unaware of need to return for subsequent doses (23.3%) and fear of side effects (16.7%) are the important reasons for failure of full immunization. Immunization coverage increased with the literacy status of parents (87.5% and 91.3% among higher secondary or graduate father and mother respectively) and was highest (91.9%) when fathers do skilled jobs which was statistically significant. The coverage is higher among first birth order (88.3%), when born in healthcare facility (80.8%) and mothers who received antenatal care (80.8%) and was significant. There was no significant association between immunization coverage and gender, religion, mother’s occupation and age, family income, type and size.

DISCUSSION

Immunization plays an important role in preventing illness and improving health of the children. Full immunization coverage in our study was 80.3% which is similar to the study conducted by Murhekar et al in Tamil Nadu, where it was 78.8% and 79.4% as per the study by Joy et al in Kochi, Kerala whereas it was only 50% in rural Uttar Pradesh in a study done by Ahmad et al.^7-9 In the present study the main reason for failure of full immunization was unaware of need of immunization (40%) and need to return for subsequent doses (23.3%). Similar results were given by Nath et al in urban slums of Lucknow.¹⁰

Girl-to-boy coverage ratio of less than 1 was found in most states of India and has not changed despite improved vaccination practices.¹¹ There was no association between gender and immunization coverage in this study which is contrast to findings given by Devasenapathy et al where girl to boy complete immunization coverage was 0.78.¹²

Immunization coverage increased with mother’s literacy which is concordant with the findings shown by Johri et al.¹³ Illiteracy of the mother was significantly associated with partial immunization similar to the results were given by Nath et al.¹⁰ There was no association between religion and immunization coverage in contrast to the study done by Devasenapathy et al where muslim households had lower complete immunisation.¹²

Similar to the findings of Kulkami et al hospital based child births and antenatal care are associated with good immunization practices.¹⁴ A study in Kenya found that a child who was delivered in a health facility was 2.26 times more likely to receive full immunization compared to one delivered at home or by a traditional birth attendant.¹⁵

CONCLUSION

Complete immunization in the study area was 80.3%. In order to achieve 100% immunisation coverage vulnerable and inaccessible households should be targeted by effective outreach interventions. Lack of awareness and sociocultural beliefs were important determinants of immunization coverage. These social barriers need to overcome by improving parents literacy and ongoing motivation by professionally designed behavioural change communication interventions.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

REFERENCES

1. 1. World Health Organization. Fact sheet: Immunization, 2019. Available at: https://www.who.int/news-room/facts-in-pictures/detail/immuniz-ation. Accessed on 29 January 2021.
2. 2. World Health Organization. The expanded programme on immunization. Available at: https://www.who.int/life-course/news/comment-aries/vaccine-preventable-diseases/en/. Accessed on 1 February, 2021.
3. 3. Gurnani V, Haldar P, Aggarwal MK, Das MK, Chauhan A, Murray J, et al. Improving vaccination coverage in India: Lessons from intensified mission indradhanush, a cross-sectoral systems strengthening strategy. BMJ. 2018;363:4782.
4. 4. State/UT-wise Percentage of Children (12-23 months age) fully immunized as of NFHS-4 | Open Government Data (OGD) Community. http://niti.gov.in/content/immunisation. Accessed on 25 January 2021.
5. 5. Duru C, Iwu A, Uwakwe K, Diwe K, Merenu I, Emerole C, et al. Assessment of immunization status, coverage and determinants among under 5-year-old children in Owerri, Imo State, Nigeria. Open Acc Lib J. 2016;3(6):1-17.
6. 6. Duraimurugan Murugesan, Ramasubramanian R. A study on immunization coverage of 12 - 23 months children in urban areas of Kanchipuram district, Tamil Nadu. Int J Community Med Public Health. 2017;4(11):4096-100.
7. 7. Murhekar MV, Kamaraj P, Kanagasabai K, Elavarasu G, Rajasekar TD, Boopathi K, et al. Coverage of childhood vaccination among children aged 12-23 months, Tamil Nadu, 2015, India. Ind J Med Res. 2017;145(3):377-86.
8. 8. Joy TM, George S, Paul N, Renjini BA, Rakesh PS, Sreedevi A. Assessment of vaccine coverage and associated factors among children in urban agglomerations of Kochi, Kerala, India. J Fam Med Prim Care. 2019;8(1):91-6.
9. 9. Ahmad J, Khan ME, Hazra A. Increasing complete immunization in rural Uttar Pradesh. J Fam Welf. 2010;56:65-72.
10. 10. Nath B, Singh JV, Awasthi S, Bhushan V, Kumar V, Singh SK. A study on determinants of immunization coverage among 12-23 months old children in urban slums of Lucknow district, India. Indian J Med Sci. 2007;61(11):598-606.
11. 11. Prusty RK, Kumar A. Socioeconomic dynamics of gender disparity in childhood immunization in India, 1992–2006. PLoS One. 2014;9(8):104598.
12. 12. Devasenapathy N, Ghosh Jerath S, Sharma S, Allen E, Shankar AH, Zodpey S. Determinants of childhood immunisation coverage in urban poor settlements of Delhi, India: a cross-sectional study. BMJ Open. 2016;6:013015.
13. 13. Johri M, Subramanian SV, Sylvestre MP, Dudeja S, Chandra D, Kone GK et al. Association between maternal health literacy and child vaccination in India: a crosssectional study. J Epidemiol Community Health. 2015;69(9):849-57.
14. 14. Kulkarni SV, Chavan MK. A study to assess the immunization coverage in an urban slum of Mumbai by lot quality technique. Int J Med Public Health. 2013;3(1):21-5.
15. 15. Maina LC, Karanja S, Kombich J. Immunization coverage and its determinants among children aged 12-23 months in a peri-urban area of Kenya. Pan Afr Med J. 2013;14:3.