Flu Symptoms: Seasonal infections are spreading across the United States just as the holiday travel rush gets underway, worrying health officials about fresh spikes during family get-togethers. Flu and norovirus cases are rising in several states, while COVID-19 continues to circulate at lower but consistent levels. Together, these illnesses are adding strain on hospitals as millions of people plan to travel in the days ahead.Flu: What Is Super Flu?“Super flu” is not a clinical term, but it is often used to describe a flu season that feels more aggressive or spreads faster than usual. This is typically linked to a dominant strain of influenza A. The current surge is being driven by a mutated influenza A strain known as H3N2 subclade K. Health officials say this strain has become the leading flu variant in the US, accounting for roughly 89 percent of H3N2 samples analysed since late September, according to genetic sequencing data from the Centers for Disease Control and Prevention (CDC). This variant emerged after the 2025–26 flu vaccine was formulated, meaning the vaccine may not be as closely matched as in earlier seasons. While the shot still offers protection against severe disease, experts note that the mismatch could allow the virus to spread more easily.Flu Symptoms 2025: What Symptoms Should People Watch For?The symptoms seen in the current flu wave are largely familiar. People may develop fever, chills, extreme tiredness, cough, and body aches. Doctors, however, caution that the wider spread could result in more serious cases, particularly among people who are at higher risk.CDC estimates indicate that the US has already seen about 4.6 million flu cases this season, along with nearly 49,000 hospital admissions and around 1,900 deaths. Flu activity increased sharply in mid-December, with test positivity jumping from 8.1 percent to 14.3 percent within a single week.Flu Symptoms 2025: How To Reduce The RiskDoctors recommend staying home when feeling unwell, washing hands often, especially to limit norovirus spread, and considering vaccination against flu and COVID-19. Even when the strain match is not ideal, experts stress that vaccines remain crucial in reducing the risk of severe illness, hospitalisation, and death.Flu Cases In The US: How Contagious Is Superflu?In terms of how easily it spreads, it behaves much like regular flu, which is known to be highly contagious.Someone with flu can pass on the virus from around one day before symptoms appear and continue to be contagious for five to seven days after becoming sick. Children, older adults, and those with weakened immune systems may remain infectious for a longer period.The virus mainly spreads through respiratory droplets released when an infected person coughs, sneezes, speaks, or breathes near others. It can also spread through contact with contaminated surfaces, followed by touching the mouth, nose, or eyes. Crowded indoor settings, poor airflow, and close contact make transmission far more likely, which explains why flu spreads quickly during peak season.What makes a so-called “super flu” seem more contagious is not a new way of spreading, but higher case numbers, quicker community transmission, and stronger symptoms, all of which increase coughing, fever, and the amount of virus released.