SARS-COV-2 seroprevalence among all healthcare workers in a tertiary hospital in Spain.

BACKGROUND: Healthcare workers (HCWs) have been a critical and vulnerable population during SARS-CoV-2 pandemic. The aim of this study was to determine the overall seroprevalence and to evaluate occupational risk factors among HCWs in one of the countries most affected by this pandemic. METHODS: We conducted a seroprevalence study for SARS-CoV-2 in a tertiary hospital in Madrid (Spain) between 24 April and 8 May 2020. A total of 4894 HCWs were invited for serologic testing. Serum samples were tested for SARS-CoV-2 IgM and IgG antibodies using Enzyme Immunoassay (ELISA) and Electro-Chemiluminescence Immunoassay (ECLIA) techniques. We calculated odds ratios to assess association between demographic and occupational characteristics with SARS-CoV-2 seroconversion. RESULTS: We processed 4324 serum samples. Overall, seroprevalence was of 16.6% (95% CI: 15.5-17.7). We found statistically significant differences in SARS-CoV-2 seroprevalence by type of employee, professional category, department and type of activity performed during the pandemic period, while no differences were identified between the personnel working in the COVID-19 wards compared to those working in non-COVID-19 wards. We confirmed 268 (26.7%) infections among 1005 hospital staff members tested by PCR. 60.5% of HCWs infected by SARS-CoV-2, assessed either by PCR or serology, could be considered asymptomatic or paucisymptomatic. CONCLUSIONS: HCWs have an increased risk of SARS-CoV-2 infection but COVID-19 patient exposure was not a determining factor. Universal mask wearing should be mandatory in healthcare settings given the important number of asymptomatic and paucisymptomatic cases.

Negative Transmission of SARS-CoV-2 to Hand-Expressed Colostrum from SARS-CoV-2-Positive Mothers.

Aim: The objective of our study was to determine whether the SARS-CoV-2-positive mothers transmit the virus to their hand-expressed colostrum. Methods: This is an observational prospective study that included pregnant women who tested positive for SARS-CoV-2 by PCR test on a nasopharyngeal swab at the moment of childbirth and who wanted to breastfeed their newborns. A colostrum sample was obtained from the mothers by manual self-extraction. To collect the samples, the mothers wore surgical masks, washed their hands with an 85% alcohol-based gel, and washed their breast with gauze that was saturated with soap and water. Results: We obtained seven colostrum samples from different mothers in the first hours postdelivery. SARS-CoV-2 was not detected in any of the colostrum samples obtained in our study. Conclusion: In our study, breast milk was not a source of SARS-CoV-2 transmission. Hand expression (assuring that a mask is used and that appropriate hygienic measures are used for the hands and the breast), when direct breastfeeding is not possible, appears to be a safe way of feeding newborns of mothers with COVID-19.