The University of Babylon and Covid-19

COVID-19 is an infectious disease caused by the SARS-CoV-2 virus, which spreads among people in many different ways. The virus can spread from an infected person’s mouth or nose in small liquid particles when they cough, sneeze, speak, sing or breathe. These particles range from larger respiratory droplets to smaller aerosols. You can be infected by breathing in the virus if you are near someone who has COVID-19, or by touching a contaminated surface and then your eyes, nose or mouth. The virus spreads more easily indoors and in crowded settings. Current evidence suggests that the virus spreads mainly between people who are in close contact with each other, for example at a conversational distance. Another person can contract the virus when infectious particles that pass through the air are inhaled at short range (this is often called short-range aerosol or short-range airborne transmission) or if infectious particles come into direct contact with the eyes, nose, or mouth (droplet transmission). The virus can also spread in poorly ventilated and/or crowded indoor environments, where people tend to spend longer periods of time. This is because aerosols can remain suspended in the air or travel farther than conversational distance (one meter). Further research is ongoing to better understand the spread of the virus and which settings are most risky. Research is also under way to study virus variants that are emerging and why some are more transmissible. For updated information on SARS-CoV-2 variants, click here.

Whether or not they have symptoms, infected people can be contagious and the virus can spread from them to other people. Laboratory data suggests that infected people appear to be most infectious just before they develop symptoms (namely 2 days before they develop symptoms) and early in their illness. People who develop severe disease can be infectious for longer. While someone who never develops symptoms can pass the virus to others, it is still not clear how frequently this occurs and more research is needed in this area.