Influence of malaria endemicity and tuberculosis prevalence on COVID-19 mortality.

OBJECTIVES: Regarding severe acute respiratory syndrome coronavirus 2, it is known that a substantial percentage of the adult population does not become infected when exposed to this novel coronavirus. Several studies provide an initial indication of the possible role of pre-existing immunity, whether cross-immunity or not. The possible role of latent tuberculosis (TB) and malaria has been suggested to create innate cross heterogeneous immunity. In this study, we looked for the influence of these factors on coronavirus disease 2019 (COVID-19) mortality in malaria-endemic countries. STUDY DESIGN: Eighty malaria-endemic countries were enrolled in this cross-sectional study. Data subjected to testing included TB prevalence, Bacillus Calmette-Guérin (BCG) vaccine coverage, malaria incidence, and COVID-19 mortality. METHODS: Hierarchical multiple regression type of analysis was used for data analyses. TB prevalence per 100,000 population standardized to BCG coverage rates was taken as a direct factor in the test. Malaria incidence per 1000 population was considered an intermediate factor. The outcome was COVID-19 mortality per million population. RESULTS: The results showed with robust statistical support that standardized TB prevalence was significantly associated with reduced COVID-19 mortality. Malaria had an additional effect in reducing COVID-19 mortality, with a highly significant association. CONCLUSIONS: Malaria and standardized TB prevalence are statistically significant factors associated negatively with COVID-19 mortality.

Impact of duration of cessation of mass BCG vaccination programs on Covid -19 mortality

Background: BCG have heterogeneous immunity to certain pathogens other than Mycobacterium tuberculosis effect. At early times during COVID-19 pandemic heterogeneous immunity towards (SARS-CoV-2), was hypothesized and statistical correlation between of BCG vaccination practices and COVID-19 mortality variances among countries was statistically proved. These studies was criticized because of low evidence of such studies and possible confounding factors. For that reason this study was designed to look for impact of duration of cessation of BCG programs on Covid-19 mortality looking for the hypotheses by different design and looking forward to support previous studies. Methods: Total number of studied group is 14 countries which has stopped BCG vaccination programs. Through applying stem-leaf plot for exploring data screening behavior concerning Covid-19 Mortality for obsolescence duration of cessation of mass BCG vaccination programs, as well as (nonlinear regression of compound model) for predicted shape behavior for that group. Results: Slope value shows highly significant effectiveness of obsolescence of cessation of mass BCG vaccination programs on Covid -19 mortality at P-value<0.000. Obsolescence of duration of cessation of mass BCG vaccination programs has strongly negatively associated with Covid-19 mortality in countries which stopped BCG vaccination programs. Conclusion: The longer the cessation duration of BCG programs, the higher the Covid-19 mortality is, and vice versa.

Tuberculosis versus covid-19 mortality: A new evidence

BACKGROUND: Coronavirus current pandemic (COVID-19) is the striking subject worldwide hitting countries in an unexplained non-universal pattern. Bacillus Calmette–Guérin (BCG) vaccine was an adopted recent justification depending on its non-specific immune activation properties. Still the problem of post-vaccine short duration of protection needs to be solved. The same protective mechanism was identified in active or latent tuberculosis (TB). For each single patient of active TB, there are about nine cases of asymptomatic latent TB apparently normal individuals living within the community without restrictions carrying benefits of immune activation and involved in re-infection cycles in an excellent example of repeated immunity training sessions of the whole community. AIM: We aimed to asses the correlation between TB burden and COVID-19 mortality in all affected countries having different BCG vaccination policies. METHODS: Publicly available data were extracted for 191 countries including population size, TB estimations, national BCG vaccination policy, the World Health Organization regions and economic classification, and COVID-19 mortality and number of cases. The analysis was performed using Spearman’s correlation test. RESULTS: Significant large negative correlation (−0.539, p < 0.001) was found between TB prevalence and COVID-19 mortality rate worldwide. Medium negative significant correlations were found between TB cases and COVID-19 mortality in the high and lower middle-income countries, and those having current BCG vaccination programs (−0.395, p = 0.001, −0.365, p = 0.015, and −0.476, p < 0.001, respectively). CONCLUSION: Countries with high TB prevalence have higher chances of protection against COVID-19 mortality through the theory of widely distributed natural immune activation within community. Confounders should be assessed separately.