Low SARS-CoV-2 seroprevalence but high perception of risk among healthcare workers at children’s hospital before second pandemic wave in Germany

Background Healthcare workers are considered a particularly high-risk group during the coronavirus disease 2019(COVID-19)pandemic.Healthcare workers in paediatries are a unique subgroup:they come into frequent contact with children,who often experience few or no symptoms when infected with severe acute respiratory syndrome coronavirus 2(SARS CoV-2)and,therefore,may transmit the disease to unprotected staff.In Germany,no studies exist evaluating the risk of COVID-19 to healthcare workers in paediatric institutions.Methods We tested the staff at a large children's hospital in Germany for immunoglobulin(Ig)G antibodies against the nucle-ocapsid protein of SARS CoV-2 in a period between the first and second epidemic wave in Germany.We used a questionnaire to assess each individual's exposure risk and his/her own perception of having already been infected with SARS-CoV-2.Results We recruited 619 participants from all sectors,clinical and non-clinical,constituting 70%of the entire staff.The seroprevalence of SARS CoV-2 antibodies was 0.325%(95%confidence interval 0.039-I.168).Self-perceived risk of a previ-ous SARS-CoV-2 infection decreased with age(odds ratio,0.81;95%confidence interval,0.70-0.93).Having experienced symptoms more than doubled the odds of a high self-perceived risk(odds ratio,2.18;95%confidence interval,1.59--3.00).There was no significant difference in self perceived risk between men and women.Conclusions Seroprevalence was low among healtheare workers at a large children's hospital in Germany before the second epidemic wave,and it was far from a level that confers herd immunity.Self-perceived risk of infection is often overestimated.