Does SARS-Cov-2 Interfere with Other Viruses? Human Diseases Incidence Change is Observed

This research considers the hypothesis whether there are - and what they are - correlations between the COVI19 pandemic and changes in the incidence of other viral infections, for the purpose of subsequent applications. A novel Coronavirus is the causative agent of a disease named COVID-19. The disease, appeared in 2019, has already claimed around than 4.7 million lives and around 230 million infections worldwide as of 20th Sept. 2021 (https://www.worldometers.info/coronavirus). The etiologic agent virus was named SARS-CoV-2 (Severe Acute Respiratory Syndrome - Coronavirus - 2) and classified in the subgenus Sarbecovirus. A reduction in the incidence of other viral diseases, of huge geographical or planetary interest, seems to be accompanying the epidemics. Infections affected include seasonal flu, childhood exanthematous diseases, seasonal gastrointestinal viral infections, and even some vector-borne diseases, such as Dengue: their incidence is reduced to an extent sometimes exceeding 90%. Data out from countries are shown and discussed. The phenomenon, certainly complex, requires urgent and precise explanations. The hypothesis of an association with the containment measures implemented everywhere for Covid-19 was initially proposed, but this possible explanation appears feeble and not fully exhaustive; it is not equally distributed in each country, also considering extremely different aspects of virus morphology, pathogenesis and epidemiology of the viral diseases involved. The knowledge, both of the real reasons and of the trend of a possible reduction in the incidence of already endemic infections and of the possible health consequences that could follow, on the dimensions of the whole biome, is of impressive health and economic impact. New approaches to the prophylaxis and therapy of infectious diseases could be some of the most immediate consequence of the knowledge that can be acquired.