As countries lie frozen in lockdown and billions of people lose their livelihoods, public figures are teasing a breakthrough that would mark the end of the crippling coronavirus pandemic: a vaccine.

But there is another, worst-case possibility: that no vaccine is ever developed. CNN reports that this possibility is taken very seriously by many experts — because it's happened several times before.

According to a CNN report, if that happens, instead of wiping out Covid-19, societies may instead learn to live with it.

Cities would slowly open and some freedoms will be returned.

Testing and physical tracing will become part of our lives in the short term, but in many countries, an abrupt instruction to self-isolate could come at any time.

Treatments may be developed — but outbreaks of the disease could still occur each year, and the global death toll would continue to tick upwards.

Read the full CNN report here.