International surveillance with the new International Health Regulations

  Published: 30.01.08 Updated: 30.01.2008 15:42:48

Preben Aavitsland

Norwegian Institute of Public Health, Oslo, Norway

The new International Health Regulations (IHR) (1) entered into force on June 15, 2007. The IHR are a) a legal framework for surveillance of international health threats, b) a procedure for WHO’s recommendations to counteract public health emergencies of international concern, and c) a set of rules concerning routine measures against international disease spread. Here, I will briefly review the first of these features.

Surveillance and epidemic intelligence

Surveillance has two possible main objectives. Firstly, surveillance may be performed in order to measure the distribution of cases of disease by time, place and person. The emphasis is on medium- and long-term change. The purpose may be to identify population groups at higher risk for disease or to relate time trends to shifts in risk factors or prevention efforts. Secondly, surveillance may be conducted in order to detect sudden changes in numbers of cases, indicating clusters or outbreaks, or to detect events directly. In the latter meaning surveillance is part of ”epidemic intelligence”. This concept has been defined as ”all the activities related to early identification of potential health threats, their verification, assessment and investigation in order to recommend public health measures to control them” (2).

Event based surveillance

The new IHR introduce a global epidemic intelligence system. The purpose is to inform WHO about all events that may pose international public health risk. WHO will then assess all events and may decide to inform other countries according to the strict procedures set forth in Article 11 of the IHR. WHO may also declare a so-called ”public health emergency of international concern” and then give recommendations to counteract the emergency.

The events of interest may be, for instance,  clusters of cases, verified outbreaks or epidemics, single cases, contamination of food, or chemical, nuclear or radiological releases. The change from the previous IHR disease list (that included only yellow fever, plague and cholera) to a new paradigm of event reporting is rational and sensible for several reasons:

Firstly, the potential public health risk from a case of a given disease depends not only on the epidemiological characteristics of the disease (infectiousness, transmission routes, etc.) but also on the circumstances. For instance, a case of cholera in Stockholm is no public health risk while a case of cholera in a flood-stricken village in Bangladesh may lead to a disaster. Thus, it is the event (disease + circumstances) that is notifiable, which allows for a more informed judgement of reporting, and not only an automatic adherence to a list of diseases.

Secondly, notification might be delayed for weeks if it is necessary to wait for confirmation of a diagnosis. With the new IHR, an event must be notified even if the diagnosis is not known yet.

Thirdly, a new, previously unknown disease cannot be on a disease list. SARS could not be on any disease list when it emerged because it was previously an unknown disease. Regardless, SARS posed a major public health threat. Thus, under the new IHR an event involving cases of a new disease similar to SARS must be notified.

When to contact WHO?

The IHR specify the criteria for contacting WHO (table 1). Contacting WHO initiates a dialogue between the country and WHO with the purpose of achieving a consensus on the assessment of the event, including the need for informing other countries and for declaring a ”public health emergency of international concern”. Given this dialogue approach, it becomes clear that countries should contact WHO early and often.

Table 1. Types of contact between countries and WHO regarding epidemic intelligence under the IHR

Type of contact

Reference to IHR

Contact initiated by

Criteria for and contents of contact


Article 8


Voluntary consultation regarding events that are not notifiable according to Article 6. These may be events for which there is insufficient information available to answer the four questions in Annex 2.


Article 6 and Annex 2


Mandatory notification of all events which may constitute a public health emergency of international concern according to Annex 2 (see table 2).


Article 9.2


Mandatory information about public health risk identified outside the country, as manifested by exported or imported human cases, vectors or goods.

Verification (or refutation)

Articles 9.1 and 10


Mandatory response to WHO’s request for verification (or refutation) regarding events that WHO knows about from other sources than notifications or consultations.

The main type of contact is notification. Annex 2 of the IHR (1) gives detailed guidance concerning the events that should be reported. Briefly, all national events must be assessed using four main questions and eleven sub-questions. If the answer is ‘yes’ to two or more of the four main questions, the event must be notified (table 2). If the answer is ‘yes’ to only one question or if there is any doubt about the answers, it is nevertheless wise, but not required, to report the event.

Table 2. Decision instrument for assessing whether to notify events to WHO under Article 6 of the IHR. This is a simplification of the original version in Annex 2 of the IHR (1).






Any event of potential international public health concern.



1. Is the public health impact of the event serious?


2. Is the event unusual or unexpected?


3. Is there a significant risk of international spread?


4. Is there a significant risk of international travel and trade restrictions?


If two or more yes 


























Notify to WHO

Event involving cholera, pneumonic plague, yellow fever, viral haemorrhagic fevers (Ebola, Lassa, Marburg), West Nile fever or other diseases that are of special national or regional concern, e.g. dengue fever, Rift Valley fever, and meningococcal disease.



A case of smallpox, poliomyelitis due to wild-type poliovirus, human influenza caused by a new subtype or severe acute respiratory syndrome (SARS).



A case is unusual or unexpected and may have serious public health impact. Thus, answers to two of the questions are by default ‘yes’. Thus, the event must always be notified.














Notify to WHO

How to contact WHO?

Contacting WHO under the IHR is very simple. For the European Region, the WHO has designated a WHO IHR Contact Point in the Regional Office in Copenhagen and informed countries of the contact details. The most convenient way to inform WHO is by sending an e-mail. Note that official communication to WHO regarding IHR matters (table 1) must come from the National IHR Focal Point in each country.

Contents of contact with WHO

Given that the purpose of the dialogue with WHO is to assess the event, including the need for informing other countries and for declaring a ”public health emergency of international concern”, the country must provide the information that WHO needs for that assessment. This may include a detailed description of the event (including case definitions, laboratory results, source and type of the risk, number of cases and deaths and conditions affecting the spread of the disease), the health measures employed and any difficulties faced or support needed in responding to the event.

As the event unfolds, more information will become available. The dialogue with WHO should include this new information in accordance with Article 6.2.


WHO’s epidemic intelligence with the IHR will be successful only with the collaboration of all countries. National capacities must be developed quickly to detect events, contact must be made with WHO as early as possible regarding events, and information must not be withheld. Countries should consider IHR to be a positive initiative that will serve national and international communities at large.

In Northern Europe, the EpiNorth project and journal have worked according to this principle for many years. Indeed, the categorical imperative of the great Northern European philosopher Immanuel Kant, born in Königsberg (today Kaliningrad), may also apply to international surveillance: ”Act only according to that maxim whereby you can at the same time will that it should become a universal law.” (3) In other words: notify WHO of the events in your country that you would want to know about if they had occurred in another country.


  1. International Health Regulations (2005). Geneva: World Health Organization, 2005. (
  2. Kaiser R, Coulombier D, Baldari M, Morgan D, Paquet C. What is epidemic intelligence, and how is it being improved in Europe? EpiNorth 2006; 7: 8-10.
  3. Kant I. Grundlegung zur Metaphysik der Sitten. Köningsberg: 1785