1.1 Background to the Study
Immunization is basically the process of fortifying a person’s immune system and making him or her resistant to an infectious disease through the use of vaccine, has gone a long way, and its importance cannot be downplayed. As recalled by Blackman (2008), a global vaccination programme was instrumental to the drastic reduction in the incidence of smallpox in the early 80’s. According to Plotkin, Orenstein, & Offit (2008), “Vaccines – With the exception of safe water, no other modality, not even antibiotics, has had such an effect on mortality reduction.” Vaccination is one of the cheapest and safest methods of primary prevention. In agreement to this, WHO (2015) asserted that immunization prevents about two to three million deaths of children yearly through vaccines and an additional 1.5 million deaths could be avoided if global vaccination coverage improves. It ensures safety of children, (especially those of them who are below five years of age) against the childhood deadly diseases, some of which include tetanus, poliomyelitis, diphtheria, hepatitis B, tuberculosis, yellow fever, measles and pneumonia.
Many public health agencies, including the Centre for Disease Control and Prevention (2013) had ranked immunization as one of the topmost discoveries in the field of Medicine owing to its proven effectiveness. It is also seen as an important landmark in Public Health since it checkmates the transmission of disease process thereby affording children and adults the opportunity to remain free of deadly diseases and enjoy good quality of life. As a result, the World Health Organisation and American Academy of Paediatrics recommended a series of immunizations starting immediately after birth. The initial series for children is completed by the time they reach the age of two, but booster vaccines are required for certain diseases, such as diphtheria and tetanus, in order to maintain adequate protection (Blackman, 2008).
The Expanded Programme on Immunization (EPI) was launched by WHO in 1974 (Itimi, Dienye & Ordinioha, 2015), with a recommendation that every country should not only adopt it but also develop strategies to ensuring its absolute implementation, so that no child is left out. In Nigeria, EPI was launched in 1979 and re-launched in 1984 (Antai, 2009). The main EPI service delivery strategies are; the static services/routine immunization services at health facilities (public and private), outreach services to communities without access to health facilities, mass campaigns in high-risk populations, reaching every district approach targeting hard-to-reach districts, generalized periodic national immunization days (NIDs), supplemented immunization activities (SIAs) organized for missed opportunities and drop-outs, and home visits, (WHO, 2005). According to the current schedule, a child is considered fully vaccinated if he has received a BCG vaccination, 3 doses of pentavalent vaccines, (diphtheria, tetanus, pertussis, hepatitis B and Haemophilus influenzae type b (Hib)), at least 3 doses of oral polio vaccine, 1 dose of Inactivated Polio vaccine (IPV), 1 dose of measles vaccine and 1 dose of yellow fever vaccines. Since the launch of EPI, developing countries like Nigeria, have struggled to meet the various immunization coverage targets and deadlines set by WHO, there was an encouraging coverage, which later became unsustainable especially in the rural places (Blackman, 2008).
The Millennium Development Goal (MDG) 4, whose target was to reduce by two thirds, between 1990 and 2015, the under-five mortality rate (U5MR), was 191 deaths per 1000 live births in 1990 but this was reduced to 89 deaths per 1000 live births in 2014, though this is still short of the 2015 target of 64 deaths per 1000 live birth by 28%, MDG – End Point Report (Ogenyi & Toure,2015). Infant mortality rate was estimated at 91 deaths per 1000 live births in 1990, stood at 58 death per 1000 live birth in 2014, this is still short of the 2015 target of 30 deaths per 1000 live births (Ogenyi & Toure, 2015). A decrease in the number of under-5 deaths and infants deaths caused by vaccine preventable diseases in every WHO region, would result in a corresponding decline in the global under-five mortality rate, this would in turn contribute towards achievement of Sustainable Development Goal (SDG) 3, with target 3.2 being to end preventable deaths of new-borns and children under 5 years of age, with all countries aiming to reduce neonatal mortality to at least as low as 12 per 1,000 live births and under-5 mortality to at least as low as 25 per 1,000 live births by 2030 (UN, 2015)
Many studies have reported various reasons for the difficulty in immunization coverage in Nigeria. Odusanya, Alufohai, Meurice, & Ahonkhai, (2008) Identified health system factors such as nature of health facility and maternal knowledge as reasons for low coverage among a rural population in Edo State. Inadequate levels of immunization against childhood diseases also remain a significant public health problem in resource-poor areas of Nigeria (Abdulraheem, Odajole, Jimoh, & Oladipo, (2011)).