Neonatal BCG vaccination reduces interferon gamma responsiveness to heterologous pathogens in infants from a randomised controlled trial

Background Bacille Calmette-Guérin (BCG) vaccination has beneficial non-specific (heterologous) effects that protect against non-mycobacterial infections. We have previously reported that BCG vaccination at birth alters in vitro cytokine responses to heterologous stimulants in the neonatal period. This study investigated heterologous responses in 167 infants in the same trial seven months after randomisation. Methods A whole blood assay was used to interrogate in vitro cytokine responses to heterologous stimulants (killed pathogens) and Toll-like receptor (TLR) ligands. Results Compared to BCG-naïve infants, BCG-vaccinated infants had increased production of MIG and IFN-γ in response to mycobacterial stimulation and decreased production of IFN-γ in response to heterologous stimulation. Reduced IFN-γ responses to heterologous stimulants and TLR ligands were attributable to a decrease in the proportion of infants who mounted a detectable IFN-γ response. BCG-vaccinated infants also had increased production of MIG and IL-8, and decreased production of IL-10, MIP-1α and MIP-1ß, the pattern of which varied by stimulant. IL-1Ra responses following TLR1/2 (Pam3CYSK4) stimulation were increased in BCG-vaccinated infants. Both sex and maternal BCG vaccination status influenced the effect of neonatal BCG vaccination. Conclusions BCG vaccination leads to changes in IFN-γ responsiveness to heterologous stimulation. BCG-induced changes in other cytokine responses to heterologous stimulation varies by pathogen

Neonatal BCG Vaccination Influences Cytokine Responses to Toll-like Receptor Ligands and Heterologous Antigens

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Comparable CD4 and CD8 T cell responses and cytokine release after at-birth and delayed BCG immunisation in infants born in Australia

BackgroundMore than 120 million doses of BCG vaccine are administered worldwide each year. Most infants are given BCG at birth in accordance with WHO recommendations. However, the effect of the maturing neonatal immune system on the immune response and protection conferred by BCG remains uncertain. Previous studies investigating the influence of age at immunisation on the immune response induced by BCG have reported conflicting results. This study compared BCG given at birth and at two months of age in infants in Australia.MethodsInfants born in Melbourne were randomly allocated to immunisation with BCG-Denmark at birth or two months of age. Ten weeks after immunisation, anti-mycobacterial immune responses were measured in a whole blood assay using intracellular cytokine assays and xMAP multiplex cytokine analysis.ResultsResult from 98 BCG-immunised infants were included in the final analysis. BCG immunisation at birth (n = 54) and at 2 months of age (n = 44) induced comparable proportions of mycobacteria-specific cytokine-producing CD4 and CD8 T cells, as well as comparable proportions of polyfunctional (TNF+ IL-2+ IFN-?+) CD4 T cells. Concentrations of cytokines in supernatants were also similar in both groups.ConclusionsCellular immunity measured 10 weeks after BCG immunisation was similar in infants given BCG at birth and in those given BCG at 2 months of age. Although definitive correlates of protection against TB remain uncertain, these results suggest that delaying BCG immunisation does not confer any immunological advantage in cellular immunity

The influence of bacille Calmette-Guerin vaccine strain on the immune response against tuberculosis: a randomized trial

Rationale: 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.Objectives: To compare the immune response to three different BCG vaccine strains given to infants at birth.Methods: 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.Measurements and main results: 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.Conclusions: 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

Bacillus Calmette-Guérin Skin Reaction Predicts Enhanced Mycobacteria-Specific T-Cell Responses in Infants: A Post Hoc Analysis of a Randomized Controlled Trial

Rationale: Scar formation following bacillus Calmette-Guérin (BCG) vaccination has been associated with lower all-cause mortality; the relation between scar and mycobacteria-specific protection against tuberculosis is debated. Objectives: To evaluate the association between BCG skin reaction and mycobacteria-specific immune responses. Methods: Apost hocanalysis was done among 214 infants in Australia randomized to vaccination with one of three BCG vaccine strains (BCG-Denmark, BCG-Japan, or BCG-Russia) given at birth or BCG-Denmark given at 2 months of age. Measurements and Main Results: BCG skin reaction size and characteristics 10 weeks after vaccination were related to thein vitromycobacteria-specific immune responses measured in stimulated whole blood. The size and characteristics of the skin reaction correlated positively within vitroimmune responses, even after adjusting for BCG vaccine strain and age at vaccination. Specifically, the reaction size and characteristics correlated with the proportion of mycobacteria-specific polyfunctional CD4+T cells after stimulation with BCG and PPD and, to a lesser extent, after stimulation withMycobacterium tuberculosisorMycobacterium ulcerans. A similar correlation was observed with concentrations of IFN-γ, IL-2, tumor necrosis factor, and IL-13 in the supernatant after stimulation with BCG, PPD, andM. tuberculosisand to some degree for the proportions of mycobacteria-specific polyfunctional CD8+T cells and CD107+cytotoxic cells. Conclusions: BCG skin reaction correlated with the magnitude of mycobacteria-specific T-cell responses. As T-cell responses play a key role in defense against mycobacteria, the relationship between BCG scar formation and protection against tuberculosis should be revisited. This may also extend to the need for BCG revaccination in scar-negative individuals. Clinical trial registered with www.australianclinicaltrials.gov.au/clinical-trial-registries (ACTRN12608000227392).</p

Mycobacterium ulcerans-specific immune response after immunisation with bacillus Calmette-Guérin (BCG) vaccine

Background: Bacillus Calmette-Guérin (BCG) vaccine provides partial protection against Buruli ulcer caused by Mycobacterium ulcerans in epidemiological studies. This study aimed to quantify M. ulcerans-specific immune responses induced by BCG immunisation. Methods: Intracellular cytokine analysis of in-vitro experiments done 10 weeks after BCG immunisation in 130 Australian infants randomised to one of three BCG vaccine strains given either at birth (BCG-Denmark, BCG-Japan, or BCG-Russia) or at two months of age (BCG-Denmark). Results: Proportions of polyfunctional CD4+ T-cells were higher in M. ulcerans-stimulated compared to unstimulated control samples. These proportions were not influenced by the vaccine strain or timing of the immunisation. The M. ulcerans-specific immune responses showed similar patterns to those observed in M. tuberculosis-stimulated samples, although they were of lower magnitude. Conclusions: Our data show that BCG immunisation induces M. ulcerans-specific immune responses in infants, likely explaining the cross-protective effect observed in epidemiological studies. (ACTRN12608000227392)

Prevention of infant eczema by neonatal bacille Calmette-Guérin vaccination: The MIS BAIR randomized controlled trial

Background: Bacille Calmette-Guérin (BCG) vaccine could play a role in counteracting the rising prevalence of atopic diseases, through its beneficial off-target effects. We aimed to determine whether neonatal BCG vaccination reduces the incidence of eczema in infants.Methods: Randomized controlled trial with 1272 infants allocated to receive BCG-Denmark or no BCG at birth. The primary outcome was the 12-month incidence of eczema based on 3-monthly questionnaires. Eczema was also assessed at a 12-month clinic visit. ClinicalTrial.gov: NCT01906853.Results: The 12-month eczema incidence was 32.2% in the BCG group compared with 36.6% in the control group (adjusted risk difference (aRD) -4.3%, 95% CI -9.9% to 1.3%, multiple imputation model). In addition, comparing infants in the BCG group with the control group, 15.7% vs. 19.2% had eczema lesions at the 12-month visit (aRD -3.5%, 95% CI -8.0% to 1.0%); 35.7% vs. 39.0% reported using topical steroids (aRD -3.3, 95% CI -9.2 to 2.7); and 7.3% vs. 10.2% had severe eczema scores (aRD -3.0%, 95% CI -8.8% to 2.7%). In 344 high-risk infants (two atopic parents), the 12-month eczema incidence was 35.3% in the BCG group compared with 46.8% in the control group (aRD -11.5%, 95% CI -21.9% to -1.2%; number needed to treat 8.7, 95% CI 4.6 to 83.3).Conclusion: There is insufficient evidence to recommend neonatal BCG vaccination in all infants for the prevention of eczema in the first year of life; however, a modest beneficial effect was observed among high-risk infants. A single dose of BCG-Denmark soon after birth could reduce the incidence of eczema in infants with two atopic parents.</p

Feasibility and acceptability of targeted salivary cytomegalovirus screening through universal newborn hearing screening

Aim This study aimed to determine the feasibility and parental acceptability of screening for congenital cytomegalovirus (cCMV) through saliva polymerase chain reaction in infants who did not pass their newborn hearing screening. Additionally, the utility (i.e. time to diagnosis and treatment) of this enhanced clinical pathway was evaluated. Methods The study was conducted through the Victorian Infant Hearing Screening Programme (VIHSP) across four maternity hospitals in Melbourne, Australia, during June 2019–March 2020. Parents were approached by VIHSP staff about obtaining a test for cytomegalovirus (CMV) at the time of their baby's second positive (‘refer’) result on the VIHSP screen. Participating parents collected a saliva swab for CMV polymerase chain reaction from their infants. Feasibility was determined by the proportion of ‘referred’ infants whose parents completed the salivary CMV screening test ≤21 days of life. Acceptability was measured through parent survey. Results Of 126 eligible families, 96 (76.0%) had salivary screening swabs taken ≤21 days of life. Most families (>92.0%) indicated that screening was acceptable, straightforward and thought testing their baby for cCMV was a good idea. One infant screened positive on day 30, was diagnosed with cCMV via confirmatory testing by day 31 and commenced valganciclovir on day 32. Conclusions Obtaining a saliva sample to screen for cCMV in infants who do not pass their newborn hearing screen is feasible and appears acceptable to parents. This targeted cCMV screening method could be an option where mothers are rapidly discharged from hospital, especially in the context of the COVID-19 pandemic