Given 1% IFR for the people from the cruise ship, where everybody was able to be treated properly (or properly enough for this paper's estimate): https://cmmid

Given 1% IFR for the people from the cruise ship, where everybody was able to be treated properly (or properly enough for this paper's estimate): https://cmmid.github.io/topics/covid19/severity/diamond_cruise_cfr_estimates.html https://cmmid.github.io/topics/covid19/severity/diamond_crui... and the current number of deaths in Italy: 1809 one could come to the estimate of actual number of infections in Italy being around 180K people. That big number is real only if Italians managed to treat that many cases as good as it was possible before the hospitals were overwhelmed. What's probably true, however, is that their hospitals already reached their limits and now the number of deaths per infection raises compared to the ideal case, lowering the number of actual infections. But even not using that estimated "bigger number" Italy reports 24747 actually confirmed cases. And assuming that the DNA analysis of this Italian researches is right, Italy's strain must have reached Italy not before January 19th: https://www.reuters.com/article/us-health-coronavirus-italy-scientists/coronavirus-may-have-reached-italy-from-germany-scientists-say-idUSKBN20Y35B https://www.reuters.com/article/us-health-coronavirus-italy-... Even starting from one person at that date we get, for the number of confirmed cases a factor of close to 1.2 per day, or for the assumed cases (a bigger number) 1.24 per day. That gives doubling time between 3 and 4 days, and never longer than that. Note that even a difference of using 24K or 180K infected can't give the factor you suggest: 1.15. That's only observing Italy. I don't know if you are combining Chinese development, where they indeed contained the spread on their territory, with Europe and the rest of the world, where no comparable actions happened (and the actions taken still haven't significantly slowed down the growth), but if you do, that's not proper use of the data available.