Green Tea Consumption and the COVID-19 Omicron Pandemic Era: Pharmacology and Epidemiology

Abstract

In spite of the development of numerous vaccines for the prevention of COVID-19 and the approval of several drugs for its treatment, there is still a great need for effective and inexpensive therapies against this disease. Previously, we showed that green tea and tea catechins interfere with coronavirus replication as well as coronavirus 3CL protease activity, and also showed lower COVID-19 morbidity and mortality in countries with higher green tea consumption. However, it is not clear whether green tea is still effective against the newer SARS-CoV-2 variants including omicron. It is also not known whether higher green tea consumption continues to contribute to lower COVID-19 morbidity and mortality now that vaccination rates in many countries are high. Here, we attempted to update the information regarding green tea in relation to COVID-19. Using pharmacological and ecological approaches, we found that EGCG as well as green tea inhibit the activity of the omicron variant 3CL protease efficiently, and there continues to be pronounced differences in COVID-19 morbidity and mortality between groups of countries with high and low green tea consumption as of December 6, 2022. These results collectively suggest that green tea continues to be effective against COVID-19 despite the new omicron variants and increased vaccination.

Correlations betweenper capitagreen tea consumption and COVID-19 morbidity/mortality: comparing the strength before and after Omicron emergence

“…The values are coefficients of regression obtained in the multiple regression models accounting for the following confounding factors: population density, percentage of population aged above 65, percentage of urban population, and Human Developmental Index (HDI). See methods and [9] for more details. *, **, and *** indicate levels of statistical significance of these correlations: P<0.05, P<0.01 and P<0.001 respectively.…”

“…The information on ‘Worldometer’ is based on official reports and considered as a reliable (for instance, [12]. Analysis used in this report was similar to that described previously [7–9]. However, here the focus was on the strength of correlations between per capita green tea consumption and COVID-19 morbidity/mortality in a subset of countries/territories with HDI above 0.55 (n=84).…”

“…It should be noted that while strength of correlations between per capita green tea consumption and COVID-19 morbidity/mortality have been already reported for several dates before Omicron emergence [7, 8], these values cannot be directly compared to values reported more recently [9]. Indeed, subsets of countries used for multiple linear regression analysis were different: countries with HDI above 0.55 only [9], versus countries with HDI above and below 0.55 [7, 8]. Additionally, logarithm of per capita green tea consumption was used in multiple linear regression model in more recent work [9] while per capita green tea consumption itself was used in earlier works [7, 8].…”

“…Indeed, subsets of countries used for multiple linear regression analysis were different: countries with HDI above 0.55 only [9], versus countries with HDI above and below 0.55 [7, 8]. Additionally, logarithm of per capita green tea consumption was used in multiple linear regression model in more recent work [9] while per capita green tea consumption itself was used in earlier works [7, 8]. (Variables COVID-19 morbidity and COVID-19 mortality) were transformed to Log in all abovementioned ecological studies).…”

“…Unless otherwise noted COVID-19 morbidity and COVID-19 mortality referred in this report reflect cumulative data since the beginning of the epidemic to specified date. Though increases in COVID-19 morbidity and mortality for specified periods of time were also calculated (as described earlier [9] see also Supplementary Materials), this was done in complementary analysis to access possible bias of results due to vaccination.…”