Factors influencing post BCG vaccination scar formation amongst vaccinated children: a case study of a tertiary institution in Northeastern Nigeria.

Abstract Introduction: Bacille Calmette-Guerin (BCG) vaccination against tuberculosis has been shown to reduce TB incidence and improve child survival. The presence of a BCG scar following vaccination indicates an appropriate immune response and may be associated with lower child mortality. This study aims to assess the factors associated with BCG scarring in vaccinated children in Yola, Northeastern Nigeria. Materials and Methods: The study was descriptive and cross-sectional. Children were selected and physically examined for a BCG scar. Data were analysed using the Statistical Package for the Social Sciences software (SPSS). Chi-square test was used for the association between categorical variables. P < 0.05 was considered significant. Results: A total of 277 children were enrolled, 146(52.7%) were males and 131(47.3%) females, giving a male: female ratio of 1.1:1. The median age was 6 months and 160(57.8%) were aged less than six months. Of the 277 children, 259 had the BCG scar, giving a prevalence of 93.5%, and 18 were without a scar, giving a BCG scar failure prevalence of 6.5%. Of the factors related to BCG scars, only children on drugs (medications like antibiotics or analgesics) during administration of BCG vaccines were found to be statistically significant to BCG scarring (p value = 0.013).  Conclusion: The study demonstrated a high prevalence of BCG scars, and administering the BCG vaccine while children are on medications (analgesics or antibiotics) was significantly associated with BCG scar formation. We therefore recommend further studies to understand the observed association.