Researchers hope this old-fashioned treatment will work for coronavirus

Phlebotomist Jenee Wilson carries COVID-19 convalescent plasma from a donor at Bloodworks Northwest on April 17, 2020 in Seattle, Washington. (Photo by Karen Ducey/Getty Images)

(CNN)Plasma Technologies LLC has signed a defense contract worth $750,000 to develop scaled-up Covid-19 convalescent plasma technologies, according to an announcement on the Department of Defense website Monday.

It's the latest development in the effort to use a 19th century treatment to help 21st century patients.