CHAPTER ONE

INTRODUCTION

Background of the Study

The Bacille Calmette Guerin (BCG) vaccine remains critical for the development of new Tuberculosis  vaccines, many of which will be given as a booster vaccine after BCG vaccination, and any factors that affect how BCG works may also impact on these as well as on new genetically modified BCG vaccines or other live mycobacterial vaccines (Combs, 2014).

BCG vaccination immediately or shortly after birth provides consistent protection against the disseminated forms of TB in young children), and is very cost effective. Neonatal BCG also protects against pulmonary TB in children which contrasts with the variable protection seen against pulmonary TB in adolescents and young adults (Walter, 2016).

BCG vaccination is more protective against pulmonary disease in children and adults at higher latitudes and in those screened for prior sensitization by mycobacteria. Environmental mycobacterial are often assumed to be the culprits, mycobacteria species that survive in different environmental niches, and colonize humans over time (Jonnes, 2013). The impact of prior sensitization, as detected by tuberculin skin testing, on the protective efficacy of BCG against pulmonary TB has been shown in a number of settings but not whether this induces masking of the BCG vaccine effect (inducing protection that BCG cannot improve upon) or blocking (inducing pre-existing immune responses that prevent BCG vaccine-induced, protective responses).

One reason for limited progress has been the lack of antigens specific for environmental mycobacteria with which to dissect T-cell responses to the different mycobacteria other than tuberculosis or Non-Tuberculosis Mycobacteria (NTM; e.g., Mycobacterium avium). Skin test positivity to Mycobacterium tuberculosis purified protein derivative (PPD or tuberculin) increases with age, although indurations >10mm are less frequent in those who are BCG vaccinated. It is widely assumed that the effects of environmental mycobacteria or NTM would precede BCG vaccination, perhaps blocking BCG multiplication; however, this is unlikely for infants vaccinated soon after birth, and too little work has focused on their effects post-BCG. In the mouse model, oral dosing with NTMs following BCG vaccination decreased protection.

The BCG vaccine has been used since 1921 to prevent tuberculosis (TB) and is considered to be the world’s most widely used vaccine. Yet, it is well established that the protective efficacy of BCG varies depending in which geographical location it is administered and we understand very little about why it protects when it does, or why it fails to protect when it does not. This review will survey what we have learnt about BCG over the last 20 years. Although a lot of progress has been made, the past two decades have shown that there is no simple correlate of BCG-induced protection against TB even though T-cells and IFNγ are clearly required.

Neonatal BCG provides good protection against disseminated and pulmonary TB disease in young children but variable efficacy against pulmonary TB in adults when given later in life. However, when it does protect, this protection can be long-lived, lasting for up to 15 years in the United Kingdom, 30–40 years in Norway, and even as long as 50–60 years in Alaska. There is also evidence from outbreak settings to support the hypothesis that BCG vaccination can protect against infection, as well as disease; for example, an association has been observed between the presence of a BCG scar and not only less disease but also lower rates of interferon-gamma release assay (IGRA) positivity with relative risks for vaccinated compared with unvaccinated children of 0.61 for infection and 0.51 for disease.

Immunization against Vaccine Preventable Diseases (VPDs) through the Expanded Programme of Immunization (EPI) is one of the most economical public health interventions available that contributes extensively to achieving the Millennium Development Goal to reduce the mortality rate of children under five by two-thirds between 1990 and 2013 (UNICEF 2015, World Bank, 2015).

Childhood immunization is the initiation of immunity through application of vaccine. It is considered important for improving child survival. This is because more than 10 million children in developing countries die every year because they do not access effective interventions such as immunization that could fight common and preventable childhood illnesses (WHO, 2015).

Childhood Immunization is considered one of the greatest public health achievements of all time. According to the World Health Organization (WHO, 2015) immunization rates have increased at a rapid pace in recent years, and more children are immunize than in previous years. Immunizations are estimated to save two to three million lives annually worldwide. Diseases which at one point affected millions of children worldwide have now been eradicated, as evidenced by the elimination of smallpox in 1977 (Public Health Agency of Nigeria (PHAN, 2016).

Bacille Calmette Guerin (BCG) are administered at birth, while three doses of OPV and pentavalent vaccines (which protect against diphtheria, pertussis, tetanus, hepatitis B and Haemophilus influenzae type B disease) are given at interval, of four-week duration; at 6, 10 and 14 weeks and measles vaccine is given at the age of nine months (WHO, 2015). Less than half of children have received each of the recommended vaccinations, with the exclusion of polio 1 (67 per cent) and polio 2 (52 per cent) (NPC, 2015). And more than three times as many urban children as rural children are fully vaccinated (25 per cent and 7 per cent, respectively) (NPC, 2015).

The expanded Programme on Immunization (EPI) was established in 1974 against six vaccine preventable disease. These are diphtheria, polio, tuberculosis, measles, pertussis and tetanus. In 2003, DPT3 global coverage was 78 percent with about 27 million children not covered. South Asia and sub-Sahara African countries accounted for 9.9 million and 9.6 million, respectively of the children that were not covered. In most of these countries poor functioning health service delivery system impedes the efforts to meet immunization targets (WHO, 2015). Therefore, children living in remote location and border areas are difficult to be immunized with booster doses especially of polio and measles during the national or sub-national immunization days.

It is therefore important to highlights the factors associated with the acceptance of BCG coverasge in Nigeria in respect of the parents’ acceptability with a view to improve the quality of life of these children. Health care professionals have a responsibility to encourage childhood immunization and ensure the information provided to the public is evidence based and accurate, as this is an essential aspect of professional conduct for practice (Plastow, 2016).

One of the strategic objectives of the Global Vaccine Action Plan (GVAP) is to ensure that the benefits of immunization are equitably extended to all people. Achieving this objective will mean that every eligible individual is immunized with all appropriate vaccines – irrespective of age, gender, disability, educational level, socio-economic level, work condition, geographic location or ethnicity (WHO, 2017).

Routine Immunization (RI) systems are critical foundations for achieving and sustaining high levels of population immunity to vaccine-preventable diseases. The “Reaching Every District” (RED) strategy, with a focus on planning and monitoring, has been implemented to build capacity and expand the provision of immunization services. However, certain individuals or population groups continue to remain susceptible to vaccine-preventable diseases, either because they are missed by RI programmes or because of primary vaccination failures (UNICEF, 2015).

The above strategies have necessitated the researcher for the choice of strategies for improving coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayelsa State.

Statement of the Problem

In 2009, Nigeria was listed among countries with the highest incidence of poliovirus cases in the world. Immunization coverage against Polio and other VPDs were below targets at the national level (WHO, 2015). There are quite a lot of reasons for such low rates in Nigeria. Given the protective doses of immunization and the observed low immunization coverage in Nigeria, it is important to identify the factors influencing full child immunization among 12-23 months children in Nigeria so that child mortality and morbidity could reduce.

One major way to reduce child morbidity and mortality rates from common Vaccine Preventable Diseases (VPDs) is immunization. VPDs have caused more than 20 percent of death for children under five (Lee, 2015). From international comparative data, Nigeria’s immunization coverage rates are among the worst in the world (UNICEF, 2013). According to the 2008 National Immunization Schedule, the percentage of fully immunized children to be targeted was less than 1 percent in Jigawa, 15 percent in Yobe, 1.6 percent in Zamfara and 8.3 percent in Katsina. It was also revealed that only 23 percent of Nigeria children 12-23 months received all recommended vaccines as at 2008 that is one dose of BCG and measles and three doses each of DPT and polio (NPC, 2013). The same survey showed that 38 percent of children in Nigeria had not received any vaccinations.

Purpose of the Study

The purpose of this study is to determine the strategies for improving coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State. Specifically, the study seeks to find out the:

1.       Level of parental perceptions on the acceptance of coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State.

2.   Factors that affect the coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State.

3.       Strategies for improving the coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State.

Significance of the Study

The findings from this study would be used to develop recommendation for health care professionals to support, respect, and educate parents on coverage of BCG. The findings would benefits the government, community, students, policy makers among others.

Children in Primary Health Centre in Southern Ijaw Local Government Area of Bayesa State especially children under 5 year will live and grow healthier.

The health sectors in Southern Ijaw Local Government Area of Bayesa State would benefit because it will form the basis and strengthen the BCG coverage.

The households in Southern Ijaw Local Government Area of Bayesa State will benefit as their children will be immunized against 6 killer diseases. Also the community, local government area, state and the whole country will benefit from this study.

The study would provide knowledge on the needs for mothers to understand the importance of BCG coverage toward the killer diseases using the disease preventable vaccines.

The findings of the study would also help the government (state and LGAs) UNICEF, WHO and community to adopt strategies toward intensive  Immunization using Reaching Every Ward (REW).

Research Questions

The following research questions were formulated to guide this study.

1.       What is the level of parental perceptions on the acceptance of coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State?

2.   What are the factors that affect the coverage of BCG in Foropa Community in

      Southern Ijaw Local Government Area of Bayesa State?

3.   What are the strategies for improving the coverage of BCG in Foropa

      community in Southern Ijaw Local Government Area of Bayesa State?

Scope of the Study

The scope covers the strategies for improving coverage of BCG in Foropa Community in Southern Ijaw Local Government Area of Bayesa State. The factors affecting the coverage of BCG would be looked into with designed solutions.

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