Coronaviruses are a large family of viruses that can cause illness in animals and humans. They are common in many different species of animals, including camels, cattle, cats, and bats. In humans, coronaviruses can cause mild respiratory infections like the common cold, as well as more severe illnesses like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). The most recently discovered coronavirus, SARS-CoV-2, is responsible for the COVID-19 pandemic that began in late 2019. COVID-19 is a highly contagious respiratory illness that can cause severe symptoms in some individuals, especially those with underlying health conditions or older adults. Research on coronaviruses focuses on understanding their genetic makeup, transmission dynamics, and immune response in order to develop treatments and vaccines to combat their spread and impact on public health. This includes studying how the virus infects cells, how it is transmitted between individuals, and how the immune system responds to infection.