A group of physicians from the United States and Poland, led by professor at the University of Nevada at Reno (USA) Christopher von Bartheld, found significant ethnic differences in how SARS-CoV-2 acts on the nervous system. With COVID-19, Europeans suffer from a loss of smell and taste about 3-6 times more often than other inhabitants of the Earth. The findings were published in an article on medRxiv.
Scientists combined the data of all studies in the world, the authors of which studied the loss of taste and smell among carriers. After analyzing 42 studies in which more than 23 thousand patients with COVID-19 and healthy people of various nationalities participated, Von Bartheld and his colleagues combined their results and tried to find common patterns.
On the one hand, their analysis confirmed that the loss of smell and taste are indeed the most common early symptoms of coronavirus infection. Approximately 39% of patients lost their ability to recognize odors, and a loss of taste was characteristic of 30% of them. In total, more than 50% of patients developed at least one or both of these problems.
At the same time, scientists found that problems with smell and taste affected people of different ethnic backgrounds in different ways. For example, people of Asian descent or Afro-descendants suffered from these problems relatively rarely – they were characteristic only for 6-15% of them.
On the other hand, almost half of Europeans and Americans of European descent suffered from loss of smell (43%), and another 38% of them lost taste when infected with coronavirus.
According to scientists, such discrepancies are associated not with what strains of SARS-CoV-2 are distributed in different regions of the world, but with the genetic characteristics of each ethnic group. In particular, von Bartheld and his colleagues believe that the reason for this may be that the olfactory receptors of Europeans have more ACE2 molecules that the virus uses to enter cells. This, in turn, may explain why the COVID-19 epidemic spread much faster across Europe and the United States than it did in China and other Asian countries, scientists conclude.