The objective of the study is to determine the percentage of past SARS-CoV-2 infections in hospital health personnel involved in the care of people with COVID-19 in HUGTiP and in Badalona Serveis Assistencials de Badalona.

Health personnel, especially hospital workers, have been a group especially affected by the COVID-19 epidemic. According to data from the Ministry of Health, in Spain 26% of health personnel have been infected by COVID-19, for a total of 31,053 professionals, representing up to 18.5% of all infections in the Spanish state, with variations between the different autonomous communities.1 In Italy it was estimated that up to 20% of health workers who responded to the epidemic would have been infected within a month.

There are no unified guidelines at the state level to determine infection prevention strategies in health personnel in order to validate them, beyond the use of Personal Protective Equipment (PPE) in personnel and general strategies for isolation and prevention of transmission.

There are no approved drug prevention strategies for primary prophylaxis against COVID-19.

Currently, there are no universal mass screening strategies (virological or immunological) to estimate the actual number of health personnel with an asymptomatic infection, as well as to determine the percentage of personnel who have already passed the infection asymptomatically or to determine the percentage of personnel A healthcare provider who has developed some form of immunity following a confirmed COVID-19 infection.

The HUGTiP, like the rest of Catalan hospitals, has suffered a massive avalanche accumulated in the time of admission by COVID-19, which has forced it to adopt different innovative strategies to visit them in emergencies, enter them in conventional hospitalization in a conventional plant, or attend them in the intensive care units that had to be created de novo against the clock. As of April 20, 2020, 1,000 hospital discharges have been granted to patients admitted by COVID-19 in conventional hospitalization plants and 170 more discharges from those admitted to intensive care units at HUGTiP. Likewise, the Municipal Hospital of Badalona has given a total of 300 discharges of patients with COVID-19, and they have also reported about 180 infections in their health personnel in this period.

Due to the high transmission rate of SARS-CoV-2 and its potential severity, several healthcare workers at HUGTiP decided on their own to take empirical primary prophylaxis with oral hydroxychloroquine individually as prevention of SARS-CoV-2 infection.

Inclusion Criteria:

• Adults (age> 18 years) who have worked during the epidemic period (March and April 2020) in the Infectious Diseases, Pneumology, Emergencies, ICU and Internal Medicine departments of HUGTiP, or in the Internal Medicine or Emergency departments of the Badalona Municipal Hospital.

Exclusion Criteria:

• Participation will be voluntary and no exclusion criteria are established

- Adults (age> 18 years) who have worked during the epidemic period (March and April 2020) in the Infectious Diseases, Pneumology, Emergencies, ICU and Internal Medicine departments of HUGTiP, or in the Internal Medicine or Emergency departments of the Badalona Municipal Hospital.