H1N1 seen lying low, then rising again in Europe

LONDON (Reuters) - Europe is unlikely to see another wave of pandemic H1N1 flu soon but local epidemics are likely as winter returns to the Northern hemisphere, health officials said on Monday.

The European Center for Disease Prevention and Control (ECDC) said the H1N1 swine flu virus would probably spread at low levels during 2010's spring and summer, and be the dominant and threatening strain in the winter flu season.

"It seems unlikely that there will be another spring/summer pandemic wave in Europe unless there are significant unrecognized uninfected populations or the virus changes and becomes more transmissible," the ECDC, which monitors disease in the European Union, said in its latest flu risk assessment.

The World Health Organization (WHO) declared last June that H1N1 was causing a pandemic -- the first influenza pandemic in 40 years -- after it was discovered in Mexico and the United States and spread around the world within six weeks.

So far the WHO has confirmed 16,226 deaths from the H1N1 pandemic virus, but the real death toll -- which will take at least a year to ascertain -- will be far higher, as most victims will have never been diagnosed or tested.

WHO said last month it was too early to say the pandemic had peaked, but it will review a decision on whether to declare a "post peak" phase in a few weeks' time.

Because evidence so far suggests there have been no major changes in the H1N1 virus, the Stockholm-based ECDC said similar death rates should be expected in the 2010/2011 winter, but "numbers of cases will be considerably smaller because of the previous transmission and vaccination."

"ECDC's advice to EU citizens remains to accept influenza vaccination when it is offered to them," it said.

The WHO says more than 300 million people have been vaccinated against pandemic flu, and the immunizations, which have an excellent safety record, are 70-75 percent effective.

The pandemic sparked a race to develop new vaccines by drugmakers such as GlaxoSmithKline and Sanofi-Aventis but many people declined the offer of the vaccine when the flu outbreak turned out to be milder than feared.

(Editing by Janet Lawrence)