Covid-19 (Coronavirus SARS-CoV-2; coronavirus disease 2019) is a virus that first appeared in China in 2019. The virus belongs to the strain of coronaviruses, which usually infect certain mammals or birds and normally only cause mild colds in humans. However, viruses can change (mutate) and adapt to new conditions. In the case of normal influenza viruses, experts are always assessing future mutations and developing vaccines before the start of the new influenza season to combat the most likely changes.
