Objectives Regarding Severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2), it is known that a substantial percentage of the adult population do not become infected when exposed to this novel coronavirus. Several studies provide an initial indication of the possible role of preexisting 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/100,000 population standardized to BCG coverage rates was taken as a direct factor in the test. Malaria incidence/1000 population was considered as an intermediate factor. The outcome was COVID-19 mortality/million (M) 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.
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.
Background: It is well known that COVID-19 vaccines demonstrate higher efficacy against mortality than mild acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The estimation of the proportion of mortalities among morbidities is a measure of the case fatality risk (CFR). To date, few studies have estimated the real-world CFR in relation to COVID-19 vaccination coverage. This study aims to evaluate the change in CFR estimates among different countries following the introduction of COVID-19 vaccines, and to identify the threshold dose of vaccines that changed the CFR as early as April 3, 2021. Furthermore, this study sheds light on the influence of COVID-19 vaccinations on the attack rate (AR), death rate, and, ultimately, CFR. Material and Methods: We collected publicly available data concerning all countries and territories that implemented COVID-19 vaccination at least for 100 days, with an end date of April 3, 2021. In total, we found 16 countries and territories. The CFR was measured as the number of deaths per 100 COVID-19 confirmed cases, while vaccine coverage was defined as the number of doses of vaccine per 100 people in the total population. We performed descriptive data analyses, including the mean value, standard deviation, and graphical presentation, using bar charts. Performed inferential data analyses included the one-sample Kolmogorov–Smirnov (K-S) test and general linear model procedure (GLM). Results: Our findings showed a significantly associated decrease in the mean CFR in countries with > 18 COVID-19 vaccine doses per 100 inhabitants. We found a decrease from 1.88 % to 1.45 % with a (p-value =0.03), indicating a decrease in the proportion of total deaths to total cases. There was a decrease in the 95% confidence interval from 0.742-3.006 to 0. 718-2.179. The decrease in CFR was greater among the total deaths than total cases. Conclusion: COVID-19 vaccination was found to decrease the COVID-19- CFR. Recommendations: Post-interventional CFR monitoring may constitute a parameter for measuring vaccination effectiveness and progress of the current pandemic or future pandemics. Furthermore, post-interventional CFR estimates can be used as a parameter for assessment effectiveness of interventions e.g. COVID-19 vaccination effectiveness.
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