The Strange Case of BCG and COVID-19: The Verdict Is Still up in the Air

Spurious early ecological association suggesting BCG vaccination effectiveness for COVID-19

Background

Several ecologic studies have suggested that the bacillus Calmette-Guérin (BCG) vaccine may be protective against SARS-CoV-2 infection including a highly-cited published pre-print by Miller et al., finding that middle/high- and high-income countries that never had a universal BCG policy experienced higher COVID-19 burden compared to countries that currently have universal BCG vaccination policies. We provide a case study of the limitations of ecologic analyses by evaluating whether these early ecologic findings persisted as the pandemic progressed.

Methods

Similar to Miller et al., we employed Wilcoxon Rank Sum Tests to compare population medians in COVID-19 mortality, incidence, and mortality-to-incidence ratio between countries with universal BCG policies compared to those that never had such policies. We then computed Pearson’s r correlations to evaluate the association between year of BCG vaccination policy implementation and COVID-19 outcomes. We repeated these analyses for every month in 2020 subsequent to Miller et al.’s March 2020 analysis.

Results

We found that the differences in COVID-19 burden associated with BCG vaccination policies in March 2020 generally diminished in magnitude and usually lost statistical significance as the pandemic progressed. While six of nine analyses were statistically significant in March, only two were significant by the end of 2020.

Discussion

These results underscore the need for caution in interpreting ecologic studies, given their inherent methodological limitations, which can be magnified in the context of a rapidly evolving pandemic in which there is measurement error of both exposure and outcome status.

Unique Reciprocal Association Seen Between Latent Tuberculosis Infection and Diabetes Is Due to Immunoendocrine Modulation (DM-LTB-1)

Aim

The prevalence of latent tuberculosis infection (LTBI) among diabetes patients is poorly studied. In the present study, the prevalence of LTBI among pre-diabetes and diabetes patients was studied, along with immunoendocrine biomarkers (n = 804).

Methods

LTBI was screened by Quantiferon TB gold in Normal glucose tolerance [(NGT); n = 170, [Pre-diabetes (PDM; n = 209), Newly diagnosed diabetes (NDM; n = 165) and Known diabetes (KDM; n = 260) subjects. CRP, TNF-α, IL-6, IL-1β, IFN-β, IL-12, IFN-γ, IL-2, insulin, leptin, and adiponectin levels in serum and IFN-γ levels in quantiferon supernatants were quantified by ELISA. The expression of T-bet was quantified using qRT-PCR. Serum TBARS and nitrite levels were quantified by colorimetry.

Results

The LTBI prevalence was 32% in NGT, 23% in PDM, 24% in NDM, and 32% in KDM groups, with an adjusted OR of 0.61 (p < 0.05). Downregulation of CRP, TNF-α, and nitrites and upregulation of adiponectin could be responsible for LTBI mediated protection against insulin resistance (IR), while the high levels of IL-1β, IL-12, and leptin could be responsible for IR mediated anti-TB immunity. The defective antigen-specific IFN-γ response, as seen in the KDM group, could be responsible for the low detection rate of LTBI and high probability of endogenous reactivation.

Conclusion

There appears to be a biphasic relationship between diabetes-latent tuberculosis: At the early stages of diabetes it is reciprocal, while at a late stage it is synergistic, this important phenomenon obviously needs further research.

BCG vaccine to reduce healthcare worker absenteeism in COVID-19 pandemic, a randomized controlled trial

Objectives

The COVID-19 pandemic increases healthcare worker (HCW) absenteeism. The bacillus Calmette-Guérin (BCG) vaccine may provide non-specific protection against respiratory infections through enhancement of trained immunity. We investigated the impact of BCG vaccination on HCW absenteeism during the COVID-19 pandemic.

Methods

HCWs exposed to COVID-19 patients in nine Dutch hospitals were randomized to BCG vaccine or placebo in a 1:1 ratio, and followed for one year using a mobile phone application. The primary endpoint was the self-reported number of days of unplanned absenteeism for any reason. Secondary endpoints included documented COVID-19, acute respiratory symptoms or fever. This was an investigator-funded study, registered at ClinicalTrials.gov (NCT03987919).

Results

In March/April 2020, 1511 HCWs were enrolled. The median duration of follow-up was 357 person-days (interquartile range [IQR], 351 to 361). Unplanned absenteeism for any reason was observed in 2.8% of planned working days in the BCG group and 2.7% in the placebo group (adjusted relative risk 0.94; 95% credible interval, 0.78–1.15). Cumulative incidences of documented COVID-19 were 14.2% in the BCG and 15.2% in the placebo group (adjusted hazard ratio (aHR) 0.94; 95% confidence interval (CI), 0.72–1.24). First episodes of self-reported acute respiratory symptoms or fever occurred in 490 (66.2%) and 443 (60.2%) participants, respectively (aHR: 1.13; 95% CI, 0.99–1.28). Thirty-one serious adverse events were reported (13 after BCG, 18 after placebo), none considered related to study medication.

Conclusions

During the COVID-19 pandemic, BCG-vaccination of HCW exposed to COVID-19 patients did not reduce unplanned absenteeism nor documented COVID-19.

Pneumococcal and Influenza Vaccination Rates and Pneumococcal Invasive Disease Rates Set Geographical and Ethnic Population Susceptibility to Serious COVID-19 Cases and Deaths

This study examines the relationship of pneumococcal vaccination rates, influenza, measles-mumps-rubella (MMR) diphtheria-tetanus-pertussis vaccinations (DTP), polio, Haemophilus influenzae type B (Hib), and Bacillus Calmette-Guerin (tuberculosis) vaccination rates to COVID-19 case and death rates for 51 nations that have high rates of COVID-19 testing and for which nearly complete childhood, at-risk adult and elderly pneumococcal vaccination data were available. The study is unique in a large number of nations examined, the range of vaccine controls, in testing effects of combinations of vaccinations, and in examining the relationship of COVID-19 and vaccination rates to invasive pneumococcal disease (IPD). Analysis of Italian regions and the states of the United States were also performed. Significant positive correlations were found between IPD (but not lower respiratory infections) and COVID-19 rates, while significant negative correlations were found between pneumococcal vaccination and COVID-19 rates. Influenza and MMR vaccination rates were negatively correlated with lower respiratory infection (LRI) rates and may synergize with pneumococcal vaccination rates to protect against COVID-19. Pneumococcal and influenza vaccination rates were independent of other vaccination rates. These results suggest that endemic rates of bacterial pneumonias, for which pneumococci are a sentinel, may set regional and national susceptibility to severe COVID-19 disease and death.

On BCG Vaccine Protection from COVID-19: A Review

Bacille Calmette-Guérin (BCG) vaccine has been globally used to protect infants against tuberculosis (TB) for about a century. This vaccine has been shown to provide some degree of non-specific protection from other respiratory tract infections. This advantage has encouraged researchers to investigate the potential protection of this vaccine from the coronavirus disease 2019 from different perspectives in the ongoing pandemic. In this study, we have comprehensively reviewed the latest articles on potential vaccine effectiveness of BCG on COVID-19 and summarized the possible impacts of the BCG against SARS-COV-2 in detail.

COVID-19: Why does disease severity vary among individuals?

The novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is responsible for the current pandemic, coronavirus disease 2019 (COVID-19). While all people are susceptible to the SARS-CoV-2 infection, the nature and severity of the disease vary significantly among individuals and populations. Importantly, reported disease burdens and case fatality rates differ considerably from country to country. There are, however, still uncertainties about the severity of the disease among individuals or the reason behind a more severe disease in some cases. There is a strong possibility that the severity of this disease depends on a complicated interaction between the host, virus, and environment, which leads to different clinical outcomes. The objective of this article is to point out the essential influential factors related to the host, virus, and environment affecting the clinical outcome of COVID-19.

COVID-19 preparedness: capacity to manufacture vaccines, therapeutics and diagnostics in sub-Saharan Africa

OBJECTIVE

The COVID-19 pandemic is a biosecurity threat, and many resource-rich countries are stockpiling and/or making plans to secure supplies of vaccine, therapeutics, and diagnostics for their citizens. We review the products that are being investigated for the prevention, diagnosis, and treatment of COVID-19; discuss the challenges that countries in sub-Saharan Africa may face with access to COVID-19 vaccine, therapeutics, and diagnostics due to the limited capacity to manufacture them in Africa; and make recommendations on actions to mitigate these challenges and ensure health security in sub-Saharan Africa during this unprecedented pandemic and future public-health crises.

MAIN BODY

Sub-Saharan Africa will not be self-reliant for COVID-19 vaccines when they are developed. It can, however, take advantage of existing initiatives aimed at supporting COVID-19 vaccine access to resource-limited settings such as partnership with AstraZeneca, the Coalition for Epidemic Preparedness and Innovation, the Global Alliance for Vaccine and Immunisation, the Serum Institute of India, and the World Health Organization's COVID-19 Technology Access Pool. Accessing effective COVID-19 therapeutics will also be a major challenge for countries in sub-Saharan Africa, as production of therapeutics is frequently geared towards profitable Western markets and is ill-adapted to sub-Saharan Africa realities. The region can benefit from pooled procurement of COVID-19 therapy by the Africa Centres for Disease Control and Prevention in partnership with the African Union. If the use of convalescent plasma for the treatment of patients who are severely ill is found to be effective, access to the product will be minimally challenging since the region has a pool of recovered patients and human resources that can man supportive laboratories. The region also needs to drive the local development of rapid-test kits and other diagnostics for COVID-19.

CONCLUSION

Access to vaccines, therapeutics, and diagnostics for COVID-19 will be a challenge for sub-Saharan Africans. This challenge should be confronted by collaborating with vaccine developers; pooled procurement of COVID-19 therapeutics; and local development of testing and diagnostic materials. The COVID-19 pandemic should be a wake-up call for sub-Saharan Africa to build vaccines, therapeutics, and diagnostics manufacturing capacity as one of the resources needed to address public-health crises.

Current State of the First COVID-19 Vaccines

SARS CoV-2 and its associated disease COVID-19 has devastated the world during 2020. Masks and social distancing could be efficient if done by large proportions of the population, but pandemic fatigue has decreased their efficacy. Economic shut downs come with large price tags and cannot be a long term solution either. The announcements by three vaccine manufacturers in November that their vaccines are 90% or more effective has given hope to at least those in the population who plan to get vaccinated as soon as a scientifically and medically sound vaccine becomes available. This review summarizes the underlying design strategies and current status of development of the nine vaccines that were in phase III trial on 8 November 2020. Contracts between vaccine manufacturing companies and governments aim at distributing the vaccine to a large part of the world population. Questions remain how the temperature sensitive mRNA vaccines will be transported and/or stored and how vaccination will be prioritized within each country. Additionally, current contracts do not cover all countries, with a serious gap in Africa and South America. The second part of this review will detail current distribution plans and remaining challenges with vaccine accessibility and acceptance.