Digital public health surveillance: a systematic scoping review

Abstract

The ubiquitous and openly accessible information produced by the public on the Internet has sparked an increasing interest in developing digital public health surveillance (DPHS) systems. We conducted a systematic scoping review in accordance with the PRISMA extension for scoping reviews to consolidate and characterize the existing research on DPHS and identify areas for further research. We used Natural Language Processing and content analysis to define the search strings and searched Global Health, Web of Science, PubMed, and Google Scholar from 2005 to January 2020 for peer-reviewed articles on DPHS, with extensive hand searching. Seven hundred fifty-five articles were included in this review. The studies were from 54 countries and utilized 26 digital platforms to study 208 sub-categories of 49 categories associated with 16 public health surveillance (PHS) themes. Most studies were conducted by researchers from the United States (56%, 426) and dominated by communicable diseases-related topics (25%, 187), followed by behavioural risk factors (17%, 131). While this review discusses the potentials of using Internet-based data as an affordable and instantaneous resource for DPHS, it highlights the paucity of longitudinal studies and the methodological and inherent practical limitations underpinning the successful implementation of a DPHS system. Little work studied Internet users' demographics when developing DPHS systems, and 39% (291) of studies did not stratify their results by geographic region. A clear methodology by which the results of DPHS can be linked to public health action has yet to be established, as only six (0.8%) studies deployed their system into a PHS context.

Fig. 1. Flow diagram.

The overall process of article selection following PRISMA-ScR guideline.

Fig. 2. The most frequently addressed PHS themes.

The temporal trends of the two most prevalent themes of DPHS systems in the literature.

Fig. 3. The distribution of studies based on country and affiliation, mapped to different PHS themes.

a Top five countries and PHS themes. b The frequency of different combinations of affiliations, PHS themes and the average number of authors per country.

Fig. 4. The temporal trend of surveillance domains associated with a cross-tabulation of surveillance domains and social media platforms (darker shades represent smaller values).

Surveillance systems that utilized more than one platform were assigned to multiple, and the maximum allowed being five. Studies that investigated more than five platforms are mapped to the ‘Social Media Platform’ column.

Fig. 5. Data collection duration.

The differences in data collection duration across included studies and the proportion of articles within each time frame across all surveillance systems.

Fig. 6. The top charts illustrate the mapping between PHS topics and objectives [O], and findings [F] of their corresponding studies, the frequency of infoveillance/infodemiology studies for each topic, and the techniques used by the included publications to evaluate the effectiveness of their proposed approach in addressing the key objectives of a surveillance system.

The bottom charts represent the temporal trends of data analysis used by the included studies and the frequency of articles that identified each of the age/gender/place in their datasets.

Fig. 7. Data types and analysis methods.

The mapping between data types used by the included studies and the PHS systems, platforms, and the use of machine learning.

Fig. 8. The overall iterative process of a public health surveillance system.

The coloured phase in red highlights the key difference between traditional and digital public health surveillance. The summary of current limitations of research on DPHS discussed throughout this review, is mapped to and listed below each activity of the process.