On: In Italian town of 3k, 50-75% of Covid-19 cases are asymptomatic but contagious

But what percentage are pre-symptomatic? If cases are doubling every 5 days, and it takes 5 days for symptoms to show, might that explain result?

However the Italian study appears to agree with this preprint about another complete population study: https://www.medrxiv.org/content/10.1101/2020.03.05.20031773v...

That paper shows that the effect is age related: People over ~50 have a ~50% chance of being asymptomatic, under 50 years is ~10% asymptomatic.