Updated guidance on novel coronavirus by WHO: surveillance, applied epidemiological studies and clinical guidance
The WHO has recently updated a number of its interim guidance documents for the novel coronavirus including clinical management (11th February) and the case definition for reporting (19th February);
the most recent development is a revision of WHO’s interim guidance on surveillance (March 18th) (1) which replaces the guidance of late November 2012 (2):
- Interim Guidance - Clinical management of severe acute respiratory infections when novel coronavirus is suspected: What to do and what not to do - 11 February 2013
- Revised interim case definition for reporting to WHO – novel coronavirus - 19th February 2013
- Interim surveillance recommendations for human infection with novel coronavirus - 18 March 2013
The new surveillance guidance is a more comprehensive document and contains a table of investigations and studies that WHO and those advising it (including ECDC) agreed should be carried out where possible. A number of these studies are briefly mentioned in the recommendations of ECDC’s February Risk Assessment.(3)
There are some changes in WHO’s surveillance guidance starting with an explicit statement on the two objectives of the surveillance:
- to detect early, sustained human-to-human transmission,
- to determine the geographic risk area for infection with the virus.
In the March guidance WHO recommends testing for novel coronavirus of persons in clusters of acute respiratory infection requiring hospitalisation (including health care workers) or where the respiratory infection is unexpectedly severe. It notes that novel coronavirus should be considered even where there is another infection if that other diagnosis does not explain the severe clinical course.(1) This latter point stems from the recent European cluster where the imported index case was positive for an influenza A virus but then did very poorly and was found to also have the novel coronavirus infection.(4) WHO also recommends testing persons with a respiratory infection who have been in contact with a confirmed or a probable case in the preceding 10 days irrespective of the severity of the infection.
In addition WHO makes new recommendations for countries where the novel coronavirus has already been detected, emphasising the testing of patients with infections that are severe enough to require mechanical ventilation. However WHO does not now distinguish between countries where infections are appearing as unexplained sporadic cases and countries, such as in Europe, where all the infections to date can be accounted for by imported infections or infections in-country linked to imported cases.
ECDC Comment (27-03-2013)
Comparing the new and old guidance from WHO it is apparent that one recommendation for testing has changed. The recommendation of prioritizing testing patients with severe respiratory infection who have recently been in a country where there have been sporadic cases appearing without an identified source of infection is no longer included.(1,2) In the November WHO guidance there was specific reference to countries in the Arabian Peninsula and neighboring countries.(1) The current ECDC and CDC guidance retains this recommendation.(3,5) The CDC guidance also lists the countries and this guidance is echoed in the recommendations of a number of European countries such as France, Germany and the United Kingdom.
In ECDC’s view, at present there is not a case for considering European countries epidemiologically the same as those countries in the Middle East where indigenous sporadic infections and clusters have been detected. Europe has to date had three imported cases of severe respiratory infection confirmed as due to the novel coronavirus where the infection was probably acquired in Arabian Peninsula countries.(3,6) One of these imported infections led to two secondary infections acquired in Europe. One of these secondary infections had a lethal outcome and the other a mild outcome.(4) Extensive case-contact investigations have not so far revealed on-going transmission or transmission in the European countries.(4,7,8) No other infections have come to light in Europe despite considerable testing for novel coronavirus.(9) Hence with these present data there is a strong case for EU countries retaining the current ECDC recommendation on geography as one risk factor when selecting patients for testing, that is, testing for novel-CoV in patients developing severe acute respiratory infection after being in the Arabian Peninsula and neighboring countries within ten days of onset of symptoms.(3) Similarly there remains a strong case that health professionals engaged in receiving evacuated patients from the Arabian Peninsula and neighboring countries with any infectious respiratory condition should be vigilant concerning the possibility of infection with novel-CoV.(3) These recommendations are similar to the United States.(5)
At the same time most other WHO recommendations for testing remain unchanged and are applicable to Europe, namely:
- identifying and testing contacts of confirmed cases irrespective of their clinical status [the HPA report contains a workable definition of close contacts (4)]
- considering novel coronavirus infection in clusters of severe acute respiratory infection, in health care workers caring for persons with severe respiratory illness and, resources permitting, in persons with unusually severe and progressive acute respiratory infections despite appropriate treatment.
ECDC continues to endorse these recommendations that are applicable irrespective of travel history.
As the WHO and ECDC documents as well as a Lancet commentary note, there is still a lot to learn about these infections.(1,3,10) Hence there is a vital need to quickly undertake applied epidemiological studies such as those recommended by WHO and ECDC in a number of countries including in Europe, where resources allow. (1,3) Then further potential recommendations on testing can be made from a more complete evidence base.
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