Coronavirus is a VIRUS. More precisely, it’s a family of viruses that cause everything from the common cold to various kinds of flu to deadly illnesses like the SARS outbreak of 2003 and more recently MERS. The coronavirus we’re dealing with right now is technically called SARS-CoV-2. You’ve heard it called a “novel coronavirus”. “Novel” here means “new”, not “curious” or “interesting”.
COVID-19 is a DISEASE that’s caused by this particular coronavirus. It’s a respiratory disease, meaning it attacks the lungs. There’s currently no vaccine and no cure for it (it’s “novel”, remember?). You have no natural immunity to it,for the same reason. Your body will attempt to fight it off and in many cases it will be successful. But if you’re older or have underlying health issues, you may need to be hospitalised, perhaps in intensive care and even on a ventilator when your lungs can no longer breathe.