Association of University Reopening Policies with New Confirmed COVID-19 Cases in the United States

ImportanceReopening of universities in the U.S. has been controversial in the setting of the coronavirus disease 2019 (COVID-19) pandemic. ObjectiveTo investigate (1) the association between new COVID-19 cases since September 1st with the number of students returning to campus in each county across the U.S. and (2) how different reopening policies at universities correlated with new COVID-19 cases. DesignObservational cohort study using publicly available data sources. Multivariable regression models estimated both effects of university reopening and different reopening policies. Settings and ParticipantsPopulations in U.S. counties reporting new confirmed COVID-19 cases from August 1st to October 22nd. Exposures(1) total enrollment of students under the in-person or hybrid policies per county population and (2) proportion of online and hybrid enrollment within each county. Main Outcomes and MeasuresMean number of daily new confirmed COVID-19 cases per 10,000 county population from September 1st to October 22nd. ResultsFor 2,893 counties included in the study, mean number of daily confirmed cases per 10,000 county population rose from 1.51 from August 1st to August 31st to 1.98 from September 1st to October 22nd. Mean number of students returning to universities was 2.1% (95% CI, 1.8% to 2.3%) of the county population. The number of students returning to campus had an increased association ({beta} = 2.006, P < 0.001) with new confirmed COVID-19 cases within the local county region where the institution resided. For 1,069 U.S. counties with universities, the mean proportion of online enrollment within each county was 40.1% (95% CI, 37.4% to 42.8%), with most students enrolling in-person or hybrid mode. In comparison to holding classes in-person, reopening universities online ({beta} = -0.329, P < 0.001) or in a hybrid mode ({beta} = -0.272, P = 0.012) had a decreased association with new confirmed COVID-19 cases. Conclusions and RelevanceA higher number of students returning to campus in U.S. counties was associated with an increase in new confirmed COVID-19 cases; reopening online or partially online was associated with slower spread of the virus, in comparison to in-person reopening. Key PointsO_ST_ABSQuestionC_ST_ABSAre students returning to universities and specific reopening policies associated with new confirmed coronavirus cases in United States? FindingsIn this cohort study of 2,893 U.S. counties, the number of students returning to campus was significantly associated with a higher number of new confirmed COVID-19 cases. In 1,069 U.S. counties with universities, online or hybrid reopening was significantly associated with a lower risk of new cases compared with in-person reopening. MeaningAn increased risk of coronavirus infection was seen in surrounding regions after universities reopened last fall, and this effect was largest in those holding in-person classes.