Countries with high deaths due to flu and tuberculosis demonstrate lower COVID-19 mortality: roles of vaccinations

Figures & data

Figure 1. COVID-19 deaths/million negatively correlates with Flu deaths at all three time points studied: Correlation of Flu deaths/100,000 was performed of countries for three different time points: 17^th May 2020 (a), 1^st October 2020 (b) and 31^st December 2020 (c) with respect to COVID-19 deaths/million. The graphs have been correlated and the Spearman’s correlation coefficient value (R_s) has been calculated along with the respective p values. Correlation has been considered statistically significant if p < .1

Figure 2. COVID-19 deaths/million negatively correlates with TB incidences at all three time points studied: Correlation of TB incidences was performed for countries at three different time points: 17^th May 2020 (a), 1^st October 2020 (b) and 31^st December 2020 (c) with respect to COVID-19 deaths/million. The graphs have been correlated and the Spearman’s correlation coefficient value (R_s) was calculated along with the respective p values. Correlation has been considered statistically significant if p < .1

Figure 3. TB deaths correlates with COVID-19 deaths/million negatively at all three time points studied: Correlation of deaths/100,000 due to TB was performed for countries at three different time points: 17^th May 2020 (a), 1^st October 2020 (b) and 31^st December 2020 (c) with respect to COVID-19 deaths/million. The graphs have been correlated and the Spearman’s correlation coefficient value (R_s) and the respective p values have been mentioned. Correlation has been considered statistically significant if p < .1

Figure 4. Countries having low TB and Flu deaths display the highest COVID-19 deaths/million: Countries were grouped based on the extent of Flu and TB deaths/100,000 and analyzed for COVID-19 deaths/million. The countries were divided into three groups by keeping a cutoff in which countries having >25 deaths/100,000 were considered as high deaths and denoted as ‘hi’ whereas countries having <25 deaths/100,000 were denoted as ‘lo’. The three groups were analyzed for mean differences at three different time points: (a). 17^th May 2020, (b). 1^st October 2020 and (c). 31^st December 2020. One-way ANOVA was used to calculate the statistical significance, *p < .05

Figure 5. COVID-19 deaths/million positively correlates significantly with Flu vaccination coverage at all three time points studied: Correlation of Flu vaccination coverage was performed for countries at three time points: 17^th May 2020 (a), 1^st October 2020 (b) and 31^st December 2020 (c) with respect to COVID-19 deaths/million. The graphs have been correlated and the Spearman’s correlation coefficient value (R_s) was calculated along with the respective p values. Correlation has been considered statistically significant if p < .1

Figure 6. BCG coverage negatively correlates with COVID-19 deaths/million at all three time points studied: BCG coverage was correlated for countries at three different time points: 17^th May 2020 (a), 1^st October 2020 (b) and 31^st December 2020 (c) with respect to COVID-19 deaths/million. Spearman’s correlation coefficient value (R_s) and the respective p values have been mentioned for each graph. Correlation has been considered statistically significant if p < .1

Figure 7. Countries belonging to the group of BCG⁺FluVac⁻ display the lowest COVID-19 deaths/million and the most delayed transmission of infection: Countries were grouped based on the coverage of BCG and flu vaccination and analyzed for COVID-19 deaths/million and COVID-19 mortality rate. These vast majority of countries were divided into four groups firstly based on the availability or non-availability of BCG or flu vaccination, designated with ‘+’ and ‘-‘ respectively. Next, the groups were further classified based on the extent of coverage of a particular vaccination. Countries with >50% coverage of a particular vaccination were considered having high vaccination and denoted with ‘hi’ whereas countries with <50% coverage were considered having low vaccination coverage and thus denoted ‘lo’. The four major groups were analyzed for mean differences at three different time points: (a). 17^th May 2020, (b). 1^st October 2020. and (c). 31^st December 2020. (d). The major groups out of 83 countries were also compared with respect to the time required for the first 10,000 cases to occur. One-way ANOVA was used to calculate the statistical significance, *p < .05 **p < .01, ***p < .001 and ****p < .0001

Figure 8. Countries with high BCG and high TB deaths show the lowest COVID-19 deaths/million: Countries with BCG coverage and TB deaths were further classified based on the extent of vaccine coverage and deaths/100,000. The two major groups were: BCG^hiTB^hi and BCG^hiTB^lo. The data was plotted based on COVID-19 deaths/million for (a). 17^th May 2020, (b). 1^st October 2020 and (c). 31^st December 2020. Unpaired t test was used to calculate statistical significance, *p < .05 and ****p < .0001

Figure 9. A model depicting the roles of vaccination and pathogen exposure on COVID-19 induced mortality: Countries having a vaccine providing broader protection, such as BCG, along with continuous exposure to pathogens provides effective cross immunity and thus lowers the numbers of COVID-19 induced deaths. It is possible that this combination will increase protection against newer pathogens in the future