Cluster sampling methodology to evaluate immunization coverage

Abstract

BACKGROUND Immunization is a key component of primary health care and an indisputable human right. Vaccines are critical to the prevention and control of infectious disease outbreaks. The coronavirus disease 2019 (COVID-19) pandemic and associated disruptions over the past two years have strained the health systems, with many children missing out on essential childhood vaccines. AIM To evaluate the immunization coverage among 12-23-month-old children in the rural areas of Community Health Centre (CHC) Dighal and to determine the factors influencing the existing immunization coverage. METHODS A coverage evaluation survey was conducted according to the 30-cluster sampling technique, which is the standard methodology for such surveys devised by World Health Organization. A total of 300 children aged 12-23 months were included, whose immunization details were noted from their immunization cards. RESULTS Full immunization rate was noted in 86.7% of the children, with partial and non-immunized children accounting for 9% and 4.3% respectively. The full immunization dropout rate was 4.2%. The common reasons for partial or non-immunization were family problem including illness of mother, vaccine not being available and child being ill. Place of birth (P = 0.014) and availability of immunization card (P < 0.001) were significant predictors of the immunization status. Since the study was conducted in 2020/2021, health services were disrupted due to the COVID-19 lockdown. CONCLUSION Due to the coverage being higher than the national average, it was concluded that the immunization coverage was optimal and not affected by the COVID-19 pandemic.