Is smallpox serious?

Yes and no. It's extremely serious if you get it. But since the disease has been eradicated frm the planet, it 's not a serious concern.
Deadly. Case fatality rate 30-100% depending on form and patient age. Patients were often bedridden with fever 102-4 for the week before spots came out. If they survived, it was 3-4 wks before the were no longer contageous and longer before they regained their strength.