key: cord-0917710-84w7x96g
authors: Rodríguez-Domínguez, M.; Romero-Hernández, B.; Marcos-Mencía, D.; Fernandez-Escribano, M.; Ferré-Masferrer, M.; Galán, J.C.; Cantón, R.
title: SARS-CoV-2 Antibodies and utility of point of care testing in Health Care Workers from a Spanish University Hospital in Madrid
date: 2021-04-01
journal: Clin Microbiol Infect
DOI: 10.1016/j.cmi.2021.03.018
sha: 66f6daf052d037b95ceb000c77925072db76077a
doc_id: 917710
cord_uid: 84w7x96g

nan

To the Editor: Spain is one of the most affected countries by the SARS-CoV-2 pandemic. There were nearly two million confirmed cases and more than 50,000 deaths by December 2020 (1). A recent national serological surveillance study carried out in our country detected an overall 5% seroprevalence in the general population, with important geographical variability that ranged from 3% to 10% (2).

Health care workers (HCW) have an increased risk of exposure to SARS-CoV-2.

Household contacts and the socialization between HCW could also have expose to infection.

Our objective was to analyze the impact of the first peak of the COVID-19 pandemic in HCW from a tertiary teaching Hospital of Madrid (Spain), as well as evaluate of a lateral flow inmunoassay (LFIA) for applicability to seroprevalence studies. The study was carried out in May-June 2020, during the slowdown phase of the epidemic wave.

To avoid selection bias, serology testing was offered to all staff working in the Hospital Massachusetts, USA). In this group a second serum sample was obtained two weeks after the first one for IgG seroconversion analysis. Prevalence among non-sanitary professionals was 16.8% (CI 13.7%-20.7%). First-line specialities as pneumology, internal medicine, geriatrics, emergencies or infectious diseases showed a prevalence of nearly 30%, but also second line specialties as traumatology (36.5%), psychiatry (31.5%) or rheumatology (31.4%). On the other hand, prevalence was significantly lower (13.7-17.5 % respectively) in highly-exposed staff from anesthesiology and intensive care units, which could be related to a higher perception of the risk and to extreme preemptive measures in the daily work.

Interestingly, 11.5% of IgG positive HCW did not have any history of PCR testing which could correspond to undiagnosed infections. Conversely, IgG was not detected in 6.1% Our results contrast with lower prevalences in HCW from other countries. Local variations in Hospital settings had been reported but always in agreement with J o u r n a l P r e -p r o o f community incidence, also in contrasts to our findings (4) . Community acquisition as well as transmission between staff members cannot be ruled out as shown by the high prevalence found in non-health professionals (20.7%). The higher prevalence found in men than women is also relevant, particularly considering that two thirds of the HCWs of our institution are women. This difference in sex prevalence was not found in the national serosurvey (2). We detect 1.1% of asymptomatic infections which is relevant considering that the study was carried out when the positivity rate in our hospital was under 1% and infections in the community were in the base of the epidemic curve.

Seroprevalence studies are crucial for assessing the impact of the pandemic and for evaluating control measures. The use of a rapid test, as LFIA, could be a suitable tool for this purpose. Our results demonstrate a good agreement between LFIA and the reference technique for IgG detection.

In conclusion, infections in HCW could increase the worsening of the pandemic by collapsing health services. HCW could contribute as a source of transmission to other coworkers, patients and their own relatives and households.

We want to thank Laura del Campo Albendea for help with statistical analysis, Laura Martinez-García, Melanie Abreu and Magdalena Muedra for helping in carry-out the study and data collection. Also to Mary Harper for English revision of the manuscript We are deeply grateful to all laboratory technicians, administrative personnel and nurses who made this seroprevalence study possible.

There are no conflict of interest

The study was performed with the own hospital resources. 

Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study Lancet

Substantial undocumented infection facilitates the rapid dissemination of novel coronavirus (SARS-CoV-2)

Seroprevalence of SARS-CoV-2 among frontline health care personnel in a multistate hospital network -13 academic medical centers