Overview
The primary objective of this study is to establish differences in susceptibility to SARS CoV-2 infection among health care workers (HCW) highly exposed to patients with COVID-19 diagnosis. To ascertain this issue, we evaluated:
- Changes in receptor polymorphism (ACE2 and CD26 receptor study.
- SARS-CoV-2 CD4/CD8 T cell response (CTL)
- Different KIR phenotypes
Description
Only 24% of health care workers (HCW) had developed inmunological response to SARS CoV-2 infection in one centre attending thousands of COVID-19 patients, and with shorteness of personal protective equipments. Our hypothesis is that this relatively low number of infected HCW could be secondary to:
- Differences in susceptibility to infection mediated by changes in viral receptors. Thus, it is important to characterize and genotyping the main receptor for SARS-CoV-2, ACE2, and other related receptor, such as CD26.
- Increased cellular immune response, offering cross-immunity against SARS CoV-2 infection by previous exposure to other coronavirus or respiratory pathogens. A specific CD4/CD8 T cell response to viral peptides could respond this question
- Specific KIR phenotypes (Killer Immunoglobulin-like Receptors): Natural killer cells (NK) response to alterations of class I HLA molecules presented in infected cells. An increase in class I HLA expression could lead to an increase in NK activation by increasing its ability to produce IFN-gamma.
Eligibility
Inclusion criteria
- HCW older than 18 years
- Highly exposed to COVID-19 according to the definition
- Negative (cases) or positive (controls) serology against SARS-CoV-2 infection Exclusion criteria
- Presence of any disease / treatment which could alter the susceptibility (corticoid therapy, chemotherapy, monoclonal antibodies)
- Pregnancy
High exposure definition: direct and continued care of COVID-19 diagnosed patients for 2 weeks or more, without aerosol- generating procedures, with inappropriate personal protective equipment (PPE), or unprotected exposure to patients with COVID-19 during aerosol-generating procedures.
The definition of appropriate PPE was based on previous recommendations. The absence of any part of the PPE constituted an unprotected exposure. We defined the following as aerosol-generating procedures: airway suction, application of a high-flow O2 instrument, bronchoscopy, endotracheal intubation, tracheostomy, nebulizer treatment, sputum induction, positive pressure ventilation, manual ventilation and cardiopulmonary resuscitation.