Objectives Quantify the effects of characteristics of nursing homes and their surroundings on the spread of COVID-19 outbreaks and assess the changes in resident protection between the first 2 waves (March 1 to July 31 and August 1 to December 31, 2020). Design An observational study was carried out on data on COVID-19 outbreaks extracted from a database that monitored the spread of the virus in nursing homes. Setting and Participants The study concerned all 937 nursing homes with >10 beds in Auvergne-Rhône-Alpes region, France. Methods The rate of nursing homes with at least 1 outbreak and the cumulative number of deaths were modeled for each wave. Results During the second (vs the first wave), the proportion of nursing homes that reported at least 1 outbreak was higher (70% vs 56%) and the cumulative number of deaths more than twofold (3348 vs 1590). The outbreak rate was significantly lower in public hospital–associated nursing homes than in private for-profit ones. During the second wave, it was lower in public and private not-for-profit nursing homes than in private for-profit ones. During the first wave, the probability of outbreak and the mean number of deaths increased with the number of beds (P < .001). During the second wave, the probability of outbreak remained stable in >80-bed institutions and, under proportionality assumption, the mean number of deaths was less than expected in >100-bed institutions. The outbreak rate and the cumulative number of deaths increased significantly with the increase in the incidence of hospitalization for COVID-19 in the surrounding populations. Conclusions and Implications The outbreak in the nursing homes was stronger during the second than the first wave despite better preparedness and higher availabilities of tests and protective equipment. Solutions for insufficient staffing, inadequate rooming, and suboptimal functioning should be found before future epidemics.