Widespread Influenza Activity Now Reported in 21 States

The number of states with widespread influenza activity this winter is continually rising, as the 2016-2017 flu season continues to be dominated by the H3N2 strain of the influenza A virus, leading to more severe illnesses.

According to the Centers for Disease Control and Prevention’s (CDC) weekly FluView report, 21 states are now reporting widespread flu activity, which is up from the previous week’s report that had noted only 12 states with widespread influenza. The CDC measures flu activity by geographic spread as either sporadic, local, regional, or widespread. In the United States, Region 9— which includes Arizona, California, Guam, Hawaii, and Nevada– has been hit the hardest so far this season and has reported the highest number of flu cases of all the country’s surveillance regions. Meanwhile, parts of the Northeast and Midwest also continue to see an increase in influenza outbreaks.

Exacerbating this winter’s flu season is the prevalence of the influenza A (H3N2) strain, which is causing more severe illnesses throughout the United States. The recent FluView report noted that, of the 6,016 collected specimens that tested positive for influenza in public health laboratories around the country, more than 92% were influenza A; 5,261 were subtyped through antigenic characterization as the more virulent H3 strain. Influenza B strains made up 7.4% of all specimens that were identified in laboratory surveillance. Despite the strong match between this season’s influenza vaccine and the strains currently circulating, only about 45% of Americans receive a flu shot each season, which leaves more than half of the population at greater risk of getting sick with the flu.

In Pennsylvania, one of the 21 states where influenza activity is now widespread, there has been at least 10,766 confirmed flu cases, with the southwest region of the state seeing the most flu activity. In Allegheny County, the state’s Department of Health surveillance laboratories have confirmed at least 1,505 influenza-positive case, with more than 84% of these cases caused by influenza A (H3N2). To date, there have been 14 influenza-associated deaths in Pennsylvania this flu season, 12 of which occurred in adults aged 65 years or older, with no reported pediatric deaths. In Erie County, the number of flu cases reported in the first week of 2017 doubled from the previous week’s number of cases, as local health officials remind area residents that they still have time to receive the flu shot and protect themselves from the virus.

In the Region 6 state of Oklahoma, also hit by widespread flu activity, 54 individuals were either hospitalized or died due to influenza infection from January 4 to January 10, bringing the total number of flu-associated deaths this season to 5 and the total number of hospitalizations to 226. Of those deaths, 4 occurred in individuals aged 65 years or older. Oklahoma State Department of Health officials have not released details about the fifth death, which occurred in a child between the ages of 5 and 17.

Oregon, hard hit by both severe winter weather and influenza activity this season, has seen a high percentage of positive flu tests in recent weeks. In the first week of January, the Oregon Health Authority reported 172 flu-related hospitalizations due to at least 21 outbreaks across the state. Along with encouraging residents to receive flu vaccination, state health officials are reminding individuals that they can avoid falling ill this season by washing their hands often, taking precautions to avoid the spread of germs, and quitting smoking, as individuals who smoke are known to catch the flu more easily.

Due to healthcare advancements made in the last few decades, influenza is seemingly harmless. However, in those most susceptible to complications, a flu infection may pose a more serious problem, and an infection can be life-threatening. As Tom Frieden, MD, MPH, may soon be leaving his position as director of the CDC, he recently told the Washington Post in an interview that an influenza pandemic is his biggest concern for the nation’s health. “Even in a moderate flu year, [influenza] kills tens of thousands of Americans and sends hundreds of thousands to the hospital. That increase in mortality last year may have been driven in significant part by a worse flu season compared to a mild flu season the prior year,” said Dr. Friedan. “So flu, even in an average year, really causes a huge problem.”