Google search patterns monitoring the daily health impact of heatwaves in England: How do the findings compare to established syndromic surveillance systems from 2013 to 2017?

• Published in: Environmental research Vol. 166; pp. 707 - 712
• Main Authors: Green, Helen K., Edeghere, Obaghe, Elliot, Alex J., Cox, Ingemar J., Morbey, Roger, Pebody, Richard, Bone, Angie, McKendry, Rachel A., Smith, Gillian E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.10.2018
• Subjects: CLIMATIC CHANGE; DISEASE INCIDENCE; England; ENVIRONMENTAL SCIENCES; HEAT; Heat-related illness; Heat-waves; Hot Temperature; Humans; INTERNET; MEDICAL SURVEILLANCE; MONITORS; Morbidity; PUBLIC HEALTH; Retrospective Studies; Search Engine; Sentinel Surveillance; SYMPTOMS; Syndromic surveillance; Temperature; TIME DELAY; UNITED KINGDOM; England; Heat-related illness; Temperature; Syndromic surveillance; Heat-waves; Public health
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2018.04.002

One of the implications of climate change is a predicted increase in frequent and severe heatwaves. The impact of heatwaves on the health of the population is captured through real-time syndromic healthcare surveillance systems monitored daily in England during the summer months. Internet search data could potentially provide improved timeliness and help to assess the wider population health impact of heat by capturing a population sub-group who are symptomatic but do not seek healthcare. A retrospective observational study was carried out from June 2013 to September 2017 in England to compare daily trends in validated syndromic surveillance heat-related morbidity indicators against symptom-based heatwave related Google search terms. The degree of correlation was determined with Spearman correlation coefficients and lag assessment was carried out to determine timeliness. Daily increases in frequency in Google search terms during heatwave events correlated well with validated syndromic indicators. Correlation coefficients between search term frequency and syndromic indicators from 2013 to 2017 were highest with the telehealth service NHS 111 (range of 0.684–0.900 by search term). Lag analysis revealed a similar timeliness between the data sources, suggesting Google data did not provide a delayed or earlier signal in the context of England's syndromic surveillance systems. This work highlights the potential benefits for countries which lack established public health surveillance systems to monitor heat-related morbidity and the use of internet search data to assess the wider population health impact of exposure to heat. •Heat health-related Google search term frequency increased during heatwave events.•Google data correlated well with validated syndromic heat health indicators.•A similar timeliness was seen between daily Google and syndromic data in England.•Google search data could be of benefit in monitoring heat-related morbidity.