Flu activity shows signs of receding in Europe

Feb 21, 2011 (CIDRAP News) – Influenza activity persists at medium to high levels in most European Union countries but is showing signs of decreasing, according to the latest report from the European Centre for Disease Prevention and Control (ECDC).

Fourteen countries reported a decrease in influenza-like illness (ILI) and acute respiratory infections (ARI) in the week of Feb 7 to 13, which was 10 more than did so the previous week, the ECDC said. The proportion of respiratory samples from sentinel healthcare providers dropped to 43%, compared with a peak of 57% in the last week of 2010.

However, Greece, Hungary, Italy, and Sweden reported high-intensity flu activity, and Luxembourg had very high activity, the ECDC said. Cases were reported at medium levels in 19 countries and Scotland. The rest of the United Kingdom had low activity, as did Cyprus and Malta.

As for the geographic pattern, 18 countries around Europe reported widespread flu, while six countries had regional activity, the agency reported. Activity shrank from widespread to regional in Germany and from local to sporadic in England. But in Iceland, the epidemic reached regional status for the first time this season.

Just four countries (Austria, Czech Republic, Iceland, and Slovakia) reported that flu activity was increasing, while 10 said it was unchanged.

The 2009 H1N1 virus continued to dominate the European flu landscape overall, as it has throughout the season, the ECDC said. Of 4,980 flu viruses detected during the week, 67% were type A and 33% were type B. Among 2,821 influenza A viruses that were subtyped, 99.2% were 2009 H1N1, and the rest were H3.

Influenza B was the dominant flu type in Ireland, the Netherlands, Norway, Spain, Sweden, and the United Kingdom. The circulating viruses continued to be well matched to the seasonal flu vaccine, the agency said.

Viral resistance to neuraminidase inhibitors has remained uncommon, the report said. Of 738 2009 H1N1 isolates tested so far this season, 28 (3.8%) were resistant to oseltamivir (Tamiflu) but sensitive to zanamivir (Relenza). Eight of the resistant viruses were from patients who had not been treated with oseltamivir, out of 24 patients whose treatment status was known.

An ECDC chart shows that severe acute respiratory infection cases from all causes peaked in the last week of 2010 and have declined steadily since then, except for an uptick in the third week of January.

In notes on hospital case in individual countries, the report says Denmark had 33 flu patients in intensive care units (ICUs) on Feb 14, accounting for 9.6% of ICU patients in the country. In the United Kingdom the number of flu patients in critical care beds dropped to about 70 last week, compared with a peak of nearly 800 earlier in the season.

The report also notes that a single case of co-infection with influenza B and 2009 H1N1 was detected in Greece.

See also:

Feb 18 ECDC flu report

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