WSU Virology

The CDC’s current estimates aren’t all that current.

the numbers can tell us only how many people were suffering from the flu a couple weeks ago.

scans millions of Google searches from around the world to track flu activity in near real time.

CDC outpatient surveillance figure of an unprecedented 8.9 percent.

“Is it going to be a more severe season than last year? I think without question,” Jhung said. “Is it going to be a more severe season than a couple years ago, or the previous 10 years? We don’t know, and won’t know until the end of the season.”

the dominant strain so far this year is H3N2, not the novel “swine flu” strain of H1N1 that spooked the world.

the figure to which Google Flu Trends corresponds is the one that tells us what percentage of outpatient doctor visits are flu-related at the institutions in the CDC’s reporting network. But a separate PLOS One study from 2011 found that it doesn’t correlate quite as well with another CDC metric that’s based on the number of laboratory-confirmed cases of the flu.

“Think about that,” Dr. Osterholm said. “Even though they were old, they were still protected. We’ve got to figure out how to capture that kind of immunity — which current vaccines do not.”

Dr. Bresee acknowledged the difficulties, saying: “If I had the perfect answer as to how to make a better flu vaccine, I’d probably get a Nobel Prize.”

a preliminary study rated this year’s vaccine as 62 percent effective, even though it is a good match for the most worrisome virus circulating.

urged Americans to keep getting flu shots.

Even though deaths stepped — barely — into epidemic territory for the first time last Saturday, the C.D.C. officials expressed no alarm, and said it was possible that new flu infections were peaking in some parts of the country.

Epidemiologists count how many death certificates are filed in a flu year, compare the number with normal years, and estimate what percentage were probably flu-related.

The C.D.C.’s vaccine effectiveness study bore out the point of view of a report released last year by the University of Minnesota’s Center for Infectious Disease Research and Policy. It said that the shot’s effectiveness had been “overpromoted and overhyped,” said Michael T. Osterholm, the center’s director.

At the same time, he praised the C.D.C. for measuring vaccine effectiveness in midseason. “We’re the only ones in the world who have data like that,” he said.

“To get a vaccine across the ‘Valley of Death’ is likely to cost $1 billion,”

the metric means the shot “reduces by 62 percent your chance of getting a flu so bad that you have to go to a doctor or hospital.”

“far from perfect, but by far the best tool we have to prevent influenza.”

Most vaccinations given in childhood for threats like measles and diphtheria are 90 percent effective or better. But flu viruses mutate so fast that they must be remade annually.