Cluster sampling methodology to evaluate immunization coverage

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.

Rethinking Strategies to Address Inequity in Immunization Services towards Achieving Universal Immunization Coverage (UIC) in Karachi, Pakistan

Karachi, the largest city in Pakistan, having high population growth and a complex health care environment, has highest density of unimmunized (zero dose) and under-immunized children. The main reasons of low immunization coverage in Karachi were lack of governance and accountability in a duplicative and fragmented health management structure, weak and inequitable immunization services, and lack of demand and trust among people for immunization services. The Expanded Programme on Immunization (EPI), Ministry of Health (MOH) in Sindh Province spearheaded a structured and collaborative process to develop strategies for addressing inequity in immunization services towards achieving Universal Immunization Coverage (UIC) in Karachi. The process included a situation analysis with gathering quantitative and qualitative information on the root causes of zero-dose and inequity of the immunization services. The strategies and interventions were developed with multi-layer input and feedback of the stakeholders and partners, and focusing primarily to address gaps in three program areas: governance, leadership and accountability;immunization service delivery;and building demand and trust among the people. The interventions were further prioritized for high-risk areas;identified based on maximum number zero-dose children, presence of large slum areas, measles outbreak and on-going circulation of wild poliovirus. Finally, costing for the Roadmap activities was done through consultation with partners and aligning domestic and external (donor) resources. In this paper, we have highlighted the unique process the Sindh Government undertook in collaboration with the stakeholders and partners to develop strategies and interventions for addressing inequity in urban immunization services in Karachi towards achieving Universal Immunization Coverage (UIC). Similar processes can be adapted, as a potential model, for developing strategies to achieve universal health coverage in the cities of Pakistan and in other countries.

Immunization coverage,knowledge,satisfaction,and associated factors of non-National Immunization Program vaccines among migrant and left-behind families in China:evidence from Zhejiang and Henan provinces

Background Migrant and left-behind families are vulnerable in health services utilization,but little is known about their disparities in immunization of non-National Immunization Program(NIP)vaccines.This study aims to evaluate the immunization coverage,knowledge,satisfaction,and associated factors of non-NIP vaccines among local and migrant families in the urban areas and non-left-behind and left-behind families in the rural areas of China.Methods A cross-sectional survey was conducted in urban areas of Zhejiang and rural areas of Henan in China.A total of 1648 caregivers of children aged 1-6 years were interviewed face-to-face by a pre-designed online questionnaire,and their families were grouped into four types:local urban,migrant,non-left-behind,and left-behind.Non-NIP vaccines includedHemophilus influenza b(Hib)vaccine,varicella vaccine,rotavirus vaccine,enterovirus 71 vaccine(EV71)and 13-valent pneumonia vaccine(PCV13).Log-binomial regression models were used to calculate prevalence ratios(PRs)and 95%confidence intervals(CIs)for the difference on immunization coverage of children,and knowledge and satisfaction of caregivers among families.The network models were conducted to explore the interplay of immunization coverage,knowledge,and satisfaction.Logistic regression models with odds ratios(ORs)and 95%CIs were used to estimate the associated factors of non-NIP vaccination.Results The immunization coverage of all non-NIP vaccines and knowledge of all items of local urban families was the highest,followed by migrant,non-left-behind and left-behind families.Compared with local urban children,thePRs(95%CIs)for getting all vaccinated were 0.65(0.52-0.81),0.29(0.22-0.37)and 0.14(0.09-0.21)among migrant children,non-left-behind children and left-behind children,respectively.The coverage-knowledge-satisfaction network model showed the core node was the satisfaction of vaccination schedule.Non-NIP vaccination was associated with characteristics of both children and caregivers,including age of children(>2 years-OR:1.69,95%CI:1.07-2.68 for local urban children;2.67,1.39-5.13 for migrant children;3.09,1.23-7.76 for non-left-behind children);and below caregivers’characteristics:family role(parents:0.37,0.14-0.99 for non-left-behind children),age(≤35 years:7.27,1.39-37.94 for non-left-behind children),sex(female:0.49,0.30-0.81 for local urban children;0.31,0.15-0.62 for non-left-behind children),physical health(more than average:1.58,1.07-2.35 for local urban children)and non-NIP vaccines knowledge(good:0.45,0.30-0.68 for local urban children;7.54,2.64-21.50 for left-behind children).Conclusions There were immunization disparities in non-NIP vaccines among migrant and left-behind families compared with their local counterparts.Non-NIP vaccination promotion strategies,including education on caregivers,and optimization of the immunization information system,should be delivered particularly among left-behind and migrant families.

Comparison of Cost Incurred in Two Survey Methodologies for Measles Vaccine Coverage

Background: The World Health Organization (WHO) initiated the Expanded Program on Immunization (EPI) in 1974. It has been widely used in different studies. Along with this, other survey methodologies have been compared to study immunization coverage at different regions. To consider different survey methodologies, one of the most important factors is the cost incurred that survey methodology. A survey method is considered as more efficient or better than the other survey method if the cost incurred in a particular method is less than the other one. Methods: In this study, cost incurred in two stage (30 × 30) cluster sampling and systematic sampling methods have been compared using a cost function for measles vaccine coverage. Measles vaccine coverage data has been taken from the survey “Comparison of Two Survey Methodologies to Estimates Total Vaccination Coverage” sponsored by Indian Council of Medical Research (ICMR), New Delhi. Results: The results show that there are no significant differences between the point estimates of measles vaccine coverage under the considered survey methodologies. But the cost incurred in systematic sampling is more than that of two stage cluster sampling. Conclusion: It can be concluded that systematic sampling survey is costlier than that of two stage cluster sampling for this study population.