Validity of International Health Regulations in Reporting Emerging Infectious Diseases

Michael Edelstein

, David L. Heymann, Johan Giesecke, and Julius Weinberg

Author affiliations: London School of Hygiene and Tropical Medicine, London, UK (M. Edelstein, D.L. Heymann); Chatham House, London (D.L. Heymann); European Centre for Disease Control, Stockholm, Sweden (J. Giesecke); and Kingston University, London (J. Weinberg)

Abstract

Understanding which emerging infectious diseases are of international public health concern is vital. The International Health Regulations include a decision instrument to help countries determine which public health events are of international concern and require reporting to the World Health Organization (WHO) on the basis of seriousness, unusualness, international spread and trade, or need for travel restrictions. This study examined the validity of the International Health Regulations decision instrument in reporting emerging infectious disease to WHO by calculating its sensitivity, specificity, and positive predictive value. It found a sensitivity of 95.6%, a specificity of 38%, and a positive predictive value of 35.5%. These findings are acceptable if the notification volume to WHO remains low. Validity could be improved by setting more prescriptive criteria of seriousness and unusualness and training persons responsible for notification. However, the criteria should be balanced with the need for the instrument to adapt to future unknown threats.

The great influenza pandemic of 1918 and the increase in HIV/AIDS are 2 striking examples of the devastation and profound effect on human societies caused by emerging infectious diseases (EIDs) (1). The Institute of Medicine defines EIDs as “new, re-emerging, or drug-resistant infections whose incidence in humans has increased or whose incidence threatens to increase in the near future” (2). EIDs are a global phenomenon, with hotspots from which EIDs are more likely to appear, concentrated in low-latitude developing countries (3). EIDs are probably underreported, particularly in areas which have hotspots and also weak surveillance systems (4). A study in 2008 by Jones et al. reported 335 EIDs during 1940–2004 (3).
The purpose of the 2005 International Health Regulations (IHR) is to “help the international community prevent and respond to acute public health risks that have the potential to cross borders and threaten people worldwide” (5). This purpose includes development of an international reporting system, under which member states have a duty to report to the World Health Organization (WHO) “all events which may constitute a public health emergency of international concern” (5). These events are not limited to communicable diseases and can include contaminated food, chemical contamination of products or the environment, release of radionuclear material, or other toxic release (6). Events are reported to WHO by designated national focal points (NFPs) in each member state. WHO has designed a decision instrument contained in Annex 2 of the 2005 IHR (7) to assist with the notification process on the basis of an algorithm comprising 4 main criteria: the event has a serious public health effect, the event is unusual or unexpected, there is a major risk for international spread, and there is a major risk for international travel or trade restrictions. At least 2 of the criteria must be satisfied for an event to be notifiable.
An IHR expert committee suggested regular evaluations of the notification process (8). However, the only published evaluation of the Annex 2 decision instrument is a reliability study that analyzed NFPs notification concordance (9). This study also reported a sensitivity of 80% (on the basis of 5 events) and a specificity of 50% (on the basis of 4 events). Although the study reported a high reliability, the number of events was too low to adequately assess the sensitivity and specificity of the decision instrument. A 2008 WHO technical report on Annex 2 (10) mentions a 2006 workshop assessing the decision instrument validity and finding a sensitivity of 100% and a specificity of 55% on the basis of 10 events. There were no details on the methods used and the study results were not published.
The aim of this study was to evaluate the predictive validity of the Annex 2 decision instrument. We focused on EIDs by applying screening test evaluation methods to the IHR Annex 2 decision instrument and estimated its sensitivity, specificity, and positive predictive value (PPV).

Validity of International Health Regulations in Reporting Emerging Infectious Diseases - Vol. 18 No. 7 - July 2012 - Emerging Infectious Disease journal - CDC