janipat Yes, I read that too. There's also a theory that some older people might have developed an immunity as a result of a previous similar virus. The reason it was known as Spanish flu was because Spain had been a neutral country in WW1 and its journalists were free to report the infections, which had been occurring throughout much of Europe. The mobility of troops during the war and the conditions in which they lived probably contributed too. There are people researching Spanish Flu because its DNA still exists in the wild.
I actually disagree that we've been getting the full picture about Covid-19. The Chinese government tried to suppress the initial rumours, but the UK government wasn't much better with all Johnson's stirring "take it on the chin" rhetoric and boasting that he'd shaken hands with sufferers. I'm not the slightest bit surprised he's been infected because he certainly wasn't carrying out social distancing until very recently. We don't actually know his symptoms now. The public is only told what the Number 10 press office chooses to tell us.
Initially, the public was fed the half-baked herd immunity line until there was some kind of damascene conversion and the government realised it had better actually do something.