The Influence of Bacille Calmette-Guerin Vaccine Strain on the Immune Response against Tuberculosis A Randomized Trial
ABSTRACT Approximately 100 million doses of bacille Calmette-Guérin (BCG) vaccine are given each year to protect against tuberculosis (TB). More than 20 genetically distinct BCG vaccine strains are in use worldwide. Previous studies suggest that BCG vaccine strain influences the immune response and protection against TB. Current data on which BCG vaccine strain induces the optimal immune response in humans are insufficient.
To compare the immune response to three different BCG vaccine strains given to infants at birth.
Newborn infants in a tertiary women's hospital were immunized at birth with one of three BCG vaccine strains. A stratified randomization according to the mother's region of birth was used.
The presence of mycobacterial-specific polyfunctional CD4 T cells measured by flow cytometry 10 weeks after immunization. Of the 209 infants immunized, data from 164 infants were included in the final analysis (BCG-Denmark, n = 54; BCG-Japan, n = 54; BCG-Russia, n = 57). The proportion of polyfunctional CD4 T cells was significantly higher in infants immunized with BCG-Denmark (0.013%) or BCG-Japan (0.016%) than with BCG-Russia (0.007%) (P = 0.018 and P = 0.003, respectively). Infants immunized with BCG-Japan had higher concentrations of secreted Th1 cytokines; infants immunized with BCG-Denmark had higher proportions of CD107-expressing cytotoxic CD4 T cells.
There are significant differences in the immune response induced by different BCG vaccine strains in newborn infants. Immunization with BCG-Denmark or BCG-Japan induced higher frequencies of mycobacterial-specific polyfunctional and cytotoxic T cells and higher concentrations of Th1 cytokines. These findings have potentially important implications for global antituberculosis immunization policies and future tuberculosis vaccine trials.
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ABSTRACT: In 2012, new publications in the Journal described both the predictive value of the new IFN-γ release assays for diagnosis of latent tuberculosis (TB), but also provided evidence that these new tests cannot be interpreted simply as positive or negative, as initially hoped. Surgical masks can reduce transmission of TB infection, but other measures such as state-wide implementation of targeted testing and treatment of latent TB or active case finding require substantial and sustained effort to successfully reduce TB morbidity and mortality. A quasiexperimental study revealed that a package of social interventions could substantially reduce risk of TB disease in heavily exposed (and infected) children in the preantibiotic era. A study in a high-TB burden setting suggested that a new rapid drug-susceptibility test for TB may be more practical for implementation than traditional culture-based phenotypic tests. And two studies of TB vaccines revealed that currently used bacillus Calmette-Guérin strains vary in their ability to affect correlates of immunogenicity, whereas a new candidate vaccine, MVA85A, was safe and immunogenic in adults. Studies of nontuberculous mycobacteria (NTM) described a rapid rise in the prevalence and spatial clustering of NTM in the United States over the past decade. Although risk factors for pulmonary NTM such as advanced age and low BMI are known, the mechanisms underlying infection and disease remain mysterious. Four studies of therapy of NTM disease highlighted the pressing need for well-designed international randomized controlled trials to improve our management of NTM disease.American Journal of Respiratory and Critical Care Medicine 07/2011; 184(2):180-5. DOI:10.1164/rccm.201102-0325UP · 11.99 Impact Factor
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ABSTRACT: Except during a 1-year period when BCG vaccine was not routinely administered, annual coverage of infants with Bacillus Calmette-Guérin (BCG) in Kazakhstan since 2002 has exceeded 95%. BCG preparations from different sources (Japan, Serbia, and Russia) or none were used exclusively in comparable 7-month time-frames, September through March, in 4 successive years beginning in 2002. Our objective was to assess relative effectiveness of BCG immunization. We compared outcomes of birth cohorts from the 4 time-frames retrospectively. Three cohorts received vaccine from one of three manufacturers exclusively, and one cohort was not vaccinated. Cohorts were followed for 3 years for notifications of clinical TB and of culture-confirmed TB, and for 21 months for TB meningitis notifications. Prevention effectiveness based on relative risk of TB incidence was calculated for each vaccinated cohort compared to the non-vaccinated cohort. Although there were differences in prevention effectiveness observed among the three BCG vaccines, all were protective. The Japanese vaccine (currently used in Kazakhstan), the Serbian vaccine, and the Russian vaccine respectively were 69%, 43%, and 22% effective with respect to clinical TB notifications, and 92%, 82%, and 51% effective with respect to culture confirmed TB. All three vaccines were >70% effective with respect to TB meningitis. Potential limitations included considerations that 1) the methodology used was retrospective, 2) multiple risk factors could have varied between cohorts and affected prevention effectiveness measures, 3) most cases were clinically diagnosed, and TB culture-positive case numbers and TB meningitis case numbers were sparse, and 4) small variations in reported population TB burden could have affected relative risk of exposure for cohorts. All three BCG vaccines evaluated were protective against TB, and prevention effectiveness varied by manufacturer. When setting national immunization policy, consideration should be given to prevention effectiveness of BCG preparations.PLoS ONE 03/2012; 7(3):e32567. DOI:10.1371/journal.pone.0032567 · 3.53 Impact Factor
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ABSTRACT: Reduction of active disease by preventive therapy has the potential to make an important contribution towards the goal of tuberculosis (TB) elimination. This report summarises discussions amongst a Working Group convened to consider areas of research that will be important in optimising the design and delivery of preventative therapies. The Working Group met in Cape Town on 26th February 2012, following presentation of results from the GC11 Grand Challenges in Global Health project to discover drugs for latent TB.Tuberculosis (Edinburgh, Scotland) 07/2012; 92(6):447-52. DOI:10.1016/j.tube.2012.06.004 · 3.50 Impact Factor