I spent 6 weeks on the "Free list" (an expectation to pass away) in Stepping Hill in 1958/59 after contracting it and was saved by a vaccine. The UK came through relatively unscathed with over 14,000 fatalities.
We may well come through this with minimal deaths but i would suggest the Governments reaction, plus those from other Governments around the World, indicates that the treat is more than just a scaremongering exercise.