Last modified on Mon 14 Dec 2020 16.00 EST The US death toll from Covid-19 crossed the grim milestone of 300,000 Monday, just hours after the first doses of a new vaccine were given to high-risk healthcare workers. Frontline healthcare worker have shouldered an extraordinary burden over the last 10 months and represent a disproportionate share of the sick. The Guardian, in partnership with Kaiser Health News, is investigating the deaths of nearly 1,500 healthcare workers who appeared to have died of Covid-19 after working on the frontlines. The number of dead is expected to climb significantly as new data sources are unlocked in the coming weeks. Our data shows that the majority of healthcare workers who have died are people of color.