Association between Bacillus Calmette-Guérin vaccination and lymphoma: a population-based birth cohort study

BCG Vaccination: A potential tool against COVID-19 and COVID-19-like Black Swan incidents

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease 2019 (COVID-19), and its variants have brought unprecedented impacts to the global public health system, politics, economy, and other fields. Although more than ten COVID-19 specific vaccines have been approved for emergency use, COVID-19 prevention and control still face many challenges. Bacille Calmette–Guérin (BCG) is the only authorized vaccine used to fight against tuberculosis (TB), it has been hypothesized that BCG may prevent and control COVID-19 based on BCG-induced nonspecific immune responses. Herein, we summarized: 1) The nonspecific protection effects of BCG, such as prophylactic protection effects of BCG on nonmycobacterial infections, immunotherapy effects of BCG vaccine, and enhancement effect of BCG vaccine on unrelated vaccines; 2) Recent evidence of BCG's efficacy against SARS-COV-2 infection from ecological studies, analytical analyses, clinical trials, and animal studies; 3) Three possible mechanisms of BCG vaccine and their effects on COVID-19 control including heterologous immunity, trained immunity, and anti-inflammatory effect. We hope that this review will encourage more scientists to investigate further BCG induced non-specific immune responses and explore their mechanisms, which could be a potential tool for addressing the COVID-19 pandemic and COVID-19-like “Black Swan” events to reduce the impacts of infectious disease outbreaks on public health, politics, and economy.

Vaccination History and Risk of Lymphoma and Its Major Subtypes

BACKGROUND

Vaccinations have been hypothesized to play a role in lymphoma etiology, but there are few studies, mixed results, and limited data on lymphoma subtypes. Herein, we investigate the association of vaccinations with risk of major lymphoma subtypes.

METHODS

We studied 2,461 lymphoma cases and 2,253 controls enrolled from 2002 to 2014. Participants self-reported history of vaccinations against hepatitis A, hepatitis B, yellow fever, and influenza. Polytomous logistic regression was used to estimate OR and 95% confidence intervals (CI), adjusting for potential confounders.

RESULTS

After multivariable adjustment, vaccination against influenza was inversely associated with lymphoma (OR = 0.82; 95% CI, 0.66-1.02), which was stronger for last vaccination 1+ years before enrollment (OR = 0.71; 95% CI, 0.56-0.91) and for >5 influenza vaccinations (OR = 0.56; 95% CI, 0.46-0.68). Ever vaccination against hepatitis A (OR = 0.81; 95% CI, 0.66-1.00) but not hepatitis B (OR = 0.97; 95% CI, 0.81-1.18) was associated with lymphoma risk, although more recent vaccinations were inversely associated with lymphoma risk for both hepatitis A (<6 years before enrollment, OR = 0.56; 95% CI, 0.40-0.77) and hepatitis B (<9 years before enrollment, OR = 0.72; 95% CI, 0.55-0.93). Ever vaccination against yellow fever was inversely associated with risk (OR = 0.73; 95% CI, 0.55-0.96), and this did not vary by time since last vaccination. Although there was no overall statistical evidence for heterogeneity of vaccination history by lymphoma subtype, the only statistically significant inverse associations were observed for influenza and yellow fever vaccinations with diffuse large B-cell and follicular lymphoma.

CONCLUSIONS

Selected vaccinations were inversely associated with lymphoma risk, with time since last vaccination relevant for some of these vaccines.

IMPACT

Vaccinations against hepatitis A, hepatitis B, yellow fever, and influenza are unlikely to increase lymphoma risk.

Bacillus Calmette-Guerin 's beneficial impact on glucose metabolism: evidence for broad based applications

Bacillus Calmette-Guerin (BCG) vaccinations improve glycemic control in juvenile-onset Type I diabetes (T1D), an effect driven by restored sugar transport through aerobic glycolysis. In a pilot clinical trial, T1D, but not latent autoimmune diabetes of adults (LADA), exhibited lower blood sugars after multidose BCG. Using a glucose transport assay, monocytes from T1D subjects showed a large stimulation index with BCG exposures; LADA subjects showed minimal BCG-induced sugar responsiveness. Monocytes from T1D, type 2 diabetes (T2D), and non-diabetic controls (NDC) were all responsive in vitro to BCG by augmented sugar utilization. Adults with prior neonatal BCG vaccination show accelerated glucose transport decades later. Finally, in vivo experiments with the NOD mouse (a T1D model) and obese db/db mice (a T2D model) confirm BCG's blood-sugar-lowering and accelerated glucose metabolism with sufficient dosing. Our results suggest that BCG's benefits for glucose metabolism may be broadly applicable to T1D and T2D, but less to LADA.

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A pilot trial of BCG vaccinations to T1D showed reduced blood sugars but not in LADA

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Monocytes from T1D and to some degree T2D display stimulated glucose transport

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BCG vaccinations at birth show accelerated glucose transport decades later

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In vivo mouse models of both T1D and T2D demonstrate BCG-induced blood sugar lowering

Association between Bacillus Calmette-Guerin (BCG) vaccination and lymphoma risk: A systematic review and meta-analysis

Lymphoma etiology remains ill-defined, but immune factors seem to play a major role. The Bacillus Calmette-Guérin (BCG) vaccine, a non-specific stimulator of the cellular immune response, could influence lymphoma risk. Previous studies addressing this issue showed conflicting results. In this study, we performed a systematic review and meta-analysis to synthesize the epidemiological evidence. We conducted a systematic search of all relevant articles in PubMed, Embase, Library and Archives Canada, and Cochrane databases, up to November 1^st 2018. A total of 11 studies were included. Each study was summarized, methodological quality was assessed by independent evaluators, and a consensus score was generated. Heterogeneity and publication bias were evaluated. Summary odds ratios (ORs) and 95 % confidence intervals (CIs) were estimated separately for Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL) by either a fixed effect (FE) or a random effect (RE) model depending on heterogeneity. In this meta-analysis, BCG vaccination was not associated with HL (FE summary OR = 1.10; 95 % CI 0.93-1.30), but positively associated with NHL (RE summary OR = 1.20; 95 % CI 1.01-1.43). However, when restricting to higher quality studies, no association was found between BCG vaccination and either HL (RE summary OR = 0.97; 95 % CI 0.67-1.43) or NHL (RE summary OR = 1.15; 95 % CI 0.84-1.59). Overall, our findings do not support that BCG vaccination is associated with lymphoma risk. Yet, lack of statistical power and relatively high heterogeneity among studies prevent us from making definitive conclusions. Future studies investigating this issue are needed, using robust methodology.