COVID-19 Infection Across Workplace Settings in Qatar, a Comparison of COVID-19 Positivity Rates of Screened Workers From March 1st Until July 28th, 2020

Abstract


Introduction
The current COVID-19 outbreak that emerged in Wuhan City, Hubei Province, China [i] , represents one of the most challenging public health threats faced globally.On January 30, 2020, the World Health Organization (WHO) declared COVID-19 a public health emergency of international concern [ii] .By the second week of July 2020, there had been more than 13 million con rmed cases across 215 countries [iii] .
The initial stage of the epidemic in the State of Qatar started on February 29 th , 2020, with a COVID-19 positive case of a Qatari citizen traveling back from Iran, who was isolated upon his arrival, followed by additional citizens traveling back to the State of Qatar, who were also put into isolation to avoid community spread.On March 11 th , the State of Qatar witnessed a sudden surge of 226 locally transmitted new cases in one day, which entailed an outbreak through localized transmission, wherein sporadic infections with the pathogen occurred.On May 22 nd , the Ministry of Public Health declared that the State of Qatar had entered the peak phase of the pandemic represented by widespread human infection in the country.By the second week of July, Qatar had recorded more than 109,000 con rmed COVID-19 cases, relative to a total of 2.7 million inhabitants [iv] .
A major route of COVID-19 transmission has already been identi ed as the workplace setting [v] .The association between workplace site exposure and the disease is signi cant: the rst documented case was amongst persons working in a seafood wholesale market in Wuhan [vi] .Additionally, it has been o cially declared as an occupational disease in countries like South Africa and Canada when it is considered the result of occupational exposure.Germany and Italy have also identi ed COVID-19 as an occupational disease but only limited to the healthcare sector [vii] .
Moreover, several research papers have been published, illustrating the prevalence of exposed workers in the healthcare Industry [viii] , [ix]   .According to preliminary data from China, healthcare workers (HCWs) facing COVID-19 represent a high-risk category , [xi]   .Although healthcare workers are exposed to a particular risk of infection because of the nature of their work, workers in other workplace settings could also have increased risk for COVID-19 infection because of the environment they work in and continuity of their work during the pandemic; this includes front line workplace settings, food-related workplace settings and work that requires proximity based interactions.The US Occupational Information Network (O*NET) has developed a COVID-19 Occupational Risk Score to determine which occupations face the highest risk of exposure to COVID-19 based on three criteria: contact with others, physical proximity, and exposure level.
The O*NET risk scores place healthcare workers, paramedics, and ight attendants in the high-risk categories [xii] .
In Qatar, the government has strategized and implemented restrictions due to the pandemic to allow partial functioning of all workplaces.However, many workplace settings remained fully operational, which highlights the importance of understanding the burden of COVID-19 at the workplace as well as its parameters.This study will estimate the risk of exposure of screened workers at various workplace settings in the State of Qatar by analyzing and comparing the respective positivity rates.

Methodology
A cross-sectional study was conducted utilizing surveillance data available from various sources.All workplaces with ten or more laboratory-con rmed cases of COVID-19 during the period of March 1 st to July 28 th , 2020, were included for analysis.Any con rmed cases not working in the identi ed companies, people below 18 years of age, students, and retired people, were excluded from the study.
A list of 1,800 workplaces with at least 10 con rmed COVID-19 cases, as of July 28 th , 2020, was generated from the surveillance database for COVID-19 case investigations.The surveillance database aggregates patient laboratory data and the corresponding patients' employment data to identify workplace clusters.
The researchers have categorized these workplaces using a mapping table adapted from the North American Industry Classi cation System (NAICS) codes 2017 version [i] .The NAICS classi es businesses and industries into different levels of aggregation based on the economic sectors.In this study, the researchers used the broader NAIC categories (20 codes) and adapted them to Qatar's economic and social contexts (11 codes): 1.The Oil & Gas sector that includes companies specialized in energy upstream, midstream, and downstream.
2. The construction and related workplace setting that comprises the construction and contracting companies as well as manufacturers specialized in construction equipment and material.
3. The Retail and Wholesale trades setting that includes grocery stores, pharmacies as well as factories, manufacturers, and agriculture domain.
4. The Finance & Business workplace setting that consists of banks and nancial institutions as well as private businesses offering consulting services or administrative support.
5. The Transportation and Warehousing workplace setting that includes transportation services and facilities and entities specialized in warehousing and storage.
. The Support, Waste Management, and Remediation Services workplace setting that comprises cleaning companies, the hospitality sector, private security services, and waste & facility management services.
7. The Healthcare workplace setting, including health centers, hospitals, private clinics, medical laboratories, and healthcare headquarters.
. The National Security workplace setting, including Qatar Armed forces, military, and police.9.The Public service workplace setting, including ministries and other entities offering public services such as education.

Results
During the period ranging from March 1 st , 2020 to July 28 th , 2020, a total of 477,194 individuals were tested for COVID-19, out of which, 109,597 tested positive.Case investigation data identi ed 54,584 cases belonging to a workplace cluster, with 10 or more positive cases.Table 1 shows the positivity rate in all workplace tested individuals was 27.6%.The highest test positivity was reported in workplaces related to the retail and wholesale trade sector as well as the construction and related sector (40.3%).The lowest positivity was reported in the health care sector (11.0%).
Table-2 shows that the positivity rate among tested employees in the private sector was signi cantly higher in comparison to the employee positivity rate in the public funded sectors (33.7% vs. 17.1%),Pvalue <0.001.2).
The total number of positive cases for these sectors represented 11.12% or 6,546 positive cases of the total 58,858 infected (Table 1).

Pattern Group C
The Oil & Gas and Health Sectors gradually increased in March and April, reaching a plateau in May and June, and then gradually decreased after that.These two categories shared some of the lowest infection rates, with 4,185 positive cases between March and July, representing 7.11% of the total 58,858 cases.They also corresponded to some of the lowest positivity rates among all categories, with 11.0% and 18.7% for healthcare and Oil & Gas, respectively.(Figure 3, Table 1).

Discussion
Qatar has taken general precautionary measures to prevent the spread of COVID-19.A number of those measures were related to the workplace.They varied from having a complete shutdown (e.g., Public transportation, Education, and some types of retail stores) to a mandatory 80% workforce to work from home, applied to all other businesses.The exceptions were the healthcare sector, national security, food industry, supermarkets, airport, and some major state construction projects that continued their work as usual.Additionally, the following employee categories were classed as high-risk and were urged to work remotely: employees over the age of 55 years, pregnant employees, employees with chronic diseases such as cardiovascular disease, cancer, diabetes, respiratory conditions and hypertension.
The study revealed that the highest positivity rates, irrespective of the frequency of testing, belonged to the retail and wholesale sector as well as the construction sector.Workers within the retail workplace setting, namely supermarkets, have been considered in the current outbreak as one of the occupational groups at increased risk of contracting COVID-19 disease in the workplace, given the necessary public interaction and frontline-focused nature of work . Both the construction and the retail sectors followed the same trend, with the number of cases reaching their peak in May.Although construction sites have no direct occupational or even public exposure, such as in retail and wholesale, the high number of cases might be related to environmental and educational factors.
Multiple elements in different areas can interact with each other, resulting in a cumulative risk that can affect and increase the worker's overall risk [ii] .For example, most construction companies use buses to transport workers, and at the start of the outbreak, there were no educational materials regarding infection prevention translated in the languages of the workers, who mostly come from Asian countries.Furthermore, Craft and Manual Workers live in crowded shared accommodation in constant proximity of one another, increasing the likelihood of COVID-19 transmission amongst them [iii] .Living in dormitory-style housing compounds challenges with implementing social distancing, and in consequence, increases the risk of spread of COVID-19.Workers also often gather for social and recreational activities, shared dining, and use shared equipment e.g.kitchen appliances.The accommodation type was considered in Qatar as one of the strong forecasters and substantial contributing risk factors for health problems amongst migrant workers [iv] .
Although the health care sector has been considered as a workplace with a high risk for occupational exposure to the infection, in this study, health care had the lowest positivity rate.This might be attributed to the enforcement of infection prevention and control and occupational safety measures such as continuously wearing masks, frequent handwashing, and constant availability of sanitizers.Another explanation could be the higher frequency of mandatory regular random testing of health care professionals.Health authorities have also put in place a range of teleconsultation services that proved quite effective in emergency response to deliver care while reducing the risk of contamination [v] .
A study highlighting work-related COVID-19 transmission in six Asian countries stressed the importance of work-related transmission of COVID-19 outside healthcare settings such as transportation or retail settings.Also, the proportion of healthcare workers (HCWs) among locally transmitted cases was smaller than non-HCWs in the included countries/areas [vi] .Those ndings likely support the e cacy of the use of PPE, screening, and knowledge about the pandemic in healthcare settings.HCWs are also strongly supported by international institutions to prevent and contain any outbreak within healthcare facilities: The World Health Organization has developed several speci c guidance documents regarding COVID-19 for HCWs, including rights, roles, and responsibilities with key considerations for safety and health.They have also established a risk assessment tool that is to be used by health care facilities to determine the risk of infection of all HCWs who have been exposed to a COVID-19 patient [vii] .
Periodic testing and isolation could also be one of the possible explanations for the low positivity rate associated with plateau patterns, which occurred in May and June, namely for the Health care sector and Oil & Gas industry.In addition, tracking back the infection source in healthcare settings is also more straightforward, and thus, containment is smoother.It is therefore crucial to protect essential workers not working in healthcare settings because their risk of infection is often under-estimated, especially when compared to the healthcare sector, and their employers might not always provide adequate Protective Equipment, training or screening [viii] .
Qatar began lifting restrictions in a four-phased approach that started in June.The systematic testing of employees who intended to return to work during the rst phase of lifting restrictions may explain the sharp increase in cases in the Public Service and the Accommodation & Food industries during this time.This screening initiative enabled the isolation of COVID-19 cases before the opening of public services, hotels, and restaurants to the public.
Lastly, the screened private funded sector was more affected by COVID-19 infections than the public funded sector.It is known that the private sector has higher percentages of workers who perform manual labor than the governmental sector.This disparity requires further investigation for the successful implementation of precautionary measures, given the discrepancy in the level of compliance and in the educational level of the employees between different sectors.These ndings also highlight the importance of tailored strategies for prevention and surveillance as well as a tailored communication approach at workplaces to convey consistent health messages that are easy and accessible for all segments of the population for an optimum health outcome.

Figure 1 Group
Figure 1 The data was analyzed to estimate and compare the positivity rate amongst screened individuals, as an indicator of the risk of developing COVID-19 infection across various workplace settings and occupations in the State of Qatar.
Subsequently, the surveillance data was mapped to the list of categorized workplace settings.The nal database created for this study consisted of patient demographics, workplace category, and COVID-19 laboratory results.

Table 1 :
Number of individuals tested, positive cases, and positivity rate per sector (original)

Table 2 :
Number of individuals tested, positive cases, and positivity rate per private funded sectors vs governmental funded sectors (original) Analysis of the total number of positive COVID-19 cases per month across the various workplace sectors identi ed three patterns in the peaks of the respective curves resulting in the different workplace settings being grouped into one of three groups, according to their peak patterns.
For the workplaces where the infection trends peaked in May, two patterns emerge.The construction, retail and Finance & Business sectors underwent a steep jump in numbers between April and May in comparison to the March -April period, and then gradually decreased in newly infected numbers throughout June and July.Alternatively, Transportation & Warehousing, Waste Management, and National Security Sectors followed a steady rate of increase up to May followed by a similarly steady decrease in the months of June and July (Figure1).With a total of 58,858 positive cases in the months ranging from March to July, Construction (35.07%),Retail (13.97%), and waste management (12.84%)collectivelyrepresentedapproximately 62%, or 36,420 cases out of all 11 categories (Table1).