Frequency of SARS-CoV-2 Infections among Healthcare Workers in Germany: 3-Year Follow-Up Study

TL;DR

This study found that healthcare workers in Germany who had frequent contact with COVID-19 patients did not have higher infection rates compared to those with less or no patient contact.

Contribution

The study provides a 3-year follow-up on SARS-CoV-2 infection rates among healthcare workers and evaluates immune responses across different risk groups.

Findings

Healthcare workers with high patient contact did not have higher infection rates than those with low or no patient contact.

Vaccination and hygiene measures effectively limited virus transmission to healthcare workers.

Immune responses were similar across all groups, regardless of patient contact level.

Abstract

The emergence of SARS-CoV-2 in 2019 led to a global pandemic with a significant impact on healthcare systems. Healthcare workers were particularly vulnerable due to frequent contact with COVID-19 patients. Despite vaccination, they remained at higher risk as the vaccines provided limited protection against infection with viral variants, like Delta or Omicron BA.1 and BA.5. Three years after the onset of the pandemic, we evaluated SARS-CoV-2 infection frequencies among healthcare workers with varying levels of patient contact: high-risk (frequent COVID-19 patient contact), intermediate-risk (non-COVID-19 patient contact), and low-risk (no patient contact). We assessed their cellular and humoral immune responses based on their vaccination status and number of prior infections. SARS-CoV-2-specific antibodies were measured by immunoglobulin ELISA, and neutralizing antibody titers were determined against the viral variants D614G, Delta, and Omicron BA.1 and BA.5. Cellular immune responses were analyzed using an interferon-γ ELISpot. Notably, three years into the pandemic, healthcare workers in daily contact with COVID-19 patients did not have higher infection rates compared to healthcare workers with non-COVID-19 patient contact or no patient contact. Immune responses were similar across all groups, highlighting the effectiveness of vaccination and current hygiene standards in preventing virus transmission from patients to staff.

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