A Systematic Review and Recommendation of Software Architectures

for SARS-CoV-2 Monitoring

Kay Smarsly

, Yousuf Al-Hakim

, Patricia Peralta

, Silvio Beier

and Claudia Klümper

Institute of Digital and Autonomous Construction, Hamburg University of Technology, Germany

Chair of Urban Bioengineering for Resource Recovery, Bauhaus University Weimar, Germany

Laboratory of Environmental Analysis, Department HAM 2, Hamm-Lippstadt University of Applied Sciences, Germany

Keywords: SARS-CoV-2, COVID-19, Wastewater, Monitoring, Surveillance, Software Architectures.

Abstract: The coronavirus disease 2019 (COVID-19) is a highly infectious respiratory disease caused by the severe

acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2), which has led to the ongoing global pandemic with

more than half a billion cases worldwide. Response measures to COVID-19 outbreaks suffer from lagging

between detecting and reporting COVID-19 cases and by underreporting. By contrast, using wastewater

allows detecting SARS-CoV-2 ribonucleic acid (RNA) in human feces, serving as a timely and reliable basis

for devising effective measures to prevent and control COVID-19 outbreaks. As a technological basis,

software systems for monitoring SARS-COV-2 RNA in wastewater are required, which are capable of (i)

interlinking COVID-19-related data from different sources, (ii) providing user interfaces with remote access,

(iii) implementing software design concepts that are well-established, and (iv) deploying on-demand

SARS-CoV-2 data analysis. To ensure reliable operation, it is crucial to set up SARS-COV-2 monitoring

systems based on sound software architectures. This paper systematically reviews and categorizes software

architectures for SARS-CoV-2 monitoring systems, considering journals, book series, and conference pro-

ceedings indexed in the Scopus database. Then, a software architecture for SARS-CoV-2 monitoring systems

is proposed. In future work, the proposed software architecture may be implemented and validated for

SARS-CoV-2 monitoring.

1 INTRODUCTION

The global pandemic of the coronavirus disease 2019

(COVID-19), with hundreds of millions of confirmed

cases, has caused an ongoing health crisis affecting

countries, which are facing COVID-19-related chal-

lenges that have triggered severe social and economic

consequences. The COVID-19 cases reported to

health authorities, together with COVID-19-related

hospitalizations and death rates, are key metrics used

to devise response measures to COVID-19 outbreaks

(Huber and Langen, 2020). However, the practice of

relying on reports of COVID-19 key metrics when

devising response measures comes mainly with two

downsides. First, the time period between detecting

and reporting COVID-19 cases to public health au-

thorities is relatively long (Cheng, et al., 2021). Sec-

ond, not all infections are detected and/or reported,

entailing high rates of underreported COVID-19

https://orcid.org/0000-0001-7228-3503

cases (Schneble, et al., 2021). As a result, the timeli-

ness and the effectiveness of response measures are

limited, having a non-negligible effect on public

health and on the economy.

To overcome the limitations of the current

practice, the severe acute respiratory syndrome

coronavirus 2 (SARS‑CoV‑2), causing COVID-19,

may be monitored in wastewater (Tandukar, et al.,

2022). The SARS-CoV-2 RNA can be detected in

human feces days to a week before the onset of

symptoms (Wölfel, et al., 2020), thus serving as a

proactive approach towards identifying potential

COVID-19 outbreaks and complementing the

COVID-19 metrics reported to public health

authorities (Nag, et al., 2022). In general, genomic

monitoring of viruses in wastewater has proven to be

a valuable tool for detecting and identifying variants

of concern and for establishing early warning systems

to support response measures on a scientifically

Smarsly, K., Al-Hakim, Y., Peralta, P., Beier, S. and Klümper, C.

A Systematic Review and Recommendation of Software Architectures for SARS-CoV-2 Monitoring.

DOI: 10.5220/0011593000003414

In Proceedings of the 16th International Joint Conference on Biomedical Engineering Systems and Technologies (BIOSTEC 2023) - Volume 5: HEALTHINF, pages 211-217

ISBN: 978-989-758-631-6; ISSN: 2184-4305

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

211

sound basis (Karthikeyan, et al., 2022). As a

consequence, response measures may be devised

earlier and more goal-driven, causing milder social,

economic, and cultural impacts as compared to the

current practice. For monitoring SARS-CoV-2

variants, influent samples are collected from

wastewater treatment plants and analyzed in

laboratories using reverse transcription quantitative

real-time PCR (RT-qPCR) and/or genomic

sequencing. To devise response measures as precisely

as possible, results achieved by SARS-CoV-2

monitoring must be correlated with data sets (e.g.

COVID-19 metrics) stemming from other data

sources.

To efficiently and accurately correlate the results

achieved by SARS-CoV-2 monitoring with data from

other sources, software systems need to be

implemented that are capable of (i) interlinking

COVID-19-related data from third parties, (ii)

providing user interfaces with remote access, (iii)

implementing software design concepts that are well-

established, and (iv) deploying on-demand data

analysis. Hence, a software architecture must be

defined, on which SARS-CoV-2 monitoring systems

may be built. Therefore, this paper systematically

reviews software architectures of SARS-CoV-2

monitoring systems, and of monitoring systems in

general, considering peer-reviewed journals, book

series, and conference proceedings.

The remainder of this paper is organized as

follows. First, the research methodology of the review

is described. Second, the results of the systematic

review are presented, and requirements of SARS-

CoV-2 monitoring systems are identified. Third,

based on a discussion of the results, a software

architecture for SARS-CoV-2 monitoring systems is

proposed. Finally, conclusions are drawn, and a brief

outlook on future research is presented.

2 RESEARCH METHODOLOGY

To ensure high quality of the literature screened in the

systematic review, journals, book series and confer-

ence proceedings indexed in the Scopus database are

used (Elsevier, 2022). The review includes literature

published between 2019 to 2022 because the first

COVID-19 case was registered in December 2019.

The research methodology follows three main steps,

(i) data collection, (ii) data organization, and (iii) data

analysis. In the first step, data collection, two search

strings are used, and the first search string is (“soft-

ware architecture” and (“monitoring” or “surveil-

lance”)). Owing to the novelty of SARS-CoV-2 mon-

itoring, SARS-CoV-2-related terms are omitted in the

first search string, i.e. the systematic review starts

with software architectures for monitoring and sur-

veillance applications in general, which results in an

initial search result of 1964 papers. The second search

string is (“software architecture” and (“SARS-CoV-

2” or “covid*” or “corona”)), covering literature on

software architectures for SARS-CoV-2 monitoring,

including monitoring efforts based on wastewater, as

well as literature reporting on software architectures

for SARS-CoV-2 platforms without monitoring fea-

tures, leading to 39 search results.

In the second step of the research methodology,

data organization, the results are subject to inclusion

and exclusion criteria, to ensure high quality of the

search results. It should be noted that, in general,

research papers that consider software architectures

of monitoring systems as well as literature reviews

that summarize software architectures for monitoring

systems are included. Additionally, papers written in

different languages are included. The primary

exclusion criterion is related to the question whether

the software architecture has been described in a way

that allows a clear identification for the systematic

review.

In the third step of the research methodology, data

analysis, the following research question is to be

answered: “What types of software architectures have

been implemented for SARS-CoV-2 monitoring

systems?” When answering the research question,

identified literature is analyzed, starting from a

broader analysis of monitoring system architectures

in general, ending up in architectures of systems

specifically designed for SARS-CoV-2 monitoring.

The research methodology is visualized in Figure 1.

3 REVIEW RESULTS

Regarding the first search string, i.e. monitoring sys-

tem architectures in general, from 1964 papers ini-

tially found, 100 papers are relevant to the review.

Regarding the second search string, i.e. monitoring

system architectures related to SARS-CoV-2 moni-

toring, from 39 papers initially found, 3 papers are

relevant to the review. The software architectures of

the monitoring systems presented in the papers found

from the first search string are categorized in Figure

2 and described in the following subsection, followed

by a description of the software architectures pro-

posed for SARS-CoV-2 monitoring systems.

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Figure 1: Research methodology.

3.1 Monitoring System Architectures

in General

As can be seen from Figure 2, the software architec-

tures used for implementing monitoring systems are

characterized by four predominant design patterns,

shown in Figure 3, which are materialized in four cor-

responding software architectures,

 the layered architecture,

 the client-server architecture,

 the microservice architecture, and

 the gateway architecture.

The software architectures used for implementing

monitoring systems will be described in the following

paragraphs. For further details on the software archi-

tectures and the underlying architectural design pat-

terns, the interested reader is referred to Fowler

(2002). From Figure 2, it is remarkable that the archi-

tectural design patterns of most software architectures

are hybrid or uncategorizable, the reason of which

will be addressed in the discussion section.

The layered architecture is most frequently used.

The layered architecture consists of three layers, the

presentation layer, the domain layer, and the data

source layer. The presentation layer ensures

interactions between users and the monitoring

Figure 2: Categorization of architectural design patterns

used for implementing monitoring systems that have been

published between 2019 and 2022.

system, the domain layer contains the logic of the

monitoring system, such as validations of user

requests, and the data source layer enables

communication with a database (Fowler, 2002). The

layer-wise separation has multiple benefits to

monitoring systems, as each layer is understood as a

single, independent unit. The separation is

particularly useful for comprehensive monitoring

processes with various parties involved in monitoring

or with respect to a substitution of layers, e.g. in case

of updates of monitoring system elements.

The client-server architecture comprises two

main elements, client and server. The client requests

data, services, or other resources from the server. The

server answers the requests and provides the

corresponding results and resources to the client.

Multiple clients may be connected to a server, where

not all clients need to be situated in the same network.

Since the client-server architecture centralizes data

within a monitoring system, a distinct advantage of

the architecture, besides security aspects owing to a

central server, is the ease of maintenance. Centralized

data not being distributed over several systems can

easily be managed, as compared to decentralized data.

The microservice architecture is used in various

recent monitoring systems. The most important

characteristic of the microservice architecture is the

“componentization” through microservices.

Essentially, microservices are small software

components that can be deployed, scaled, and tested

independently (Thönes, 2015). The componentization

through services allows independent deployment

with services being independently scalable and being

written in different programming languages. The

microservice architecture is therefore particularly

helpful for comprehensive, heterogeneous

monitoring systems with multiple parties involved in

monitoring.

A Systematic Review and Recommendation of Software Architectures for SARS-CoV-2 Monitoring

213

The gateway architecture encapsulates decoupled

elements of a monitoring system. The gateway acts as

an interface, through which clients may request a

service from a server. Monitoring systems based on

the gateway architecture are structured clearly, since

coordination and communication are managed by the

gateway. The gateway architecture has advantages

when implemented as a physically distributed system

because system changes do not affect every element,

and only the gateway needs to be adapted to the

changes.

3.2 Monitoring System Architectures

for SARS-CoV-2 Monitoring

The three SARS-CoV-2 monitoring systems identi-

fied in the systematic review implement the layered

architecture. Regarding the research topic, Tabbiche,

et al. (2021) propose a modeling tool for designing

applications that monitor real-time context infor-

mation. A prototype application, using a 4-layered ar-

chitecture, is presented in a pervasive environment

that tracks the movements of persons who have tested

positive, to anticipate COVID-19 contaminations.

Sethi and Pal (2021) introduce a monitoring system

for detecting COVID-19 exposure in public transpor-

tation vehicles. The monitoring system is imple-

mented on three layers, where a cloud layer and a user

layer are connected through a communication layer.

Finally, the monitoring approach pursued within

health care software proposed by De Moura Costa, et

al. (2022) aim to evaluate performance metrics re-

lated to COVID-19, such as latency, throughput, and

send rates in different locations. Two layers with mul-

tiple sub-layers and individual services have been im-

plemented, and privacy, scalability, and latency re-

duction have been considered important requirements

when choosing the layered architecture.

4 DISCUSSION AND

RECOMMENDATION

From the systematic review, it can be concluded that

the software architectures of monitoring systems

strongly depend on the monitoring objective. In gen-

eral, the layered architecture is most frequently used,

as it is easy to implement, modular, and allows sub-

stituting layers (i.e. elements of the system).

As mentioned earlier, it is apparent from Figure 2

that most architectures proposed for monitoring sys-

tems in general are hybrid or uncategorizable. A rea-

son, as expert surveys indicate, is that many monitor-

ing systems have been implemented from a pragmatic

engineering standpoint, sometimes in a trial-and-error

manner, without following professional software de-

sign concepts from a computer science point of view.

Regarding software architectures explicitly pro-

posed for SARS-CoV-2 monitoring, the layered ar-

chitecture has been used in all papers found in this

review. It is evident from the systematic review that

software architectures for SARS-CoV-2 monitoring

systems have rarely been reported because of the

novelty of the research problem. In addition, the

urgency of this matter has resulted in SARS-CoV-2

monitoring systems being implemented without

explicit architectural design and/or without reporting

the software architectures in scientific literature.

Taking the results summarized above as a starting

point, the software requirements relevant to SARS-

CoV-2 monitoring systems will be described in the

following subsection. Thereupon, a software

architecture for SARS-CoV-2 monitoring systems

will be proposed.

4.1 Software Requirements for

SARS-CoV-2 Monitoring Systems

To design the software architecture for SARS-CoV-2

monitoring systems, functional and non-functional

requirements are considered. The following discus-

sion will exemplarily focus on designing a prototype

SARS-COV-2 monitoring system within the

“CoMoTH” project using wastewater at 23

wastewater treatment plants in the Free State of Thu-

ringia, Germany (CoMoTH, 2022). Project partners,

such as federal, state, and local health authorities as

well as companies, are involved in the design process

to provide advice according to their needs in data

analysis and visualization.

Figure 3: Layered, client-server, microservice, and gateway architecture.

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As for the functional requirements, the

monitoring system must be accessible through web

browsers and must provide user-friendly

visualizations of the data and of the data analysis

results, the latter based on well-established

mathematical statistics as well as on artificial

intelligence techniques. Representing another

functional requirement, the needs of the project

partners as well as the needs of the general public

(being users of the monitoring system) are to be

implemented. A further functional requirement is the

ability to couple the wastewater monitoring system

with COVID-19-related software platforms operated

by third parties. The German Government’s central

scientific institution in the field of biomedicine, the

Robert Koch Institute (RKI), provides a digital

interface used by hospitals, laboratories, and test

centers to forward COVID-19-related data to the

RKI, which is to be interfaced with the proposed

monitoring system. Furthermore, the monitoring

system must be modular, allowing for easy

modifications. The functional requirements are

summarized as follows: The software architecture

must ensure that the monitoring system

 is accessible through web browsers and pro-

vides user-friendly visualizations of the data

and of the data analysis results to be achieved

based on well-established mathematical statis-

tics as well as on artificial intelligence tech-

niques,

 is, in a first step, adjusted to wastewater treat-

ment plants in Thuringia, Germany, while the

concept is generally valid,

 implements the needs of the project partners

and of the general public (being users of the

monitoring system),

 is modular, allowing for easy modifications,

and is interlinked with COVID-19-related soft-

ware platforms operated by third parties.

In addition to the functional requirements listed

above, the architecture must ensure that the following

non-functional requirements will be met by the

monitoring system. The non-functional requirements

are basically the quality constraints that the

monitoring system must satisfy:

 Usability: The users are enabled to perform the

monitoring tasks safely, effectively, and effi-

ciently.

 Integrity: Data accuracy and consistency are

ensured when storing, processing, and retriev-

ing monitoring data.

 Extensibility: Without much effort, the moni-

toring system is expandable.

 Portability: The monitoring system can be im-

plemented on different platforms.

 Security: The monitoring system is protected

against disclosure, theft and damage of data

and disruption or misdirection of services.

 Reliability/availability: For the specified peri-

ods of time (reliability) and at the specified in-

tervals of time (availability), the monitoring

system functions under stated conditions.

 Maintainability: The monitoring system is eas-

ily maintainable to correct defects, to repair or

replace faulty software components, and to

maximize reliability.

 Robustness: The monitoring system copes

with errors during execution and with errone-

ous input.



Further non-functional requirements known

from software engineering must be met, such

as scalability, performance, efficiency, safety,

flexibility, and reusability.

4.2 A Software Architecture for

SARS-CoV-2 Monitoring Systems

As an outcome of the review and drawing from the

requirements summarized in the previous subsection,

the following software architecture is proposed for

SARS-CoV-2 monitoring systems and recommended

for the specific SARS-CoV-2 monitoring system

described above. Unlike software architectures

identified in the review, a model-view-controller

(MVC) architecture is proposed, which divides a

software system into three elements, model, view,

and controller, as shown in Figure 4. The model,

independently from user interfaces, contains domain

logic and manages the data of the system (e.g. in form

of one or more databases that contain data relevant to

SARS-CoV-2 monitoring). The view acts as an

interface between users and the application, where

different views may be devised, e.g. through web

browsers, remote application programming interfaces

(APIs), or command-line interfaces. Moreover, the

views can be tailored to a user or a user group (such

as federal, state, and local health authorities or the

general public), and the same information provided

by the model can be presented differently, depending

on the view. Finally, the controller receives user

inputs (such as requests regarding SARS-CoV-2

data), performs interactions with the model, and

initiates view updates.

The MVC architecture specifically supports the

processes relevant to SARS-CoV-2 monitoring and

the specific needs of the users and user groups

involved in monitoring. As can be seen from Figure

A Systematic Review and Recommendation of Software Architectures for SARS-CoV-2 Monitoring

215

4, using a web browser, a user interacts with a

dashboard provided by the view (1) to visualize data

and to conduct online data analyses. Thereupon, the

view alerts the controller (2), which contacts the

model to retrieve the data and conducts the analyses,

applying the algorithms that are available to the view.

Then, the controller updates the model (3) and sends

the requested data and the analysis results to the view

(4), which updates the visualization in the dashboard

for the user (5).

In summary, every element can be designed,

implemented, and validated independently from each

other because of the strict separation of the elements.

The separation of view and model is most important,

as different presentations, tailored to different user

groups, may be implemented independently from the

model. Vice versa, different databases or other

sources for integrating SARS-CoV-2 data may be

included into the systems (such as RKI databases or

other databases operated by health authorities)

without affecting the presentation or the controller,

which handles user requests and makes use of

algorithms (such as AI algorithms) to analyze the data

of the model before passing the results to the view.

Moreover, the view may provide different

presentations, tailored to different users or user

groups, as the presentation depends on the model, but

the model does not depend on the presentation.

Figure 4: Proposed software architecture for SARS-CoV-2

monitoring systems.

5 SUMMARY AND

CONCLUSIONS

Response measures to COVID-19 outbreaks primar-

ily depend on the number of COVID-19 cases, on

hospitalization rates, and on the death rates reported

to health authorities. Reporting is a practice that de-

pends on timely and reliable reactions (from infected

individuals, test centers, and local authorities). The

current practice thus suffers from lagging between de-

tecting and reporting COVID-19 cases and by un-

derreporting. By contrast, using wastewater allows

detecting SARS-CoV-2 RNA in human feces, serving

as a timely and reliable basis for devising effective

measures to prevent and control COVID-19 out-

breaks. To ensure reliable operation of SARS-CoV-2

monitoring systems, it is crucial to design monitoring

systems based on sound software architectures. This

paper has systematically reviewed and categorized

software architectures for monitoring systems in gen-

eral and for SARS-CoV-2 monitoring systems in par-

ticular, considering journals, book series, and confer-

ence proceedings indexed in the Scopus database that

have been published between 2019 and 2022. Build-

ing upon the findings achieved in the review, a soft-

ware architecture for SARS-CoV-2 monitoring sys-

tems has been proposed.

From the systematic review, it has been concluded

that the software architectures of monitoring systems

strongly depend on the monitoring objective. Regard-

ing software architectures of monitoring systems in

general, most architectures are hybrid or uncategoriz-

able. A reason, as expert interviews indicate, is that

many monitoring systems have been implemented

from a pragmatic engineering standpoint, sometimes

in a trial-and-error manner, without conducting pro-

fessional software design concepts from a computer

science point of view. With respect to SARS-CoV-2

monitoring systems, only very few software architec-

tures have been reported, which may be attributed to

the novelty of this matter.

Considering the results of the review and building

upon the analysis of the software requirements relevant

to SARS-CoV-2 monitoring systems, an architecture

for SARS-CoV-2 monitoring system has been be pro-

posed. The architecture is based on an MVC pattern

because of its modularity and the separations of view

and controller as well as of view and model, the latter

being fundamental, as different models may be ex-

changed and integrated into a SARS-CoV-2 monitor-

ing system independently from the view. In future

work, the authors aim to implement the proposed

SARS-CoV-2 monitoring system and, using the moni-

toring system, to validate the proposed approach.

ACKNOWLEDGEMENTS

This research is partially funded by Bauhaus Univer-

sity Weimar, Germany, under award number

2360200276-2/21, which is gratefully acknowledged.

The authors would also like to thank the Free State of

Thuringia, Germany, as this work has partially been

conducted within the framework of the CoMoTH pro-

ject, funded by Thüringer Aufbaubank under grant

number 2021 FE 9143/44. Finally, the authors would

like to record their deep gratitude for the invaluable

HEALTHINF 2023 - 16th International Conference on Health Informatics

216

support and suggestions provided by the research

teams at Robert Koch Institute.

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