It makes me wonder how the world would cope today with a Bubonic Plague or Spanish Flu, those two I reckon would probably be more similar to your hypothetical Sci-Fi disease.
On the Spanish Flu specifically, the evidence indicates most people who died were killed by secondary bacterial infection, not the virus itself[1]. This was the result of a combination of poor hygienic conditions and lack of antibiotics. Considering that, I think what we are witnessing with SARS-CoV-2 is about what the Spanish Flu would look like today.
Bubonic Plague is still around, quite deadly if untreated, antibiotics work if given quickly enough (and are used as a preventative measure for contact persons). Large outbreaks are rare.
[1] https://academic.oup.com/jid/article/196/11/1717/886065