There were people from Italy at that Biogen conference. They might have been asymptomatic, or they might have just decided to glad hand their colleagues while sick, since they flew across the ocean for that opportunitey.
It's worth noting that two days later there was a party in Princeton and two of the Boston conference attendees went there. They were local (Boston) so were presumably just infected at the Boston conference. One of the two (maybe both) managed to infect 12 out of 48 people in a single evening in New Jersey. My take is the upper respiratory infection (not the one the lower that kills people) happens very quickly and is very prone to spread with a sneeze or cough.
That party probably create a good chunk of the initial spread into central Jersey and eastern PA.
Thanks for the additional information surrounding the Biogen conference - I didn’t know all of that.
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MI
Michigan coronavirus cases - 10,791 cases; 417 deaths
https://www.michigan.gov/coronavirus/0,9753,7-406-98163-520743—,00.html
MT
225 Cases
20 Hospitalizations
5 Deaths
https://montana.maps.arcgis.com/apps/MapSeries/index.html?appid=7c34f3412536439491adcc2103421d4b
MO
Cases in Missouri: 1834
Total Deaths: 19
As of 2:00 p.m. CT, April 2
https://health.mo.gov/living/healthcondiseases/communicable/novel-coronavirus/results.php
HI
258 cases; 15 hospitalizations
https://www.civilbeat.org/2020/04/hawaii-reports-34-more-covid-19-cases/
SD
165 cases; 2 deaths
https://www.mitchellrepublic.com/lifestyle/health/5026952-South-Dakota-reports-36-more-positive-COVID-19-cases
AK
Cumulative number of cases hospitalized to date: 09
Cumulative number of deaths to date: 3
Updated April 1, 2020; updates made daily by 5pm and reflect cases reported as of 3pm that day.
http://dhss.alaska.gov/dph/Epi/id/Pages/COVID-19/monitoring.aspx