GENEVA, Feb. 13 (Xinhua) -- Influenza activity remains high in the temperate zone of the northern hemisphere, with a few countries reaching levels exceeding those of previous years, the World Health Organization (WHO) warned on Tuesday, adding that the best prevention remains vaccination.

Though most countries currently experiencing the influenza season have reported influenza-like illness reaching moderate levels in comparison with previous years, some, however, have reported levels of hospitalization and ICU admissions reaching or exceeding peak levels compared to previous influenza seasons, WHO said.

The UN health agency recommends countries with current influenza activity or entering their season to adopt necessary measures for ensuring appropriate case management, compliance with infection control measures and seasonal influenza vaccination for high risk groups.

In Europe, influenza activity remains high in most countries, especially in Northern and Southwestern Europe. It has peaked in a few countries and started to increase in Eastern Europe.

As the WHO estimates that yearly annual influenza epidemics will result in up to 650,000 respiratory deaths, the best prevention, it recommends, remains vaccination.

Meanwhile, WHO recommends annual vaccination for pregnant women at any stage of pregnancy, children aged between six months to five years, elderly individuals aged more than 65 years, individuals with chronic medical conditions and health care workers.