The MONITOR Ecosystem: A Digital Health Intervention for the Early Detection, Control, Follow-Up, and Management of COVID-19 in Mexico

In fighting infectious disease outbreaks, a basic epidemiological principle is to detect cases quickly and to isolate each case, to interrupt transmission. This principle has been the cornerstone of the Carso Group (CG) COVID Protocol, a systematic blue-print for the reopening of operations of workplaces in the context of ongoing disease transmission in Mexico. The CG comprises over 50 companies with approximately 180,000 employees engaged in economic activities including telecommunications, retail, construction, banking, mining, and manufacturing, among others. To cope with the COVID-19 pandemic within the CG, the Carlos Slim Foundation designed, developed and implemented MONITOR, a digital health ecosystem comprising a mobile phone application, web portal, and analytics platform, to assess the infection risk of each employee, follow-up their health status, and detect early symptoms of COVID-19. MONITOR provides daily notifications for any suspected cases and activates a COVID-19 testing request and follow-up of results. This intervention helps rapidly identify and isolate suspected cases, as well as follow-up of work and family contacts, to prevent further outbreaks. Use of MONITOR has thus enabled containment of COVID-19 in workplaces and safe return to work. MONITOR is an example of the implementation of public health practices in workplaces and can serve as the basis for larger deployment in population-wide settings.

banking [19]. CG comprises more than 50 companies, with operations in over 5000 locations throughout Mexico and approximately 180,000 employees. CG companies are located in 1333 municipalities (54.2% of the total municipalities) within the 32 Mexican states, and 83% of these are located in 20 metropolitan areas: 45.6% in the Mexico City Metropolitan Area, 4.1% in Puebla-Tlaxcala, 4.1% in Guadalajara, 3.9% in Tijuana, and 3.8% in Monterrey.
The COVID-19 pandemic has affected all economic activities globally, forcing governments and entities to implement actions to contain its transmission [20][21][22]. Among the most important of these, most economic activity has shifted to telework, with the exception of activities that are deemed essential [12,15,23]. Importantly, some CG companies are engaged in essential economic activities in areas such as telecommunications, banking, mining, and energy. In addition, CG employees have varying levels of risk, either owing to older age or underlying non communicable diseases (NCDs). Some employees are more vulnerable because the nature of their work requires constant interaction with others, such as those working in retail stores, or because their household or workplace is located in a municipality with a high risk of contagion.
In response to the COVID-19 pandemic, the CG Board of Directors commissioned the Carlos Slim Foundation (CSF), a non-profit independent organization linked with the Group, to design and implement a comprehensive response protocol to contain the spread of COVID-19 in the workplace, with the goal of protecting the health of employees and their families, as well as suppliers and clients.
The CSF was founded in 1986. Its aim is to address social inequalities by improving quality of life for the most vulnerable populations by training human resources and promoting greater opportunities. The scope of work of the CSF spans education, employment, health, nutrition, social justice, culture, human development, natural disaster support, economic development, and environmental protection [24].
The Carso COVID Protocol is the result of the abovementioned efforts. The protocol is divided into two components, launched at different times during the COVID-19 pandemic in Mexico; Annex 1 provides greater detail regarding the policies and recommendations outlined in the Protocol: • Prevention and containment of COVID-19, launched on March 13, 2020 • Safe return to work, launched on May 22, 2020.
The CSF has extensive expertise in the design, development, implementation, and scale-up of digital health (DH)-based solutions aimed at improving health care service delivery to strengthen primary care, with a strong focus on prevention [25]. Hence, the CSF convened a team of experts in different disciplines to design a COVID-19 digital health ecosystem to facilitate implementation of the Carso COVID Protocol.

Digital health in the response to viral outbreaks
One of the basic epidemiological principles in mitigating infectious disease outbreaks is to stop transmission through timely detection and isolation of cases [26]. Hence, leveraging DH contributes to an effective public health strategy to prevent and mitigate the spread of an infectious disease [27].
DH is the new paradigm in health care, defined as "the convergence of four disruptive technologies: 1) the use of digital platforms, connected through micro-services, 2) cloud-based services with robust infrastructure to support big data transactions, 3) use of inter-connected wearables, devices and tracers, and 4) connecting communities through mobile phone apps and social media.

Viral Outbreaks
4 These technologies are enhanced by Artificial Intelligence." [28]. The potential of DH has been demonstrated in detecting and mitigating infectious disease outbreaks and epidemics in countries worldwide [29]. Some examples of successful DH-based strategies include the 2014-2016 Ebola outbreak across West Africa [27] and the 2003 global outbreak of SARS-CoV [29]. In Mexico, there is evidence of the benefits of a mobile phone-based intervention to support surveillance during the H1N1 influenza pandemic in 2009 [30].
The current COVID-19 pandemic highlights the need for innovation in continuous surveillance, rapid diagnosis, and real-time contact-tracing of emerging infectious diseases. Health systems are structured around face-to-face medical visits, which involve direct interaction between patients and their health care providers [31]. This operating model can contribute to faster spread of infection among uninfected individuals, quickly overwhelming available critical care services [31,32]. Additionally, health care providers are at high risk of exposure to COVID-19 infection, which leads to reduced availability of skilled clinicians over time. When health care resources are strained to a breaking point, patient care may be compromised, which is associated with negative outcomes and increased mortality rates [33].
Given the aforementioned scenario, there is a window of opportunity to implement, expand, and integrate DH technologies across the health care system [34]. The use of digital platforms has become the primary means of communication whereby people, governments, organizations, and health institutions can communicate, work, interact, share and exchange knowledge and information, and generate data [35].
DH has become increasingly instrumental in the response of governments and organizations to COVID-19 [36]. DH solutions include, but are not limited to, telemedicine/telehealth, electronic medical records, public health surveillance leveraging on big data and AI algorithms, wireless health sensors, georreferencebased tracing technologies, mobile health applications (apps), and health analytics platforms for public health and clinical decision-making [33]. In the case of COVID-19, DH can offer real-time access to comprehensive individualized reliable data, to enable personalized monitoring and provide AI-based assistance. DH can also be implemented to access reliable data and information, participate in social media, use risk-based algorithms to support self-diagnosis, seek health professionals to receive clinical support, and maintain work activities, among other applications [35,37]. Table 1 shows some DH solutions that have been developed and are being used by institutions, governments, and NGOs around the world to prevent, manage, and mitigate COVID-19.

MONITOR digital health ecosystem
The first case of COVID-19 in Mexico was reported on February 27, 2020 [108,109]. Fully aware of the benefits of DH, the CSF had begun to work on the design of a robust response plan in January 2020. On March 13, 2020, the Carso COVID Protocol was launched, including a comprehensive set of actions and recommendations to prevent and contain COVID-19 in the workplace. As part of implementation of the Protocol, the CSF launched the MONITOR digital health ecosystem (MDHE), aimed at monitoring the wellbeing of CG employees and their families. 1 MONITOR was initially designed based on WHO and CDC guidelines, and its recommendations are in compliance with current regulations of Mexico's Ministry 1 Annex 1 provides a detailed description of the recommendations and actions in the Carso COVID-19 protocol. of Health. Furthermore, MONITOR has been continuously updated with the latest available scientific evidence. The MDHE comprises three interconnected platforms operating concurrently: a mobile phone application and a web portal for employees and their families to register and report symptoms on a daily basis, the Integrated Measurement for Early Detection (MIDO)-COVID Platform to assess NCDs and COVID-19 serological status among employees at worksites, and the Health Intelligence Platform with robust analytics to support decision making. Importantly, the MDHE is compliant with Mexico's regulatory standards in terms of confidentiality, security and privacy.

Prevention and containment of COVID-19 in the workplace
MONITOR enables the implementation of a COVID-19 prevention and containment strategy according to the following stepwise process: 1. An employee registers in MONITOR using either the mobile phone app or a secure web portal. During registration, the employee is asked to provide information on any existing NCDs.
2. On a daily basis, individuals report whether they have any symptoms and if so, describe those symptoms. Using a point-based risk algorithm, MONITOR automatically assesses and classifies each person's risk and provides immediate recommendations, as follows: a. No risk (no symptoms): the employee is encouraged to continue notifying on a daily basis.
b. Mild risk: the employee is encouraged to increase the number of notifications to twice a day and to continue monitoring.
c. Moderate risk: the employee is encouraged to increase notifications to twice a day and if necessary, to call a dedicated call medical center operating 24/7/365. d. Severe risk: the employee is encouraged to increase notifications to twice a day and to call a medical call center. In addition, an alert is triggered to the human resources (HR) department of the employee's company, to signal a potential complication.
3. At the medical call center, a general physician provides remote counseling, and assesses whether the employee requires a reverse transcription polymerase chain reaction (RT-PCR) test to confirm a diagnosis of COVID-19 infection, or whether they need to be referred for immediate medical assessment.
4. If a person is referred for an RT-PCR test, the general physician schedules an appointment at any of the CG-dedicated lab facilities in Mexico City and 27 cities throughout the country. Once the employee has been tested, they are instructed to remain in isolation until their test results are obtained, within 24-48 hours.

Upon confirmation of COVID-19 infection:
a. The employee receives a pulse oximeter for self-monitoring during the 14-day isolation period. The employee is required to notify symptoms via MONITOR.

Viral Outbreaks
b. The CSF epidemiology team, in coordination with company HR departments, conducts an outbreak investigation for each employee with confirmed COVID-19 infection, including tracing of all work and family contacts. A contact is defined as someone who has remained in close proximity (less than 2-meter distance) with the employee for at least 15 minutes while not wearing personal protective equipment; this definition is in line with WHO recommendations [9, 10].
c. All identified contacts are sent for confirmatory laboratory testing and are closely monitored throughout the period in which they are ill.
6. All collected data are available through the Health Intelligence Platform for real-time analytics, follow-up, and clinical support, for both HR departments and the CSF epidemiology team.

Safe return to work with MIDO-COVID
With ongoing transmission of SARS-CoV-2 during the phased reopening of nonessential activities in Mexico, a series of measures were implemented in CG's workplaces to ensure the safe return of employees. These measures are described in Annex 1.
There is ample scientific evidence demonstrating that the presence of comorbidities increase the risk of severity and complications of COVID-19, particularly cardiovascular disease, diabetes, hypertension, chronic lung or renal disease, and obesity [17]. In light of this evidence and building on previous experience [110][111][112], the CSF designed and developed the MIDO-COVID Digital Platform, aimed at assessing NCDs and COVID-19 serological status among employees resuming operations in the workplace.
Like MONITOR, MIDO-COVID is implemented following a stepwise process, performed by a MIDO expert 2 : 1. Registration of employees in MIDO-COVID, retrieving their data from the MDHE.
2. Measurement of weight/waist circumference and height, blood pressure, and capillary blood glucose, either fasting or random.
3. Performance of rapid antibody tests.
4. Recording of measurements and serologic test results.
5. Analytical algorithm with integrated risk profiling: a. NCDs profile with interpretation and recommendations.
b. Serology test results with interpretation and recommendations.
The MIDO-COVID Digital Platform automatically delivers certified serologic test results. Importantly, this assessment confirms the presence of NCDs and 2 In each workplace, employees are chosen to be trained as MIDO-COVID experts. These employees complete an online course in which they learn to measure weight, height, blood pressure, and capillary blood glucose; and how to record these measurements in the digital platform, perform serological tests, and provide brief counseling when informing employees of their test results. validates the self-reports provided by employees using the mobile phone app. Finally, in the case of active COVID-19 infection, the employee is quarantined and the contact tracing protocol is begun, as described above.
In sum, joint coordination of the HR department at each company with the epidemiology team at the CSF has enabled effective deployment of the Carso COVID Protocol through the use of MONITOR. Table 2 shows the main results of the MDHE as of October 31, 2020.

Permanent strategies following the current public health emergency
Given that the COVID-19 pandemic has changed the way that companies function, the CG intends to retain certain strategies to protect employees' health. The COVID-19 pandemic has provided an excellent opportunity to improve the workplace environment in terms of health and safety at every worksite. The CG is fully committed to providing every employee with all the preventive tools, measures, and strategies needed to maintain a physically and mentally healthy community. In this sense, the CSF encourages joining MONITOR together with MIDO, with the recognition that poor control of NCDs increases the risk for COVID-19 complications [113]. MIDO screening can facilitate early detection of type 2 diabetes, hypertension, and dyslipidemia, focusing specifically on predisease stages and early treatment. MIDO offers a systematic risk assessment of screened individuals, identifying those with a healthy, at-risk (pre-disease), or disease status [112].
Inter-connecting MONITOR and MIDO-COVID in a digital ecosystem allows HR personnel to identify COVID-19 positive employees or those with high-risk of complications. Daily information can be used to better monitor, diagnose, track and control employees' infection risk and overall health. Moreover, data are stored in a secure cloud, where it can be retrieved to generate predictive models for each company and type of workplace, as a strategy to better understand and control risk factors in each sector. Flexible schedules, in which employees alternate teleworking and working at a CG location when necessary, are very important. If an employee feels unwell, they must notify their direct manager and should not present to their work location. In worksite dining rooms, menus should be based on nutritional recommendations following the EAT-LANCET Commission on healthy diets and sustainable food production. Every meal is to be prepared according to the planetary health plate, characterized by at least 50% vegetables (fruits and vegetables) and the remainder comprising whole grains, plant-source protein, animal-source protein, dairy foods, and unsaturated plant oils [114].
Workplaces are implementing programs to promote wellbeing and healthy lifestyles among employees and their household members. In this way, the CG seeks to empower its employees through health promotion initiatives conducted by trained multidisciplinary health professionals in topics including nutrition, NCDs prevention, physical activity, vaccination, mental health awareness, and wellbeing.
As part of its response to COVID-19 as well as other novel pathogens, the CG plans to create emergency response teams and permanent communication via DH among HR departments across all CG businesses. Frequent intervention assessments will be carried out to gauge adherence to protocols and determine where improvements are needed.

Conclusions
This chapter describes the CG COVID-19 mitigation strategy within a corporate group in Mexico. Priorities for the CG during this outbreak have been to protect employees' health and wellbeing by implementing protocols and strategies based on scientific evidence. Consequently, occupational safety and health have taken on greater relevance in all kinds of workplaces.
First, our experience shows that Digital Health can be used to quickly identify people with any infection risk, during early stages. CG employees are empowered through advice and counseling using IT tools such as a mobile phone app or website. The MONITOR strategy has proven to be an effective intervention. The use of DH has been instrumental in outbreak control and maintaining workplace activities. Second, we have learned that the use of a Digital Health ecosystem is effective in detecting and controlling COVID-19 outbreaks in work settings.
This experience can be useful for other organizations in the process of implementing and operating digital health based strategies to cope with outbreaks of viral disease.

Appendix 1. The Carso COVID Protocol
To support the Carso Group (CG) COVID-19 response plan, the Carlos Slim Foundation prepared and designed the Carso COVID Protocol, called the "Recommendations and guidelines for the prevention and management of COVID-19 in an organization". The Protocol has two components, launched at two time points during the course of the pandemic: • Prevention and containment of COVID-19, launched on March 13, 2020 (Supplementary Table 1) • Safe return to work, launched on May 22, 2020 (Supplementary Table 2).
This Protocol is based on scientific evidence regarding infectious diseases and the most important available evidence regarding COVID-19 to date. Most recommendations are based on WHO and CDC guidelines and are continuously updated as new evidence becomes available.
The Protocol was designed with consideration for the needs of the different CG workplaces. Nonetheless, each company within the CG has adapted the recommendations to the operational needs of each workplace. For example, most employees in workplace settings that were not considered essential switched to teleworking whereas employees performing activities classified as essential implemented different schemes, such as staggered working schedules. It is noteworthy that the Protocol was implemented at all CG worksites.

Continuity of Operations Group
In each company, this refers to a team comprising employees with decisionmaking capacity. This group designs, coordinates, and establishes the organization's continuous operations policies and guidelines.
• Communicate general preventive measures.
• Ensure the implementation of proper cleaning and disinfection policies.
• Define and implement work-at-home policies and provide guidance to staff regarding their implementation to maintain operations.
• Monitor employees' health status and implement quarantine and isolation policies according to guidelines.
• Monitor the evolution of employees with COVID-19 infection in isolation.
• Update COVID-19 prevention and care policies according to the latest evidence and government regulations.

Communication strategies
Identifying the point of contact in each workplace and department to communicate new policies and guidelines.
• Communication of Protocol policies through available channels: billboards, intranet, email, social media, mobile phone text messaging, etc.
• Implementation of a "hotline" available to employees 24/7, to address any questions or request support.

General containment measures
This refers to general containment measures for employees.
Measures are classified according to risk: • General (employees, suppliers & visitors).
• Employees with any symptoms of respiratory infection.
• Employees diagnosed with COVID-19 (suspected or confirmed) and/or in contact with a confirmed COVID-19 case.

General preventive measures
This describes hygiene and physical distancing measures that must be implemented in each workplace.
The supplies needed to implement these policies are also listed. Recommendations for working from home are given.
• Placement of posters and communication materials.
• Availability of face masks at workplaces, as well as bins for their disposal.
• Equipment for cleaning staff.
• Use of 0.1% chlorine solution or 70% ethanol for disinfection of surfaces.
• Handwashing and use of alcohol-based hand sanitizer.
• Suspension of air conditioner use and proper ventilation measures.
• Staggered work schedules in confined or crowded workspaces.
• Working from home.
• Recommendations for vulnerable populations • Timely notification of symptoms.
• Establishment of a COVID-19 team in each workplace.

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The • Measures at the dining room entrance and restriction of access for employees who do not comply with policies.
• Use of personal protective equipment among dining room staff.
• Safe use of trays, glasses, and cups.
• Elimination of self-service areas, such as salad bars or shared condiments.
• Isolation of dining room staff with COVID-19 infection or symptoms.

Cleaning company staff
Describes policies and guidelines that all cleaning staff must comply with.
• Policies for work attendance.
• Use of uniforms and restrictions regarding jewelry and beards.
• Use of personal protective equipment.
• Use of 0.1% chlorine solution or 70% ethanol to disinfect surfaces.
• Suspension of air conditioner use and proper ventilation measures.
• Adequate disposal of garbage.

Travel, business meetings and events
Describes general policies for travel, meetings, and events. This section emphasizes the importance of transitioning to tele-or video conferences.
• Cancelation or restriction of national and international travel.
• Isolation policies after returning from essential travel.
• Suspension of conferences, events, or summits, regardless of their nature.
• Restriction of visitors and suppliers in the workplace.
• Promotion of tele-and video conferences.
• Restrictions regarding face-to-face work meetings.

Customer service workplaces
This section describes the general policies for workplaces that provide customer service, such as retail and post-sales services and banking.
• Use of face masks and personal protective equipment.
• Cleaning of workspaces, and use of 0.1% chlorine solution or 70% ethanol for disinfection.
• Identification and management of suspected cases of COVID-19 infection.
Call centers • Alternating work shifts to facilitate physical distancing.
• Identification and management of suspected cases of COVID-19 infection.
• Use of 0.1% chlorine solution or 70% ethanol to disinfect surfaces. • Adaptation of workspaces: ○ Screens and partitions between workstations.
○ Signs outlining requirements and recommendations posted in areas with high visibility.
○ Strategically located alcohol-based hand sanitizer dispensers that are constantly stocked.
• Sanitization and disinfection of workspaces.
Measures to reduce physical interaction • Staggered work shifts and working from home.
• Implementation of flexible work schedules.
• Protocols for interaction with suppliers and customers.
• Restriction of meetings and promotion of tele-and video conferences.

Measures to reduce risk of infection
• Organization of teams to supervise the correct application of basic preventive measures.
• Point-of-entry screening in each workplace.
• Identification and management of suspected COVID-19 cases during working hours.
Employee training and awareness campaigns • Permanent social media campaigns to raise awareness.
• Development and adaptation of content and materials: the CSF developed a web portal with curated information about COVID-19. As of October 31, the CSF has produced more than 150 informational materials including infographics, videos, and audio recordings to support CG companies in raising awareness about COVID-19.