Asymptomatic SARS-CoV-2 infection among healthcare workers in a non-COVID-19 teaching university hospital


Background: During the COVID-19 pandemic, most of the published reports on COVID-19 emphasized that health care workers (HCWs) get infected more than the general population representing one of the most vulnerable groups. However, that the real percentage of HCWs infected by SARS-CoV-2 in Egypt remains unknown. The researchers conducted the current study to assess seroprevalence of SARS-CoV-2 IgG among HCWs working in a hospital with no SARS-CoV-2 patients, and to identify the potential factors associated with SARS-CoV-2 IgG seropositivity.
Design and Methods: The current study is a cross-sectional study carried out among 455 HCWs at Cairo University Hospital. The researchers administered a questionnaire shortly before the SARS-CoV-2 rapid test is performed using closed-ended question format to obtain information on demographic data of the study participants including age, sex, specialty, clinical information including questions about medical conditions, and. history of previous exposure with a confirmed or suspected case of COVID-19, and history of COVID-19- compatible symptoms during the previous 14 days (cough, sore throat, runny nose, fatigue, shortness of breath, fever, headache, vomiting, diarrhea, anosmia, ageusia, and chills).
Results: We screened 455 HCWs for SARS-CoV-2 antibodies, 31.4% were in the high-risk group, and 68.6% in the low-risk group. The overall IgG seroprevalence was 36 (7.9%) (95% CI 5.8 to 10.8). The IgG seroprevalence was significantly higher in low-risk group 11% (35/312) versus high-risk group 0.7% (1/143), p<0.001.
Conclusions: Low seropositivity rates for SARS-CoV-2 among HCWs is suggestive of lack of immunity and we are still far from herd immunity.



PlumX Metrics


Download data is not yet available.


Wang D, Hu B, Hu C, et al. Clinical characteristics of 138 hospitalized patients with 2019 novel coronavirus-infected pneumonia in Wuhan, China. JAMA 2020;323:1061–9. DOI:

Mahase E. Coronavirus COVID-19 has killed more people than SARS and MERS combined, despite lower case fatality rate. BMJ 2020;368:m641. DOI:

Keeling MJ, Hollingsworth TD, Read JM. Efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19) J Epidemiol Community Health 2020;74:861-6. DOI:

Zou L, Ruan F, Huang M, et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. N Engl J Med 2020;382:1177-9. DOI:

Rivett L, Sridhar S, Sparkes D, et al. Screening of healthcare workers for SARS-CoV-2 highlights the role of asymptomatic carriage in COVID-19 transmission. Elife 2020;9:e58728.

Olmos C, Campaña G, Monreal V, et al. SARS-CoV-2 infection in asymptomatic healthcare workers at a clinic in Chile. PLoS One 2021;16:e0245913. DOI:

Occupational Safety and Health Administration, United States Department of Health. COVID-19 and the workplace. Accessed: 2021 Mar 3. Available from:

World Health Organization. Health workers exposure risk assessment and management in the context of COVID-19 virus: interim guidance, 4 March 2020. World Health Organization. Available from:

Liu M, Cheng SZ, Xu KW, et al. Use of personal protective equipment against coronavirus disease 2019 by healthcare professionals in Wuhan, China: cross sectional study. BMJ 2020;369:m2195. DOI:

Paderno A, Fior M, Berretti G, et al. SARS-CoV-2 infection in healthcare workers: cross-sectional analysis of an otolaryngology unit. Otolaryngol Head Neck Surg 2020;163:671-2. DOI:

Pollán M, Pérez-Gómez B, Pastor-Barriuso R,et al. Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study. Lancet 2020;396:535-44. DOI:

Stringhini S, Wisniak A, Piumatti G, et al. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV-POP): a population-based study. Lancet 2020;396:313-9. DOI:

Korth J, Wilde B, Dolff S, Anastasiou, et al. SARS-CoV-2-specific antibody detection in healthcare workers in Germany with direct contact to COVID-19 patients. J Clin Virol 2020;128:104437. DOI:

Galan I, Velasco M, Casas ML, et al. SARS-CoV-2 seroprevalence among all workers in a teaching hospital in Spain: Unmasking the 267 risk. medRxiv 2020.05.29.20116731.

Abdelmoniem R, Fouad R, Shawky S, et al. SARS-CoV-2 infection among asymptomatic healthcare workers of the emergency department in a tertiary care facility. J Clin Virol 2021;134:104710. DOI:

Original Articles
COVID-19, seroprevalence, IgG, asymptomatic, health care workers
  • Abstract views: 775

  • PDF: 349
  • HTML: 0
How to Cite
Mukhtar, A., Afishawy, M., Alkhatib, E., Hosny, M., Ollaek , M., Elsayed, A., Salem, M. R., & Ghaith, D. (2021). Asymptomatic SARS-CoV-2 infection among healthcare workers in a non-COVID-19 teaching university hospital . Journal of Public Health Research, 10(3).