The abundance of a specific intestinal bacteria known to suppresses the binding of the coronavirus to human cell receptors is likely to play a role in the low COVID-19 mortality rates seen in Asia and Northern Europe, according to a study led by a team of researchers at Nagoya University.
Many scientists have speculated there may be an X-factor when it comes to the low death rates from COVID-19 in Asia, including Japan, and some countries in Northern Europe such as Finland. Genetic and immunological differences, as well as the taking of the BCG vaccine in early childhood to protect against tuberculosis, have often been cited as possible reasons. An in-vitro study by the Kyoto Prefectural University of Medicine has also shown that compounds in green tea known as catechins significantly reduced the infectiousness of the coronavirus.
The highly contagious omicron variant is known to lead to less serious cases than the delta variant, and the mortality rate has been lowered to be more or less comparable to that of influenza.