A new study shows that the Bacillus Calmette-Guérin vaccine continues to have a protective effect against tuberculosis in adults decades after vaccination.
The study, which will was recently posted online and will be published in a World TB-related issue of the journal Thorax, may have important implications for national TB vaccination policies. Several articles in the same issue note that Mycobacterium tuberculosis is surprisingly adaptive, successful and currently has a rising incidence rate, according to Medscape.com
"BCG vaccine has a documented protective effect against [TB] meningitis and disseminated TB in children, and is used as a complementary strategy for TB control," Dr. Pei-Chun Chan and his colleagues from the Taiwan Centers for Disease Control and National Taiwan University said, Medscape.com
reports. "Greater than 80 percent of neonates and infants are covered by BCG in countries where the vaccine is part of the national childhood immunization program.
"However, the protective effect of BCG against pulmonary TB in previous studies remains controversial."
Dr. Pei-Chun Chan said that there were several limitations to his study, including its cross-sectional design, the use of the number of BCG scars as a proxy for BCG vaccination record and a possible birth cohort effect.
"Our results suggest that BCG vaccine seems to have a protective effect in adults decades after vaccination according to the number of recent infections," the study authors said, according to Medscape.com
. "This finding has important implications for national policy of BCG vaccination. Further prospective cohort studies on the protective effect of BCG vaccination against TB infection in adults are warranted."