Seroprevalence of SARS-CoV-2 Antibodies and Factors Associated with Seropositivity at the University of Salamanca: The DIANCUSAL Study

[SARS-CoV-2 Exposure and Seroprevalence of SARS-CoV-2 Antibodies among Medical Students in the First Phase of the Pandemic 2020-2021]

BACKGROUND

Due to their clinical training and secondary activities in the hospital, medical students are exposed to contact with SARS-CoV-2 infected people more often than the general population. We determined the seroprevalence of SARS-CoV-2 antibodies in medical students in clinical training at different times during the pandemic and asked participants about possible SARS-CoV-2 exposures in both medical and private settings.

METHODS

From May 2020 to June 2021, medical students each in their 3rd year of training at the University Hospital Würzburg participated in the cross-sectional survey. All SARS-CoV-2 unvaccinated students were offered a determination of their SARS-CoV-2 serostatus. The blood samples were tested by an immunoassay (Elecsys, Roche) for IgG/IgM/IgA antibodies against the SARS-CoV-2 N antigen. Demographic data, SARS-CoV-2 disease and vaccination status, as well as possible SARS-CoV-2 exposures were collected using a questionnaire.

RESULTS

Overall, 383 (86.1%) of 445 students took part in the cross-sectional survey (65% female; median age 22 years; IQR 21-24). Serostatus was determined in 223 (58.2% of 383) SARS-CoV-2 unvaccinated participants. In the period between the beginning of the pandemic in Germany (February 2020) and the time of the survey, 332 (86.7% of 383) students stated that they worked in the medical field, mainly in the context of clinical traineeships (76.8%) or secondary activities with patient contact (48.8%); 129 (33.7%) reported previous contact with a COVID-19 patient, of which 78.3% of contacts took place at a medical facility. Antibodies against SARS-CoV-2 were detected in 8 (3.6%) of the 223 unvaccinated participants tested, and in 3 infected persons an association between infection and contact in the course of medical activity seemed likely.

CONCLUSION

Despite frequent patient contact and the associated increased risk of infection, medical students in their 3rd year of training did not show an increased seroprevalence compared to the general population and showed a lower or similar seroprevalence rate than medical students in other European countries in the first 18 months of the pandemic. This indicates sufficient protection of medical students at the beginning of clinical training through the hygiene and infection protection measures implemented at that time during medical activities.

Predictors of SARS-CoV-2 Infection in University Students: A Case-Control Study

Closure of Higher Education Institutions in the early phase of the SARS-CoV-2 pandemic was largely diffused. With their reopening, numerous preventive measures have been enacted, but limited evidence exists on students' behavior that could influence their infection risk. We conducted a case-control study at the Sapienza University of Rome to identify protective and risk factors for SARS-CoV-2 infection. Students attending the campus within 48 h of SARS-CoV-2 infection were considered cases. Controls were students who come in contact with a confirmed case within the campus. Demographic features and activities carried out before positivity or contact were investigated. Multivariable logistic regression models were built to identify factors associated with SARS-CoV-2 infection, estimating adjusted odds ratios (aOR) and 95% confidence intervals (95% CI). The analysis showed an increased risk of SARS-CoV-2 infection for attending the second year or above of university (aOR 17.7, 95% CI 2.21-142.82) and participating in private parties or ceremonies (aOR 15.9, 95% CI 2.30-109.67) while living outside the family (aOR 0.08, 95% CI 0.01-0.54) and attending practical activities or libraries on campus (aOR 0.29, 95% CI 0.08-0.97) reduced the risk. Data strongly suggests that it may be safe to participate in activities organized under strict infection prevention guidelines. Tailored prevention measures might reduce the risk of infection in university students.