Keeping university open did not increase the risk of SARS-CoV-2 acquisition: a test negative case-control study among students

Background: During the SARS-CoV-2 testing program offered through the RT-PCR test by Sapienza University of Rome, we conducted a test-negative case-control study to identify risk factors for acquiring SARS-CoV-2 infection among university students. Methods: Each SARS-CoV-2-positive case detected was matched to two controls randomly selected from students who tested negative on the same day. 122 positive students and 244 negative students were enrolled in the study. Multivariable conditional logistic regression models were built. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were calculated. A second model was limited to students who had attended campus. Results: Out of 8223 tests for SARS-CoV-2, 173 students tested positive (2.1%), of whom 122 (71.5%) were included in the case-control study. In the first analysis, being a non-Italian student (aOR: 8.93, 95% CI: 2.71-29.41), having received only the primary vaccination course (aOR: 2.94, 95% CI: 1.24-6.96) compared to the booster dose, known exposure to a COVID-19 case or someone with signs/symptoms suggestive of COVID-19 (aOR: 6.51, 95% CI: 3.48-12.18), and visiting discos (aOR: 4.07, 95% CI: 1.52-10.90) in the two weeks before testing increased the likelihood of SARS-CoV-2 infection. Conversely, students attending in-person lectures on campus seemed less likely to become infected (aOR: 0.34, 95% CI: 0.15-0.77). No association was found with other variables. The results of the second model were comparable to the first analysis. Conclusions: This study indicates that if universities adopt strict prevention measures, it is safe for students to attend, even in the case of an infectious disease epidemic.