First the Fearmonger's Spin

"Chelsea had 315 COVID-19 cases on April 7 which, with a population of 40,000, means they are seeing roughly 79 cases per 10,000 residents — four times the rate of surrounding neighborhoods.

Officials on Thursday said that number has grown to 387 confirmed cases, which translates to 96 cases per 10,000 residents. Thirty-eight Chelsea residents have recovered from the virus and 10 have died, officials said."

The Translation

387 cases per 40,000 is 0.9% of the population was found to be infected with Covid-19*
10 deaths per 40,000 is 0.025% death rate from Covid-19, similar to normal influenza.

*Since then, a new study is showing closer to 1/3 of the population of Chelsea, Mass has Covid-19 antibodies.

The newer study claims 39 deaths of the 40,000 population, which bumps the 0.025% death rate number from above up to a 0.0975% death rate, still about the same as normal influenza. See 2nd, 3rd, and 4th [randomly picked] sources below.

The Sources

https://www.masslive.com/coronavirus/2020/04/coronavirus-in-massachusetts-chelsea-now-a-covid-19-hotspot-city-officials-plead-for-assistance.html

https://orionscoldfire.com/index.php/2020/04/18/33-of-those-tested-in-chelsea-ma-had-covid-19-antibodies-in-their-blood/

https://www.nydailynews.com/coronavirus/ny-coronavirus-chelsea-massachusetts-20200419-qsz2kztiancxddakbgvd76jura-story.html

https://www.redstate.com/alexparker/2020/04/18/massachusetts-general-hospital-chelsea-study-antibodies-test-coronavirus-john-lafrate-bellingham-square/

https://www.thestuffnews.com/2020/04/18/one-third-massachusetts-antibody-test/