You've found the only sentence in the entire article about vaccination and attached you own meaning to it. If Ardheli wished to convey that severe disease increased the risk of complications much more than mild disease Ardheli could have and should have stated so.

I'm not saying your point is invalid, I'm just saying it's not addressed in the article in question. Please be more careful. It's OK to just admit you we're wrong. It's not OK to twist quotations to support your position not matter how valid or righteous you believe it to be.