An alternative to airborne droplet transmission route of SARS-CoV-2, the feco-oral route, as a factor shaping COVID-19 pandemic

The Chinese scenario, a rapid increase in the frequency of SARS-CoV-2 infections and sudden decline, is uncommon worldwide. Enormous differences in COVID-19 severity among individual countries are the striking findings of the pandemics. It has been demonstrated that a mild course of COVID-19 is associated with gastrointestinal symptoms, less inflammatory response, and better prognosis. The presence of SARS-CoV-2 was observed longer in the gastrointestinal tract than in respiratory swabs, promoting feco-oral transmissions and mild virus attenuation. The spread of the pandemic and its severity might, consequently, depends on the dominant environmental route of infection and emerging immunity. We hypothesize that the feco-oral SARS-CoV-2 transmission may help to achieve the long-term immunity against COVID-19, since it enables the continuous contact with viral antigens in the gastrointestinal tract, resulting in lower mortality rate. To conclude, countries producing rice through traditional methods developed rapidly emerging long-lasting population immunity, possibly through increased SARS-CoV-2 antigen exposure in the gastrointestinal tract. Our hypothesis brings attention to this potential route of herd immunity against SARS-CoV-2 which warrants further investigation in the future.