Americans are being urged to get vaccinated against the flu as health officials reported an early rise in seasonal influenza activity, with hospitalizations, positive test results and emergency department visits increasing in recent weeks.
The Centers for Disease Control (CDC) reported 4,811 laboratory-confirmed flu hospital admissions nationwide during the week ending October 17, while its surveillance network recorded the highest hospitalization rate for this point in the season since 2010-11.
"Early-season influenza activity is currently higher than typically observed at this time of year," the CDC said in its latest weekly surveillance report.
Newsweek reached out to the CDC via email Saturday for comment.
Separate data from Walgreens suggest flu season may be arriving earlier than normal. The pharmacy chain said in a statement this week flu activity is tracking roughly four weeks ahead of recent seasons based on testing, prescription and retail sales data.
"It’s an early start to the season, and, when it comes to the primary value of the vaccine, it is in prevention of severe disease including hospitalization. It’s too early to know the trajectory of the season, but people should get vaccinated ASAP," Dr. Amesh A. Adalja, a senior scholar at Johns Hopkins Center for Health Security, told Newsweek.
...
Which Flu Virus Is Spreading?
Nearly all of the flu viruses identified so far this season have been H1N1. While the virus has undergone genetic changes over time, the CDC says it is not a newly emerged strain and remains a descendant of the H1N1 virus responsible for the 2009 swine flu pandemic.CDC laboratory surveillance showed that 239 of 241 influenza A samples analyzed during the week ending October 17 were H1N1, indicating that the virus is overwhelmingly dominant in circulation this season. They are not detecting the H3N2 subclade K, or so-called super flu, that surfaced last year.
Researchers are continuing to study how the currently circulating viruses are evolving and whether those changes could have implications later in the season. Health officials say it is still too early to determine whether this season will ultimately prove more severe than recent years.
Map Shows Where Flu Activity Is Rising
The latest CDC map shows varying levels of influenza activity across states for the week ending October 17, with health officials continuing to monitor where transmission is accelerating fastest as colder weather approaches.
The CDC's map measures flu-like illness rather than confirmed flu cases, meaning it captures people seeking medical care for symptoms consistent with influenza, including fever, cough and sore throat.
Louisiana and Hawaii reported "moderate" levels of influenza-like illness during this span. Florida, South Carolina, West Virginia, Oregon and Washington have reached a "low" activity level, while the other states remain at the minimal level.
Why This Flu Season Is Starting Early
While there aren't high concentrations of cases yet, the unusually high number of hospitalizations worries some health experts.
They caution that flu seasons can vary significantly from year to year -- some begin slowly before accelerating later in winter, while others start earlier and spread more quickly.
The agency emphasized that it is still too early to determine how severe the season may ultimately become. However, the upward trend in hospitalizations and other indicators has drawn attention, as activity is already running above historical expectations at this point in the season.
Should You Get a Flu Shot Now?
The CDC continues to recommend annual influenza vaccination for everyone 6 months and older.
According to the agency, flu vaccines are widely available, and September and October remain the preferred months for most people to get vaccinated before activity peaks during the winter.
Health officials say it is too early to know whether the genetic changes being observed in current H1N1 viruses will have any impact on vaccine effectiveness. The CDC notes that surveillance is ongoing and that experts are still evaluating which viruses may predominate as the season progresses.
For now, federal health officials continue to stress that vaccination remains the best available tool for reducing the risk of severe illness, hospitalization and death from influenza.
What Happens Next?
Flu activity typically continues increasing through late fall before reaching its seasonal peak during the winter months.
The next several weeks will help determine whether the current rise represents the start of an unusually early flu season or a temporary increase in activity. Health officials will be watching hospitalization trends, regional spread and the continued dominance of H1N1 as more surveillance data become available.
Patients who experience fever, cough, sore throat, runny nose, headaches, muscle aches or fatigue should seek medical treatment.
Newsweek’s reporters and editors used Martyn, our AI assistant, to produce this story.