Threat of COVID-19 in hospital workers lowest for these working in intensive care

A study conducted at a major UK medical center shows that the risk of hospital staff contracting COVID-19 at the height of the coronavirus pandemic is lowest among ICU staff.

The occupational risk of exposure to SARS-CoV-2 has been a matter of great concern since the SARS-CoV-2 pandemic began. Because of the nature of their work, healthcare doctors are at risk of infection from SARS-CoV-2, and studies have shown that infection rates are higher among healthcare workers than the general population. Infection rates of up to 14% in symptomatic and 7.1% in asymptomatic hospital staff indicate that they are at an increased occupational risk for COVID-19.

One of the largest hospital trusts in the UK – the NHS Foundation Trust (UHBFT) at University Hospitals Birmingham has decided to conduct a cross-sectional study of 554 employees within the trust. The aim was to determine the point prevalence of the infection and the seroprevalence of SARS-CoV-2 antibodies in healthcare workers. It also looked at the study participant's relationship to previous symptoms of COVID-19 and the hospital departments where they worked. By trying to understand the relationship between infection, symptoms, and subsequent serological responses, researchers gain vital information to understand herd immunity, vaccine development, and workforce protection.

The study recruited 545 asymptomatic healthcare workers who were invited to participate through UHBFT's social media. The exclusion criteria included current symptoms consistent with COVID-19. A nasopharyngeal swab and a venous blood sample were tested for SARS-CoV-2 RNA and anti-SARS-CoV-2 spike glycoprotein antibodies, respectively, from each participant.

The results, published in the journal Thorax, showed that doctors' risk of COVID-19 infection was lowest among ICU staff at the height of the pandemic. The highest risk of infection was found by cleaning staff, acute and general practitioners, and people with black, Asian and ethnic backgrounds (BAME).

Almost 2.5% of health workers who showed no symptoms tested positive for SARS-CoV-2, and 38% developed COVID-19 symptoms. 26% said they had previously had symptoms related to COVID-19 infection, and patients with previous symptoms were found to be significantly more likely to develop antibodies than those without symptoms. The overall seroprevalence (prevalence of antibody positivity) was 24%, compared to 6% in general in the Midlands region at the time.

The researchers discuss that fewer intensive care clinics received SARS-CoV-2 because they were using improved personal protective equipment (PPE) that included a mandatory respirator with a filtered face piece (Class 3). Fluid-resistant surgical masks have been used in other clinical areas. The use of improved PPE to protect staff from SARS-CoV-2 infection should be further explored. These studies must also examine the availability of training, space and supervision to use PPE appropriately and effectively.

The data gathered from this study will be useful for future planning on how best to protect health workers in the event of a further surge in cases or future pandemics. Lessons can also be learned and applied to the impact of influenza on the health care system and health care workers each winter.

Written by Helen Massy, ​​BSc

References:

EurekAlert !. 2020. Hospital COVID-19 risk lowest among ICU staff. (online) Available at: (Accessed September 16, 2020).

Shields, A., Faustini, S., Perez-Toledo, M., Jossi, S., Aldera, E., Allen, J., Al-Taei, S., Backhouse, C., Bosworth, A., Dunbar L., Ebanks, D., Emmanuel, B., Garvey, M., Gray, J., Kidd, I., McGinnell, G., McLoughlin, D., Morley, G., O'Neill, J. ., Papakonstantinou, D., Pickles, O., Poxon, C., Richter, M., Walker, E., Wanigasooriya, K., Watanabe, Y., Whalley, C., Zielinska, A., Crispin, M ., Wraith, D., Beggs, A., Cunningham, A., Drayson, M., and Richter, A., 2020. SARS-CoV-2 seroprevalence and asymptomatic virus transport in healthcare workers: a cross-sectional study. Thorax, S. Thoraxjnl-2020-215414.

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