Eurosurveillance - Volume 8, Issue 12, 01 December 2003

In this issue, Radun et al report a retrospective investigation of SARS in 21 German guests who stayed at Hotel 'M' in Hong Kong between 21 February and 3 March 2003 (1). They were able to identify retrospectively an unrecognized case of SARS in a patient who stayed on the ninth floor on the night of 21-22 February (the same floor as the symptomatic physician who had acquired SARS in Guangdong province, China).

Hong Kong played a pivotal role in the international spread of the Severe Acute Respiratory Syndrome (SARS): a doctor who spent the night of 21-22 February 2003 at Hotel 'M' was identified as the index case for four national and international clusters of SARS. In parallel to the international collaborative study led by WHO and United States, a retrospective study on the cohort of German persons staying at Hotel 'M' was conducted. The inclusion criteria covered a period from 21 February to 3 March 2003 to allow the detection of cases possibly due to environmental contamination. In the twenty-one German guests traced as having stayed at Hotel "M" during this period, one case of laboratory confirmed SARS was found. The case history suggests that close vicinity to the index patient may have played a role in transmission. In line with findings of environmental investigations in the hotel, environmental contamination should be considered as a possible source of infection.

Influenza activity varied across Europe during the 2002-2003 season both in terms of the intensity of clinical activity and the circulating virus types/subtypes. Influenza B was generally predominant in the 'western' parts of Europe (Portugal, Spain, the United Kingdom and Ireland) and influenza A (H3N2) in the 'central' and 'eastern´ areas (Germany, Italy, Denmark, Switzerland, Poland, Slovenia, the Slovak Republic, the Netherlands). A number of countries experienced mixed seasons, first experiencing activity associated with influenza B and then with influenza A (Belgium, France and Spain). Generally, countries where influenza B was predominant had low (compared to historical data) levels of intensity (a mild season) and longer periods of influenza activity compared to countries where influenza A (H3N2) was predominant. A number of countries, all where influenza A (H3N2) was predominant, reported high levels of intensity compared to historical data: the Czech Republic, Denmark, Germany and Poland. In the six countries where age-specific incidence rates were available, the highest rates were observed among those aged 0-14 years. The influenza virus strains circulating in Europe had a good match with the virus strains in the influenza vaccine. A small number of isolates (A/Fujian/411/2002 (H3N2)-like) were reported at the end of the season that had a reduced reactivity to anti-sera of the vaccine strain. The composition of the 2003-2004 influenza vaccine is the same as during the 2002-2003 season.

Surveillance requires time for analysis and for the communication to physicians. In order to reduce this delay, a new surveillance system based on the use of a near patient test (NPT) has been evaluated. The high specificity of NPT together with the rapidity in obtaining the results, make these tests attractive for surveillance of influenza epidemic in community practice. Such surveillance has been used in several countries including Switzerland. Four different seasons - between 1999 and 2003 - of this type of surveillance experienced in Switzerland have been analysed. The heterogeneity in terms of intensity and type of strains detected during these four epidemics seasons allowed an efficient evaluation. The average gain of time with NPT compared to cell culture was nine days. Furthermore, training of participants appeared to be essential to assure the quality of the surveillance system. A statement on the use of NPTs for influenza surveillance has finally been endorsed by EISS members. Included are recommendations that the network should use the NPTs data, which provides additional information to the classical surveillance systems, as an "early warning" system of a change in influenza activity.