The 2019 coronavirus pandemic illustrates the importance of public health response strategies for timely control of the outbreak. The failure of well-resourced countries such as the United States of America and the United Kingdom to adequately contain this pandemic highlights the complexity of large-scale containment measures and raises concerns for its impact in low-and middle-income countries (LMICs), where fragile health systems, competing priorities, poverty and crowding affect the capacity to manage health emergencies (Agyeman et al. 2020) . Indeed, a recent analysis of health security capacities in the context of COVID-19 showed that many LMICs are not operationally ready to prevent, detect, or control an outbreak (Kandel et al. 2020) . In fact, public health measures useful in other settings can negatively impact disadvantaged people in LMICs. For example, many migrant workers found themselves without jobs after the announcement of the India lockdown, compelling them to unexpectedly return home on crowded trains and buses with transmission implications (Pulla 2020) . However, the rapidly increased access to mobile phones and smartphone technology in health care staff and amongst citizens provides huge potential for public health workers, frontline clinicians and institutions to communicate and act swiftly in a setting of rapidly changing COVID-19 guidelines (Wallis et al. 2017) . In this article, reflecting on worldwide initiatives as well as our experience at Tygerberg Hospital (TBH) in the Western Cape province of South Africa, we discuss three ways in which mobile phone communication helps support patient care and disseminate information during the COVID-19 pandemic.
Since 2010, the World Health Organization (WHO) launched several calls to scale-up affordable and practical health technologies in less resourced settings (WHO 2015 (WHO -2017 .
Today, mobile apps are widely used, thus enabling healthcare workers to use their smartphone to share information with and request opinions from specialists, public health J o u r n a l P r e -p r o o f institutions and governmental agencies. In addition, these apps allow individuals and groups with different roles and responsibilities to rapidly communicate. In the COVID-19 and other infectious diseases epidemics, such as diphtheria and measles, medical groups from TBH, the second largest hospital in South Africa, have successfully used broadcast groups to rapidly communicate key issues and guidelines. Group members include medical, nursing, security, administrative, and laboratory staff as well as the ambulance service, disaster management experts and provincial public health officials. Communication is overseen by a medical manager and excludes patient identifying details.
Medical facilities in LMICs are generally spread over several buildings in large areas. These facilities operate like villages with thousands of medical personnel units working together on any given day. A sudden increase in patients requires localized reorganization and rapid communication between staff members and facilities to effectively handle emergency situations while receiving continuously updated information on relevant protocols. Local referral for acute care and clinical review can be conducted through free apps, such as Vula mobile (vulamobile.com), a healthcare app that connects primary healthcare workers with oncall specialists in South Africa. This start-up is now supported by the South African National Department of Health and is being rolled out across all nine provinces. In most African countries, intensive care unit (ICU) beds and personnel trained in critical care are limited to tertiary hospitals. Up-to-date information on the availability of ICU beds in the nearest tertiary hospital can be shared daily in designated mobile phone groups. This facilitates the expeditious transfer of patients and judicious use of ambulance services (Salman et al. 2020 ). Finally, in many LMICs, community health workers are integral in the primary healthcare system as they liaise between communities and healthcare facilities. These community workers are generally based in small hospitals in underserved areas. Often, they will be the first point of contact for ill people in the community, stressing the importance of keeping them informed on containment measures, case definitions, the spread and clinical characteristics of disease and referral pathways. Previous studies show that the successful J o u r n a l P r e -p r o o f use of mobile phone interaction between community health workers and hospital-based physicians can address health issues related to maternal and child health, family planning, infectious diseases and trauma (Braun et al. 2013; Anstey Watkins et al. 2018; Feroz et al. 2020 ). In addition, having clinical guidelines on mobile phones, in a structured interactive workflow, can reduce community health workers' errors in diagnosis and management by more than one third (Florez-Arango et al. 2011).
Monitoring cases as COVID-19 spreads appears crucial in order to contain the impact of the pandemic, to facilitate rapid implementation of isolation measures, to perform epidemiologic research on the origin and spread of the outbreak and to communicate the characteristics of high risk patients. Collecting data can be difficult in rural areas where infrastructure and communication channels are limited. By supporting direct communication between frontline workers and program managers, mobile phones can be a gamechanger (Table 1 ). In addition, if inadequate laboratory capacity requires clinical case definitions of suspected cases, rapid and clear communication between clinicians and public health agencies is central to effective monitoring. Cell phone messaging technology was effectively used for community epidemic surveillance in peripheral health facilities during the Sierra Leone Ebola virus epidemic (Jia and Mohamed 2015) and for rabies surveillance in Tanzania (Mtema et al. 2016) . Further, the dispatch of mobile phones led to a functional infectious disease surveillance system after the Sichuan earthquake in China (Yang et al. 2009 ). Whenever possible, mobile phones with global positioning system capacity can be used to integrate coordinate data to track cases in a high spatial resolution. Contract tracing has been used for several infectious disease outbreaks, including the Ebola epidemic (Sacks et al. 2015) . Both China and South Korea have achieved sustained COVID-19 epidemic suppression while using mobile phone apps aimed at instantaneous digital case and contact tracing for restrictions on movement and recommendations on risk-stratified quarantine. A mathematical simulation study suggested J o u r n a l P r e -p r o o f that a mobile app is the best way to implement fast and efficient contact tracing in the COVID-19 pandemic (Ferretti et al. 2020) . The South African government has recently partnered with cell phone companies to track mobile location data to trace contacts of an infected person for possible testing and quarantine (Table 1) .
The mobility and popularity of mobile technologies means that most people always have their The mHealth Assessment and Planning for Scale Toolkit, established through a collaboration between the United Nations Foundation and the WHO, is specifically aimed at facilitating successful scaling up of mobile health products for long-term sustainability (WHO 2015).
In the evolving COVID-19 pandemic, TBH personnel use mobile phone applications to communicate health messages on social distancing, cough etiquette and hand hygiene. Also, short video's sent to patients awaiting test results explain self-isolation. In addition, Voice over Internet Protocol (VoIP), using public WIFI, allows for calls to inform patients about test results without using mobile data. Further, messages discouraging irrational behaviour may counteract fake news. The messages are often sent by a healthcare provider known to the recipient, which likely increases their impact and limits misinformation and stigmatizing of J o u r n a l P r e -p r o o f patients. Since many healthcare workers in LMICs communicate with their (chronic) patients via mobile phone messages, this route can now also be used to remotely monitor patients for acute and chronic conditions, particularly when combined with video conferencing. However, the appropriateness of the communication platform and the type of information the doctor can share must be considered to ensure that boundaries of doctor-patient interaction do not become blurred.
In conclusion, it is evident from these three examples that mobile phones have helped healthcare workers in LMICs in data collection and reporting, organization of their workflow, and communication with other healthcare workers, public health institutions and patients.
Therefore, we recommend that crisis management plans to deal with the COVID-19 pandemic in LMICs strongly consider incorporating a centrally coordinated reporting and communication system using mobile phones. This may require the delivery of mobile phones to healthcare workers without their own devices. Access to public WIFI may be a limiting factor. Other challenges include ethical concerns around patient privacy and consent and concerns regarding equipment maintenance (Ferretti et al. 2020) . Familial sharing of phones and the possibility that individuals own multiple SIM cards or mobiles can affect the accuracy of information sharing and lead to privacy issues. Also, there are concerns related to the possible leakage of medical information via contact tracing apps. The purpose of an automated decentralized contact tracing system is to identify contacts of a COVID-19 case, inherently requiring at least a limited amount of personal information potentially vulnerable to unauthorized access (Bengio et al. 2020) . A scoring method or scale to objectively assess app privacy could be a key tool for systematically comparing apps and make decisions on their use in specific settings (Benjumea et al. 2020) . Finally, careful precautions must be taken to avoid mobile phones themselves being a vector for virus transmission since previous data show that respiratory viruses, including e.g. influenza virus, are found on up to 38% of health-care workers' mobile phones (Pillet et al. 2016) . The safe use of mobile phone devices and protecting personal health information transmitted over mobile phones is J o u r n a l P r e -p r o o f essential, as is ensuring that we utilize every resource available in settings where the preparedness to respond to outbreaks is relatively weak.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
No ethical approval was required.
All the authors have no conflict of interest to declare.
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Direct availability of a reliable response to individual concerns prevents the spread of fake news and reduces public anxiety.
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