As of now, breaking the transmission chain through lockdown is the route most countries have taken recourse to. The medical community is researching whether contracting the virus makes people immune to it in the long term — as is the case with measles.  Some recovered Covid-19 patients have relapsed. A vaccine is 12-18 months away but, in the interim, lockdown cannot be a one-size-fits-all approach. The Spanish Flu circled the world from 1918 to 1920; there were three waves of the pandemic, with the third one accounting for 8 per cent of the overall deaths.