Syndromic surveillance use to detect the early effects of heat-waves: An analysis of NHS direct data in England

G. S. Leonardi, S. Hajat*, R. S. Kovats, G. E. Smith, D. Cooper, E. Gerard

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)


Objectives: To investigate the effects of high ambient temperatures, including the summer 2003 heat-episode, on NHS Direct usage and its suitability as a surveillance tool in heat health warning systems. Methods: Analyses of data on calls to NHS Direct in English Regions in the period Dec 2001-May 2004. Outcomes were daily rates of all symptomatic calls, and daily proportion of calls for selected causes (fever, vomiting, diffi culty breathing, heat-/sun-stroke). Results: Total calls were moderately increased as environmental temperature increased; this effect was greatest in calls for young children and for fever. Total calls were moderately elevated during two summer heat episodes in 2003: calls specifically for heat/sun stroke increased acutely in response to these episodes. No association was apparent between environmental temperature and proportion of calls for vomiting and difficulty breathing. Conclusions: Calls to NHS Direct are sensitive to daily temperatures and extreme weather. NHS Direct is timely and has great potential in health surveillance. Calls for heat- and sun-stroke are now routinely monitored as part of the UK Heat-wave plan.

Original languageEnglish
Pages (from-to)194-201
Number of pages8
JournalSozial- und Praventivmedizin
Issue number4
Publication statusPublished - Nov 2006

Bibliographical note

Funding Information:
SH and RSK were funded by the European Commission DG SANCO as part of the EUROHEAT project on improving public health responses to heat wave in Europe (Agreement – 2004322). GSL and GS are employed by the Health Protection Agency, and DC is also employed by the Health Protection Agency but his post is funded by NHS Direct. EG is employed by NHS Direct.


  • Heat-waves
  • NHS Direct
  • Primary care
  • Surveillance
  • Temperature


Dive into the research topics of 'Syndromic surveillance use to detect the early effects of heat-waves: An analysis of NHS direct data in England'. Together they form a unique fingerprint.

Cite this