american hospitals are in need of help. nearly one in four reporting a critical staffing shortage. thousands of health care workers are out sick with covid-19 as patient numbers rise. >> this has now been the largest influx of patients that we've ever taken care of. >> reporter: in los angeles, so many ambulance crews are out sick some covid patients had to come to the hospital by fire truck. the hypercontagious omicron variant infecting both vaccinated and unvaccinated, but doctors say the vaccines and boosters are highly effective at preventing severe disease. at the doctors community center in maryland, covid cases are up 925% since thanksgiving. about 70% are unvaccinated and the icu is full. nbc's gabe gutierrez visited on friday. >> it's very tough. a lot of times you just have to take a break, you cry and you come back. then you do it all over again. >> reporter: the cdc saying the number of young children hospitalized has also reached alarming levels. >> pediatric hospitalizations