I suggest you read the science kcockayne. The virus is a single strand of RNA that has only mutated once. It is amenable to vaccines. There are 9 leading projects using at least 5 different methods. We know patients often produce antibodies and we also now know that if re exposed the antibodies respond. All this suggests one or other vaccine will succeed and GAVI and the major players such as AZ and Sanofi are building capacity.
Separately there is possibly an evens chance the virus may simply disappear as did SARS and although we may get a resurgence of cases from easing lockdown too early, there is no evidence of the mythical second wave.
I would put money on a vaccine by Q4 and the end of new medical cases in 2021. The economic issues will take longer to resolve especially if idiots apply quarantine in June as opposed to February and scatter taxpayers' money to all and sundry instead of supporting those most effected.