BACKGROUND AND GOALS: The aim of the study is to know the prevalence of SARS-CoV-2 infection in patients and professional staff of a medium or long-stay hospital during the peak period of the pandemic in Spain, spring 2020 . MATERIAL AND
METHODS: At the end of February 2020, we developed at the hospital a strategy to diagnose the SARS-CoV-2 infection consisting of complementing the realization of PCR tests at real time with a quick technique of lateral flow immunochromatography to detect IgG and IgM antibodies against the virus . We also developed a protocol to realize those diagnostic tests and considered an infection (current or past) a positive result in any of the above tests . We included 524 participants in the study (230 patients and 294 hospital staff), and divided them into hospital patients and Hemodialysis outpatients . Furthermore, we divided the hospital staff into healthcare and non-healthcare staff . The documented period was from March , 20th to April , 21st , 2020 .
RESULTS : 26 out of 230 patients tested positive in any of the diagnostic techniques (PCR, antibodies IgG, IgM) with a 11.30% prevalence . According to patients groups, we got a 14.38% prevalence in hospital patients vs. 5.95% in outpatients, with a significantly higher risk in admitted patients after adjustment for age and gender (OR=3,309 , 95% CI : 1,154-9,495). 24 out of 294 hospital staff tested positive in any of the diagnostic techniques, with a 8.16% prevalence . According to the groups, we got a 8.91% prevalence in healthcare staff vs. 4.26% in non-healthcare staff . Thus, we do not see any statistically significant differences between hospital staff and patients as far as prevalence is concerned (P=0,391), (OR=2,200 , 95% CI : 0,500-9,689).
CONCLUSIONS: The result of the study was a quite low prevalence rate of SARS-CoV-2 infection, in both patients and hospital staff, being the hospital patients' prevalence rate higher than the outpatients', and the healthcare staff higher than the non-healthcare's . Combining PCR tests (gold standard) with antibodies tests proved useful as a diagnostic strategy.