key: cord-0899982-woiyopyy
authors: Gholami, Mandana; Khamis, Amar Hassan; Ho, Samuel B.
title: Response to “RE: COVID-19 and healthcare workers: A systematic review and meta-analysis.”
date: 2021-03-16
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2021.03.034
sha: ce52c4dc6947c56440ccf6b3930eb648710312c2
doc_id: 899982
cord_uid: woiyopyy

nan

Please cite this article as: Gholami M, Khamis AH, Ho SB, Response to "RE: COVID-19 and healthcare workers: A systematic review and meta-analysis.", International Journal of Infectious Diseases (2021), doi: https://doi.org/10. 1016/j.ijid.2021.03.034 This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. We would like to thank Drs El-Saed and Alshamrani for their helpful questions concerning our paper. The purpose of this paper was to extract data for meta-analysis from all comprehensive studies reporting characteristics and outcomes of healthcare workers (HCW) with PCR-proven Covid-19 infection. We included the N (total population) of HCW in all the tables only if actual data concerning this population was provided in the publication. Our requirement for this data was that it was collected by some form of active survey or testing and not from secondary sources. We did not include data that merely represented an estimate, was a J o u r n a l P r e -p r o o f pg. 2 secondary source, or had unclear methodology. We were consistent throughout the study to use these criteria. We acknowledge that a limitation of this analysis is that some of the included papers lacked accurate data related to this denominator, which can result in overestimation of the result as it relates to an entire population of HCW. Furthermore, we would like to emphasize that the final estimates of percentages and confidence intervals reported in meta-analyses results from estimates of the individual weight of a given study, which is derived from the measures of study size and homogeneity and does not reflect a simple input of the total numbers from all studies into the numerator and the denominator.

In terms of the proportion of HCW that were Covid-19 positive, we reported the overall percentage of Covid-19 positive HCW in all published studies of HCW that met our search criteria, which include some studies that only contained 100% Covid-19 positive HCW in their reports. As mentioned by Drs El-Saed and Alshamrani, the paper of Zheng et al reported comprehensive data related to 2457

Covid-19 positive HCW from Wuhan, China. This paper did mention that in Wuhan there are estimated to be 117,100 HCW, but this data did not meet our inclusion criteria and was not entered (Zheng et al., 2020) . Similarly, we included the data from entire HCW population from which the sample came, we are left with 17 studies with the percentage Covid-19 positive HCW of 12.5% with 95%CI (6.2,23.5). Note that the most accurate or "true" prevalence of Covid-19 among HCW can only come from proper epidemiological studies with rigorous methodologies, or meta-analyses specific to analysing prevalence in entire populations using different criteria and assumptions.

In terms of hospitalization and mortality rates, we used the same criteria for including data related to the N (total population) of HCW within a given study. It is noted that some studies did not include any data at all or any data meeting our criteria for this type of denominator. For example, for Zhan et al we only included the data on 23 deaths that were reported in the publication. It was stated that these occurred from a total estimated population of 3387 HCW with COVID-19 infection in all of China. This was from a secondary source with unclear methodology and was not included (Zhan et al., 2020) . For a sensitivity analysis if we exclude this paper from our analysis the mortality rate is 0.8% with 95%CI (0.4,1.6), which is within the CI of our original estimate. In terms of hospitalization, if we exclude the studies that did not include data for a denominator for the total population (5 studies from China: Chu et al.,2020 Wei et al.,2020 Xing et al.,2020 Zhan et al.,2020 , then the hospitalization estimate is reduced to 4.7% with 95%CI (0.8,10.4). Note the wide CI that overlaps the CI of our original estimate, but these revised data may be more indicative of these rates when considering overall populations.

We do agree with Drs Al Saed and Alshanrani that future reviews and metaanalyses on COVID-19 morbidity and mortality among HCW should differentiate

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