CDC: Influenza season officially underway

ATLANTA — The influenza season is officially underway as flu incidence is already above the national threshold, Thomas Frieden, director of the Centers for Disease Control and Prevention, told reporters during a teleconference Monday. "This is the earliest regular flu season we've had in nearly a decade, since the 2003-2004 flu season," he said. "That was an early and severe flu year, and while flu is always unpredictable, the early nature of the cases as well as the specific strains we're seeing suggest that this could be a bad flu year."

Influenza-like illness activity is particularly strong across five states in the southeastern and south central regions, including Alabama, Louisiana, Mississippi, Tennessee and Texas. Moderate levels of illness activity have been reported in Georgia and Missouri. 

One of the predominant strains includes an H3N2 influenza A, Frieden noted. "What we've seen in past years is that H3 predominant years tend to be the worst years."

However, those who have had their flu shots should be well-protected, Frieden added. Out of the flu strains that have been submitted to the CDC so far this season, about 90% are well-matched to this year's flu vaccine. According to CDC estimates, approximately 112 million people have been vaccinated against influenza so far this year, or approximately 37% of the U.S. population over the age of six months. "It's a little higher among children with an estimate of 40%, and 35% in adults," noted Melinda Wharton, acting director for the National Center for Immunization and Respiratory Diseases. "Influenza vaccination is continuing and our expectation is that as the season progresses, that coverage will rise," she said. "[Last year] it was 48% by end of the influenza season for the general population, six months of age and older."

The number of flu shots administered over the past several years has steadily increased, Frieden added. "We're seeing that work sites and pharmacies are major sources of vaccination for adults, with more than a third of the vaccines being given either at work sites or pharmacies," he said.