As reports swirl about a “quademic” sweeping the nation, it can feel like every virus is peaking at once as Americans sniffle and sneeze their way through cold and flu season.
In reality, data indicates that viral activity is abating for a few illnesses, while others are fueling the highest numbers of cases and deaths in years.
The Post has the run-down on the latest information you need to know about the winter viruses swirling across the United States to keep you safe and healthy.
Influenza
Influenza is hitting especially hard this year, with 43 states and D.C. reporting “very high” or “high” flu activity, according to the Centers for Disease Control and Prevention’s FluView surveillance report for the week ending on Feb. 1, the most recent data available.
The current flu season has already seen 24 million flu illnesses, 310,000 hospitalizations and 13,000 deaths — including at least 57 children.
The influx of cases has overwhelmed emergency rooms nationwide and forced dozens of schools to close their doors temporarily.
Notably, CDC data indicates that flu deaths surpassed those from COVID-19 for the first time since the pandemic began during the week ending on Jan. 25.
The exact cause of this intense flu season is unclear, but experts told Today.com that it’s been longer than usual, with lagging vaccination rates and multiple flu strains contributing to the surge.
Whooping cough
Cases of whooping cough, also known as pertussis, are climbing, with no signs of slowing down.
There were at least 360 cases reported nationwide in the CDC’s February 5 update to its infection tracker, up 27% from the week before.
Preliminary data suggests 2024 saw the highest number of whooping cough cases in a decade, with 32,000 cases and at least a dozen deaths — the most since 2017.
The surge in activity follows a dip in pertussis cases during the pandemic, likely due to measures like masks and school closures that reduced transmission. The CDC said the US is returning to pre-pandemic patterns, where more than 10,000 cases are typically reported each year.
The best protection against whooping cough is vaccination, but rates among children have fallen in recent years. Only about 92% of kindergarteners got their DTaP vaccine for the 2023-2024 school year, below the 95% federal target for preventing community transmission.
Measles
Measles cases are on the rise, with 14 reported so far this year across five states: Alaska, Georgia, New York, Rhode Island and Texas.
New Mexico was just added to the list this week, having reported a new case on February 11 in an unvaccinated teenager.
Two outbreaks have been identified in 2025: one in a West Texas county with high vaccine exemption rates, where 24 cases — 22 of them in school-aged children — were all in unvaccinated individuals; and another in Atlanta involving three unvaccinated family members.
This uptick is part of a larger wave of measles cases in recent years, with 16 outbreaks reported in 2024, including one in Chicago that sickened more than 60 people.
The rise in cases coincides with falling kindergarten immunization rates, now below the 95% threshold needed to prevent outbreaks, likely driven by growing vaccine hesitancy post-pandemic.
Norovirus
Norovirus has also been making waves this winter, causing stomach issues for Americans nationwide.
From August 1, 2024, to January 15, 2025, there were 1,078 outbreaks reported by 14 participating state health departments. That’s nearly double the number reported by these jurisdictions during the same period last season.
Though CDC data shows outbreaks are trending downward, they remain unusually high. Just this week, an outbreak on a Holland America Line cruise sickened nearly 120 people.
Bird flu
While avian influenza continues to make headlines, federal health officials maintain that the risk to the general public remains low.
Since March 2024, the CDC has identified 64 human cases of H5 bird flu, mostly mild and among farm workers. One death has been recorded in Louisiana, where the person had underlying health issues and had been in contact with sick birds.
The virus has swept through hundreds of dairy herds and thousands of poultry flocks, leading to egg shortages and soaring prices. The CDC said there is no evidence that anyone in the US has gotten infected with bird flu from eating properly handled and cooked poultry products.
“While there have been no documented cases of bird flu transmission from eating chicken or eggs to date, it makes sense to take sensible precautions,” Dr. Roy Gulick, infectious disease specialist at NewYork-Presbyterian/Weill Cornell Medical Center, previously told The Post. “People should not eat raw or undercooked chicken or eggs.”
As for milk, 28 states — covering nearly 65% of the nation’s production — are enrolled in the USDA’s testing program to detect bird flu, and nearly all commercial milk in the U.S. is pasteurized to eliminate harmful pathogens.
COVID-19
A bright spot this winter: the COVID-19 surge has been relatively mild.
“This is the smallest winter wave we’ve had since the pandemic began,” Caitlin Rivers, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, told NPR.
However, COVID-19 is still widespread, with more than half of U.S. states reporting “high” or “very high” viral activity levels in wastewater, according to CDC data from February 6.
One reason COVID-19 has taken a backseat this winter could be lingering immunity from a large, late-summer surge, Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco, told The New York Times.
Additionally, no new variant has emerged that evades the immunity people have built up, and more people received this year’s vaccine compared to last year, CDC data shows.
RSV
CDC data shows that respiratory syncytial virus (RSV) cases are on the decline in most parts of the country. Maine and Missouri are currently the only two states where wastewater indicates “very high” levels of RSV.
“This year is not too bad. Many people think we’re at the peak” of RSV infections, Peter Chin-Hong, a professor and associate dean for regional campuses at the University of California, San Francisco, School of Medicine, told Scientific American.
The relatively low RSV wave this winter is partly due to the introduction of new vaccines. The first RSV vaccine, approved in May 2023, targets those 60 and older, and people 50-59 at high risk.
The Food and Drug Administration has also approved a monoclonal antibody to protect babies and young children from severe RSV, along with a vaccine for pregnant women to protect their infants.
