The flu epidemic intensified a few week ago, but it continued to worsen with widespread outbreaks being reported in every state except Florida. NBC's Robert Bazell reports.

And there's new information tonight about this year's flu epidemic and why it has suddenly gone from bad to worse as all too many people know firsthand. The story from our chief science correspondent, Robert Bazell.

The epidemic intensified only a few weeks ago, but it keeps getting worse. Today's report shows wide spread outbreaks in every state except Florida. The percentage of deaths from respiratory illness, an indication of flu activity, has been climbing sharply, and so is the number of visits to doctors and hospitals for people with flu-like illness. So the CDC has no trouble saying there is a bad epidemic right now.

We really don't know when the season will peak, and when it will be over with.

Kara Conway, 11-years-old, and Amanda Ell is 12, are 2 of 22 children known to have died from the flu this season. The CDC carefully tracks pediatric deaths, and added 10 more this week alone. The tragic childhood cases are relatively rare. The influenza kills tens of thousands of mostly older people every year. 5 died this week in this Salt Lake City Nursing Home. The big danger now is a strain called Brisbane 10, it popped up in the US earlier this month. It makes people very sick and this year's flu shot which must be made up a year in advance does not protect against it.

The Brisbane 10 strain really wasn't on our radar screen when we made the vaccine strain selection decision last year in February.

Just yesterday, officials decided to include it in next year's vaccine, and they can only hope that yet another entirely new strain will not appear in the meantime.

No one knows why new strains suddenly appear as this one did, but the population of the world is so big, and with the huge amount of international travel, certainly any new strain that appears anywhere can immediately become a threat everywhere else, William.

Such a lottery out there, Robert Bazell, Thanks for that.