Association between BCG vaccination and tuberculosis diagnosis: analysis by life stage and clinical characteristics

Abstract

Objective:  To  determine  the  association  between  BCG  vaccination  status  and  tuberculosis  diagnosis  across different life stages and clinical features in patients treated at the Dirección de Redes Integradas de Salud (DIRIS) Lima Sur from 2019 to 2022.

Materials and Methods: This cross-sectional study used secondary data from the Sistema de Información Gerencial de Tuberculosis (SIGTB). A census sampling approach was employed, incorporating records from 2019 to 2022. Absolute and relative frequencies were calculated, and Chi-square (χ²) tests were used for  comparisons.  Logistic  regression  analysis  was  conducted  to  evaluate  associations  among  variables,  and Odds Ratios (OR) were computed.

Results: The study included a total of 8,298 participants. No significant association was found between BCG  vaccination  and  the  occurrence  of  extrapulmonary  tuberculosis  (EPTB)  (OR  =  0.92;  95%  CI  =  0.81–1.05;  p  =  0.232)  or  pulmonary  tuberculosis  (PTB)  (OR  =  1.02;  95%  CI  =  0.99–1.05;  p  =  0.215).  These  findings  suggest  that  BCG  vaccination  does  not  confer  a  clear  protective  effect  in  the  analyzed  population.  However,  when  stratified  by  age,  BCG  vaccination  demonstrated  a  significant  protective  effect against EPTB in children under five years old (OR = 0.23; 95% CI = 0.13–0.42; p < 0.001).

Conclusions:  No  statistically  significant  association  was  identified  between  BCG  vaccination  and  the  presence  of  either  EPTB  or  PTB,  indicating  that  its  protective  effect  remains  inconclusive  in  the  general  study  population.  Nevertheless,  stratified  analysis  by  age demonstrated a significant protective effect of BCG vaccination against EPTB specifically in children under the age of five.