The last several falls and winters have been pretty rough in the world of respiratory viruses. The past two flu seasons have been the worst in more than 20 years with high rates of illness, hospitalization and death.
Flu vaccination rates in children have decreased since the pandemic and overall flu vaccination rates are lower than the 70% goal that public health experts aim for.
Beyond flu, fall and winter are a time when other respiratory viruses, such as colds, RSV and COVID-19 infect people in droves, leading to lots of sniffling, sneezing, coughing and more severe reactions in many.
As sick season approaches, doctors share their expectations of the viruses circulating this fall and winter — and what you can do to protect yourself from the circulating illnesses.
Flu season tends to start around now and last until March — that pattern is expected to continue.
Flu season tends to start in September or October and continues until March or even April, said Dr. S. Wesley Long, the medical director of diagnostic microbiology at Houston Methodist Hospital.
“And it usually peaks somewhere in that December/January timeframe,” added Long.
Flu season generally starts out with flu A infections earlier in the season and flu B infections later on in the winter, he said. Flu A and B cause similar symptoms, but flu A is more common.
“But really, it’s a long season,” Long said. Nationally, there’s already a slow increase in flu A cases, noted Long.
As mentioned above, the past several flu seasons have been really bad, and while there is no way to fully predict an upcoming flu season before it starts, there are some things that offer some insight.
“The southern hemisphere flu season always precedes ours,” Long said, and it runs during their winter — from May to September. The severity of flu season in this region often offers a picture of how ours will look.
“Really, this year, the southern hemisphere flu season was fairly typical. It wasn’t particularly bad. It wasn’t particularly good,” said Long.
Dr. Morgan Katz, an associate professor of medicine at the Johns Hopkins University School of Medicine in Baltimore, noted that flu season in this area was “lighter and later” than the 2025-26 flu season. “So, that’s slightly encouraging,” she said.
Even if the season proves to be lighter, experts told HuffPost flu vaccination is still a crucial way to protect yourself from severe outcomes if you do get sick.
Indoor gatherings are more prevalent in the fall and winter, which allows illnesses like COVID-19 to spread.
“There’s a few things that make these respiratory viruses harder to control in the winter months,” Katz said. “The big thing is that we’re inside more. We’re closing our windows, and we’re just not getting the ventilation and outdoor activity that we get during the summer months.”
These behaviors allow respiratory viruses to circulate more, whether it’s colds, COVID or the flu, Katz noted.
“It is likely that we will start to see COVID and COVID cases increase a little bit more as we gather more,” noted Katz.
Dr. David Nguyen, an assistant professor of infectious diseases at Rush University Medical Center in Chicago, added that while COVID pops up throughout the year, it does tend to increase, in general, during the winter months.
“So, we might see a peak of that in the winter months, like January, as well,” said Nguyen.
But, COVID isn’t purely seasonal, it doesn’t go away in the summer like flu and RSV do, Katz added.
RSV is a seasonal virus that is expected to run throughout the fall and winter.
Currently, RSV activity is low throughout the country, said Katz.
RSV, or respiratory syncytial virus, causes cold symptoms in healthy kids and adults, but can cause serious complications in babies and older adults.
Like the flu, RSV tends to start circulating around October and continues through the winter with a peak in January, said Nguyen.
The RSV vaccine, which is available for babies, pregnant people, adults 75 and older, and adults 50 to 74 who are at risk for complications, has already shown to be effective.
Fall and winter are also the most common time for colds.
The fall and winter months are the most common time for colds, noted Nguyen.
“We don’t have vaccines for them. We don’t have antiviral medicines for them. So the best we can do is prevent with masking if appropriate, hand hygiene, things like that,” said Nguyen.
A range of viruses such as rhinovirus and enterovirus can cause cold symptoms (cough, runny nose, congestion), noted Long.
Again, there aren’t specific treatments for these cold-causing illnesses, but taking a COVID and flu test is a good idea if you have any respiratory symptoms.
“It’s good to test yourself for flu and for COVID because they have antiviral treatments available,” Long said. If you test positive, your doctor can see if you’re eligible for treatment.
There are measures you can take to avoid all of the illnesses circulating this fall and winter.
Vaccination is the best way to stay healthy and avoid severe outcomes like hospitalization and death from the flu, COVID-19 and RSV.
“I just can’t emphasize enough that flu, COVID and RSV vaccines, if you’re eligible to get them ... I think it would be very important to try and get them and talk with your doctor about your individual risk,” Nguyen said.
Older adults, pregnant people and young infants are at particular risk for many of these illnesses, but certain vaccines are helpful for people outside of those groups, too.
Beyond vaccination, all of the prevention methods we learned during the COVID pandemic apply here and also help protect you from other respiratory viruses, noted Long.
“So, avoiding large crowds, avoiding cramped indoor spaces with large crowds, definitely avoiding people that are sick or have symptoms when you can ... if people want to, things like wearing masks may be helpful,” said Long, before adding that social distancing is also helpful.
“All the non-pharmacologic measures are good sort for any respiratory virus during the cold and flu season,” said Long. “All those sorts of things can be helpful in avoiding getting sick.”