There’s been little relief from the flu in the past week, with influenza activity remaining elevated in most parts of the United States.
Forty-seven states reported widespread influenza activity during the week of Dec. 30-Jan. 5, according to the latest data from the Centers for Disease Control and Prevention. The only parts of the country that aren’t reporting elevated levels of activity currently are in the West, though the flu may be headed in that direction soon, health officials said.
Dr. Thomas Frieden, director of the CDC, predicted that the high levels of influenza activity would likely continue for several more weeks, based on historic trends, but nothing is certain.
"But as we often say, the only thing predictable about flu is that it’s unpredictable," he said in a press conference on Jan. 11. "Only time will tell us how long our season will last and how moderate or how severe this season will be in the end."
Outpatient visits for influenza-like illness made up about 4.3% of patient visits during the first week of 2013, which is above the national baseline of 2.2%. Influenza also was associated with two more deaths among children, bringing the total number of pediatric deaths to 20 for this influenza season. One death, associated with influenza A (H3) virus, occurred during the week ending on Dec. 29, 2012, but was not reported until the next week. The second death, which occurred during the week ending Jan. 5, was associated with influenza A, but the subtype was not determined.
Since the start of the 2012-13 flu season, influenza A viruses have been the most common, followed by influenza B viruses. The H1N1 virus has been rare this year, according to the CDC data.
Because of the early onset of this year’s influenza season, the CDC also got an earlier-than-usual look at the effectiveness of the vaccine. Preliminary data show that this year’s vaccine is 62% effective overall. That means that if a person is vaccinated, they are about 62% less likely to have to see a physician to treat their illness, Dr. Frieden said. The vaccine effectiveness figure is based on early data from 1,155 children and adults with acute respiratory infection from Dec. 3, 2012 to Jan. 2, 2013 (MMWR 2013;62[early release]:1-4).
Despite the "moderate" effectiveness of the vaccine, Dr. Frieden still urged Americans to get vaccinated, if they haven’t already. "The flu vaccine is far from perfect, but it’s still by far the best tool we have to prevent the flu," he said.