Knowledge on Vaccination Schedule and Full Immunization, and Its Effect on Vaccine Take-up in Jada Local Government Area in Adamawa State, Northeastern Nigeria

Background and Objectives Despite the proven benefit of vaccines, the child immunization rate has been stagnant and the rate in African countries lags behind other regions in the world. For example, the global coverage of three doses diphtheria-tetanus-pertussis (DPT3) has been stagnant at 85% since 2015, while DPT3 coverage in Africa remains at 72% since 2010. The distribution of unvaccinated children is unequal; out of about 20 million infants who are not fully vaccinated, more than 20 percent of them reside in three countries, including Nigeria, the proposed study site. Furthermore, Nigeria is one of the few countries where the coverage of DPT3 coverage has decreased over time: 54 percent in 2010 to 42 percent in 2017.

Child immunization is not a one-time behavior; rather, it is a repeated behavior within a specific timeframe. Not only the low immunization, but also the dropout of immunization and the delayed immunization from the recommended immunization schedule are prevalent and high in Africa. The most common reason for the incomplete vaccination is that caregivers thought the children had already been fully immunized (44.8%), according to Nigeria Multiple Indicator Cluster Survey (MICS) conducted in 2016/2017.

Caregivers' misconception of the complete immunization can be attributed to the complicated immunization schedule. Each type and dose of vaccine has its own significance in terms of the type of preventable disease and the achievable efficacy level. In Nigeria, infants are supposed to receive 9 different types of vaccines at 5 different times within the first year since the births. For example, oral poliovirus vaccine (OPV) is to protect infants from contracting polio, a highly contagious disease. At present, Nigeria is one of the three countries in the world, which have not eliminated polio. Infants are scheduled to receive OPV four times; at birth, 6, 10, and 14 weeks. The efficacy of the first dose OPV (oral polio vaccine) is 82%, while the second and the third doses are 90% and 99% or more, respectively. To make things more complicated, the vaccine schedule changes over time; for example in Nigeria, the new vaccine, inactivated polio vaccine (IPV) was introduced in 2015 to be received at 14 weeks after births, and rotavirus vaccine and meningococcal A vaccine are scheduled for the introduction in 2019.

In this complicated and rapidly-changing environment regarding vaccination schedule, the goal of the study is to improve the understanding of vaccination completion and children's vaccination status among caregivers, which can then lead to the improved rate of full vaccination among children.

Objectives The main objectives of this study are to understand the impact of providing the general and tailored information on the vaccination schedule and vaccination status of women's children on the vaccine take-up. This study focuses on women who has a child who is 12 months old or younger.