LAUSR

INTRODUCTION BCG is the only licensed vaccine against tuberculosis (TB) and, in Brazil, comprises part of the recommended vaccine schedule within the first month of life. Due to a local manufacturing shortage of BCG Moreau, BCG Russia was introduced in 2017 by the Brazilian Ministry of Health. OBJECTIVE To evaluate differences in immune responses induced by BCG Moreau and BCG Russia in infants, in addition to scar formation. METHODS The present case series involved 15 healthy infants who were vaccinated within the first seven days of life with one of two strains of BCG, then followed for 12 weeks or longer. Cytokine levels were measured before and after vaccination in whole blood culture supernatants previously stimulated in vitro with either BCG strain, heat-killed M. tuberculosis H37Rv or in the absence of stimulation. BCG scarring was also documented. RESULTS Infants vaccinated with BCG Moreau exhibited increased background IL-2, IL-10 and IL-4 production, yet no differences were found in those vaccinated with BCG Russia. Although both strains induced higher levels of IL-2 and IFN-γ, elevated IL-6, TNF and IL-10 production was also seen in response to BCG Russia. In contrast, no specific responses were observed against heat-killed M. tuberculosis H37Rv, with the exception of increased IL-2 following BCG Moreau vaccination. Although documented in both groups, scarring was milder and less frequent following BCG Russia vaccination. CONCLUSIONS Similar Th1 profiles were found following immunization with either type of BCG vaccine evaluated herein, with more pronounced cytokine production detected in response to the Russia strain. Overall, vaccination was well-tolerated and scarring evolved as expected for both BCG strains.