Evidence Based Public Health

Immunization is an effective strategy to combat key disease that affects children and improve their survival rate. Despite the immunization drive, many children from low- and middle income countries (LMICs) do not have access to full vaccine coverage according to national routine immunization schedule. Based on this problem, the Cochrane review article focussed on interventions for improving the childhood immunization coverage in LMICS. It purposes was to evaluate the methods taken by countries to improve childhood immunization coverage. The Cochrane researchers searched different clinical trials and selected studies were randomized controlled trials (RCTs), non-randomized controlled trials (nRCTs), controlled-before-after studies (CBA) and interrupted time series (ITS) to evaluate the immunization coverage strategy. It identified why several countries still die from disease even though vaccines could be used to avoid death. A number of reasons exist for this and the rationale for this review was to find ways by which maximum number of children is protected from disease by vaccination. The rationale for intervention strategy was that giving information to community members about vaccination, identifying children who has not been vaccinated through home visit and handing out vaccination reminder cards would be an useful approach to increase vaccine coverage among children. To bridge the gap and to realize a full potential of the immunization procedure a systematic intervention plan is the need of the hour. In this summary an evaluation of the effect of myriads of strategies to raise the count of children in LMICs for the prevention of disease was done by analyzing 14 relevant studies to envision a world where children will enjoy the right to live life free from diseases which are vaccine preventable.

The aim of the review is to analyze the efficiency of strategies to augment and to increase childhood immunization coverage in these LMICs. Four individually randomized trials which were controlled and ten RCT cluster which met the inclusion criteria were used for the purpose of this review which were conducted in Nicaragua, Ghana, Zimbabwe, Georgia, Mexico, Honduras, India, Pakistan, Mali and Nepal. The PICOT table based on the selection criteria for considering studies for the purpose of this review is enlisted below

The review citing WHO 2012 report showed that the key criteria for minimization of bias were done by strictly adhering to Cochrane guidelines. Two researchers applied the EPOC’s (Cochrane Effective Practice and Organization of care) risk of bias criteria for the selected studies to determine the risk of bias in the study. All disagreements were resolved by consensus and risk of bias was classified into ‘low risk’, ‘unclear risk’ or ‘high risk’. The risk of bias was presented for each included study. The reviewers decided that if all criteria prescribed by EPOC was met, then it will be categorized as ‘low risk of bias’ and if one or more criteria remained unclear, then no score will be given. The criteria required by EPOC included clear outcome data, hiding outcome assessors, allocation concealment, protection against contamination, independence of intervention and affect on data collection (Oyo‐Ita et al., 2012).

The interventions are broadly classified in to four approaches as per the figure.

Figure 1 showing the different intervention to maximize immunization coverage

The Cochrane review first summarized the efforts taken by WHO to maximize immunization drive and then gave details on effect of vaccination coverage strategy on different people. World Health Organization (WHO) was responsible for launching the Expanded Programme on Immunization (EPI) in 1974 after the successful eradication of small pox as cited by Wiysonge in 2013. The number of children receiving doses three times of diptheria-tetanus-pertussis (DTP3) is used as a scale to gauge the performance of EPI programmes. This programme promises to put a stop to 2.5 million children deaths from tuberculous meningitis and poliomyelitis. In spite of this, every year over a million children especially in the LMICs fail to receive the full vaccine course prescribed in the immunization national routine schedule. The WHO strived for a commendable achievement in curbing the death toll of children all over the world in preventing diseases which falls under the prevention by EPI. However, as cited by WHO 2015, globally children 18.7 million under one year of age were not vaccinated in 2014 with DTP3 where 57% -70 % of the number fall in ten such LMICs in African and South East Asian countries respectively. Progress of immunization coverage of DTP3 in these countries is very slow even though it reported 86% coverage globally in 2014 as cited by UNICEF in 2015. A well-structured decision about what interventions might work by analyzing scientific evidence will help to attain the desired outcomes in these countries (Oyo‐Ita et al., 2012).

The WHO 2012 report highlighted that studies carried out in India and Pakistan under health education carried out an information campaign in India involving poster distribution and audiotape messages and targeted pictorial messages were provided in Pakistan in the form of leaflets as cited by Andersson in 2009. Three more studies were done in Nepal and Pakistan in providing health education at a facility. Under Monetary incentive intervention, cash transfer in Mexico was a provision if the conditions such as receiving regular immunization, monitoring growth and attendance of mothers in hygiene, health and nutrition education programs were met. In Nicaragua, a monthly cash transfer for “food security” based on the condition on attending workshops in health educations. In Zimbabwe, a cash transfer of 18 US Dollars per every household was proposed and if anyone had child below 18 years with no birth certificate, then they has to apply for it within three months. Also, by the “reminder type” card of immunization provision two such studies were evaluated. In Georgia, provider oriented intervention was observed were supportive supervision in a continuous manner as well as various tools for immunization were developed. In home visits program in Ghana, under graduate students conducted the visits to aim for the non-immunized children and referring them to health centers as cited by Brugha in 1996. Integrating various services like measures to prevent malaria and immunization were clubbed to assess the effects was shown by Dicko in 2011.  In Honduras, as cited by Morris in 2004, a multifaceted approach set up a quality assurance teams in health centers which worked out a plan to include structural repairs, equipment purchase, drugs and materials at the centers. The aim of the QA training was to ensure that the quality of services is met by optimum utilization of services (Oyo‐Ita et al., 2012).

The interventions shown in the figure were basically implemented as single interventions or as multi-faceted interventions. As per the review, with a moderate certainty it can be said that vaccination discussion with parents and giving information to members of the community at meeting in villages or home improve the coverage of immunization. Monetary incentives (which are in the form of various conditions of cash transfers as well as vouchers) may have very minimal effect. Also, with low certainty, provision of reminder type immunization card to parents combined with information regarding importance of vaccination may improve the coverage. Home visits, regular outreach programs of immunization by integrating with other health care services such as malaria treatment can also aid in immunization coverage although with low certainty (Oyo‐Ita et al., 2012).

The type of interventions that was implemented in the study included recipient-oriented interventions, provider oriented interventions, health system interventions, multi-faceted interventions and other type of interventions to improve vaccine coverage in selected population. Recepient oriented intervention intended to improve communication about childhood immunization through education, teaching skills, facilitating decision, meeting vaccination requirement for school entry and using recipient incentives. The aim of provider oriented intervention was to reduce missed chance of childhood vaccination by auditing and giving feedback and giving health education. Health systems interventions targeted at improving quality of services by improving cold storage system, vaccine stock management and arranging for transport of vaccination materials. It aimed to expand services and arrange school immunization programme and door to door vaccine promotion. Other forms of interventions also helped to improve immunization coverage in selected countries (Oyo‐Ita et al., 2012).

The current analysis of the evidence provides that the likelihood of the consequences of the interventions will vary widely; hence it offers scope for future research to evaluate:

• The participant reminding and recall suitable interventions which are effective in all countries.
• The adoption of community based health strategies such as mass campaigns instead of facility based which has shown more promise (Hall et al., 2014).
• Multifaceted intervention and provider oriented ones for improving childhood immunization coverage.
• Regulation to make entry in school compulsory to increase coverage.
• Incentive provision program for providers of vaccination.
• An action plan for immunization coverage and reduction of disease. This may include measuring sustainability such as integrating into routine service related to immunization, interventions with long term impact and incidence of the targeted diseases. Secondly, the effectiveness of cost of the interventions for different strategies (Machingaidze et al., 2013).

Certain gaps in the study were also identified by Cochrane review. From the interventions which were tested in the review don’t give a clear understanding whether they were tested in recognizable hindrance. The interventions studies varied considerably in their delivery which naturally raises questions regarding the credibility of its impact in different setting. For example, questions such as how likely it is that a short health education campaign be effective in improving the immunization schedule. How much effective an evidence based approach in a low literacy setting. How much likely that provision of monetary perks will work in an area with poor resource setting. As per Wiysonge et al., (2012), home visits may prove to be effective to deliver vaccine, but the use of college students or workers in community health may not be feasible in a resource deficit area.  The wider applicability of this evidenced based research is difficult to explore due to discrepancy in identifying the potential barriers. The varied diversity as well as contextual differenced make it difficult to provide long term implications. Secondly, referring children to immunization requires that the vaccination center be nearby and hence this type of intervention may not work where the centers are not in walking distance. There is lack of data on the interventions sustainability presented in this review, because none of the studies included in this review, reported long-term following up of data (Wiysonge et al., 2015).

An estimated 2 to 3 million deaths every year are averted from diphtheria, tetanus and whooping cough (Pertussis) and measles. However, unfortunate 1.5 million deaths could be undone if immunization cover increases. To improve the childhood immunization coverage in LMIC, providing parents and the community as a whole with information, education in health in combination with reminder card of immunization, various outreach programmes with or without monetary benefits, visits at home, integrating immunization with other may prove to enhance the overall childhood immunization coverage in Low and middle income countries. But it should be kept in mind that the interventions were reported with a low certainty and most of the setting specific criteria needs to be considered as these interventions will be substantially differ in different areas. A thoroughly conducted RCT to fully assess the effects of interventions has to be undertaken.

Oyo‐Ita, A., Nwachukwu, C. E., Oringanje, C., & Meremikwu, M. M. (2012). Cochrane Review: Interventions for improving coverage of child immunization in low‐and middle‐income countries. Evidence‐Based Child Health: A Cochrane Review Journal, 7(3), 959-1012.

Machingaidze, S., Rehfuess, E., von Kries, R., Hussey, G. D., & Wiysonge, C. S. (2013). Understanding interventions for improving routine immunization coverage in children in low-and middle-income countries: a systematic review protocol. Systematic reviews, 2(1), 1.

Wiysonge, C. S., Young, T., Kredo, T., McCaul, M., & Volmink, J. (2015). Interventions for improving childhood vaccination coverage in low-and middle-income countries. SAMJ: South African Medical Journal, 105(11), 892-893.

Wiysonge, C. S., Uthman, O. A., Ndumbe, P. M., & Hussey, G. D. (2012). Individual and contextual factors associated with low childhood immunisation coverage in sub-Saharan Africa: a multilevel analysis. PLoS One, 7(5), e37905.

Hall, C. S., Fottrell, E., Wilkinson, S., & Byass, P. (2014). Assessing the impact of mHealth interventions in low-and middle-income countries–what has been shown to work?. Global health action, 7.