As holiday festivities and colder weather converge, a familiar and unwelcome guest is making its presence felt across the country: the flu. This respiratory season is shaping up to be a significant one, with influenza activity rising sharply in many regions, echoing concerns from last year's severe season.
Regional Hotspots and Holiday Spread
While flu activity is not yet at its national peak, certain areas are experiencing high levels of transmission. Data from the Centers for Disease Control and Prevention (CDC) for the week ending December 6 highlights several states reporting elevated flu activity. New York, Colorado, New Jersey, and Louisiana are among the hardest-hit regions, with New York City specifically reporting "very high" levels—the highest category.
Dr. Daniel Varga, Chief Physician Officer at Hackensack Meridian Health in New Jersey, points to population density as a key factor. "When you have the kind of population density that New York and New Jersey have... you really run the risk of accelerated transmission," he explained. His health network is currently seeing a 30% test positivity rate for flu in emergency departments and clinics, starkly higher than the 2-3% rates for COVID-19 and RSV.
Other regions, including Connecticut, Idaho, South Carolina, Georgia, Michigan, Texas, Massachusetts, and Puerto Rico, are reporting moderate activity. "It’s kind of dispersed throughout the country right now," noted Elisabeth Marnik, Chief Science Officer at the public health organization Those Nerdy Girls.
The pattern of spread is familiar and concerning. Dr. Neal Shipley, Medical Director of Northwell Health-GoHealth Urgent Care in New York, observed a rapid shift. "We went from having almost no flu activity to, right after Thanksgiving... a pretty sharp uptick." Children often contract the virus at school or daycare, then bring it to family gatherings, fueling a potential post-holiday surge. Experts warn that cases are expected to remain elevated and even increase again after Christmas and New Year's, with the season lingering well into spring.
A More Transmissible Virus and Available Protections
A primary driver behind this year's concerning outlook is a mutation in the circulating flu virus. The dominant strain is H3N2, which has undergone significant changes. "When that happens, that means that our immune system doesn’t recognize it as well, so then more people are likely to get sick because they can’t fight it off as well," Marnik stated. Dr. Shipley confirmed this strain accounts for roughly 85-86% of current cases.
This mutation, also behind surges in countries like Japan and the United Kingdom, raises alarms. "Last year was one of the worst flu seasons on record for pediatric deaths, and there's some concern that this season could be as equally bad, if not worse than last year," Marnik cautioned. States like Colorado and North Carolina have already reported pediatric flu deaths this season.
Unlike a cold that starts gradually, influenza typically strikes fast and hard. "Within one or two days of exposure, most patients are going to have fever, chills, coughs, body ache, they’re going to feel pretty lousy," described Dr. Shipley. Children may also experience gastrointestinal symptoms. Early testing—via at-home kits or a doctor's visit—is crucial, as antiviral treatments for flu and COVID-19 are most effective when started promptly. These treatments are especially important for high-risk groups, including adults over 65, children under 4, individuals with conditions like asthma or heart disease, and pregnant people.
Flu can lead to serious complications like bacterial pneumonia, resulting in hundreds of thousands of hospitalizations and tens of thousands of deaths annually. If symptoms like difficulty breathing, chest pain, or a persistent fever develop, seeking immediate medical attention is vital.
How to Stay Protected This Season
Health experts emphasize that it is not too late to take protective measures. Vaccination remains a cornerstone of defense. "The current data shows that if you define vaccine effectiveness as preventing hospitalization in adults, the current vaccine is about 30 to 50% effective in preventing hospitalization, and in kids, it’s about 70 to 75% effective," said Dr. Shipley. "So, that’s pretty good."
Given that flu is an airborne pathogen, masking is a highly effective strategy, particularly in crowded indoor spaces like airports or trains. "Wearing a well-fitting N95 is a great way to protect yourself from getting sick," advised Marnik. Improving ventilation by opening windows or using air filters can also reduce risk.
Additional layers of protection include diligent hand washing, disinfecting high-touch surfaces, maintaining good sleep habits, and sticking to an exercise routine. Dr. Varga also pointed to vaccine hesitancy as a potential contributor to the season's early severity, underscoring the importance of immunization not only for personal protection but also to reduce community spread.
"Influenza can be a really bad disease... people across the age spectrum tend to die every year from influenza," Varga concluded. "You don’t take influenza lightly." With several weeks of peak activity still ahead, proactive steps are essential for navigating this flu season safely.
