Rising flu activity in temperate Northern Hemisphere countries, especially in North America, Europe, and Central Asia, has led to a rise in global flu detections, the World Health Organization (WHO) said yesterday in an update that covers roughly the middle 2 weeks of December.

In North America, flu is high or very high across most of the United States, and Canada's activity is at expected levels for this time of year. For the week ending December 31, activity in Europe and Central Asia was up sharply over the epidemic threshold. For example, Russia reported very high flu activity, with Greece and Luxembourg reporting high levels.
East Asia's activity remained elevated, mainly due to activity in China and South Korea. Elsewhere, Algeria reported an increase in flu detections, as did Lebanon. In Oceania, Australia's flu activity remained low overall, but with small increases reported in some states. And in temperate South America, flu was above the seasonal threshold in Chile.
Globally, of respiratory samples that were positive for flu at national flu labs in the middle of December, 86.6% were influenza A, and, of subtyped samples, 72.7% were the H3N2 strain.