. >> don mcneil, what do you make of this? >> i'm glad dr.king a bit. i found that piece that he wrote in the times shocking from somebody who has an m.d. and some of the interviews he gave afterwards, because it essentially argued that we should trade lives for his father's 401(k), that we should let people out there so that we can achieve herd immunity. the whole concept of herd immunity is different when you have a novel virus. herd immunity in the old days was something the old had because they survived smallpox and they were able to keep the economy going and till the fields while the young recuperated. the ones who survived. right now we're in a situation where nobody has herd immunity. saying we all can go back to work on easter or a couple months from easter is asking to watch enormous numbers of people die. the original paper said we should just put away the vulnerable, make sure they're okay. perhaps dr. katz's parents have a nice house. he's a retired cardiologist. but many elderly people -- i checked the stats, there's 50 million

. >> reporter: christine mcneil donning her protective gear raleigh-durham to go out -- ready to go out and test residents in her community who fear they have the disease. christine became a teacher. now heading back to the front lines. >> i assume everybody is positive. i do a lot of testing in the garage, out on the back porch i only go into the home if i have to. >> reporter: she belongs to the medical reserve corps, volunteers nationwide stepping forward >> i don't want somebody to be there needing help, and there isn't anybody to help them. >> reporter: this woman, who hadn't treated patients in four years calling the er where she used to work offering nursing help. >> i didn't want to be one of those people who didn't do anything. >> reporter: medical heroes responding to the warlike plea from new york, california, and virginia we need you and we need you right away. >> reporter: in new york city, officials say as many as 1,000 people responded within the first 24 hours w. the illness spreading quickly and the medical staffs possibly overwhelmed, this city and others still are ask