As coronavirus vaccination numbers increase, hospitals begin slow return to normal Doctors say new data from Vanderbilt University Medical Center shows how effective the COVID-19 vaccine has been in real-world situations. and last updated 2021-04-27 07:54:09-04 NASHVILLE, Tenn. (WTVF) â Doctors say new data from Vanderbilt University Medical Center shows how effective the COVID-19 vaccine has been in real-world situations. The study looked at coronavirus patients at VUMC hospitals from December to early April. According to the data,1,833 patients were admitted with a positive COVID-19 test. Of those patients, 1,793 were not vaccinated, 29 had received only the first dose, and seven had gotten a second dose of vaccine, but it was within two weeks of their second shot. Only four of the patients were fully vaccinated for COVID-19.