![a mug with lemons and tea sitting on a snow-covered table](https://www.popsci.com/wp-content/uploads/2018/12/20/SN7KCHN7KAXMMQTMKSSFSI2PSQ.jpg?quality=85&w=2560)
![a mug with lemons and tea sitting on a snow-covered table](https://www.popsci.com/wp-content/uploads/2018/12/20/SN7KCHN7KAXMMQTMKSSFSI2PSQ.jpg?quality=85&w=2560)
We’re having somewhat of a late start to this year’s flu season. Though there have already been deaths recorded in multiple states, not every part of the country is getting hit equally hard yet.
In fact, most parts of the U.S. haven’t technically hit flu season yet. We may think of the term as referring to an amorphous span of time stretching from October or November through to the spring, but the CDC has a more specific definition: the time in which levels of influenza-like illness are above the national baseline of 2.2 percent. Influenza-like illness is basically a measure of how many people report to the doctor with a fever over 100 degrees Fahrenheit plus a cough and/or a sore throat.
We’ve been holding steady right at the baseline for the last three weeks, but a handful of states are already rising above it. Georgia is ahead of the pack with an ILI just above four. Kentucky and Colorado aren’t far behind.
![ILI CDC map](https://www.popsci.com/wp-content/uploads/2018/12/20/NLDAWCYAMAON472LVQRT7EAJEA.jpg?strip=all&quality=85)
Most of the time, you probably don’t care much at all about what the flu looks like in other states. But this time of year you should. The pattern of influenza spread changes around the holidays as millions of people travel and kids come home from school. Everyone brings new virus strains with them as they go, exposing other people to versions of the flu that their immune systems are not yet familiar with, and thus influenza spreads.
This is extra important around the holidays—a lot of people visit grandparents and other elderly loved ones who are far more susceptible to the flu than the healthy young ‘uns who wittingly bring the virus along for a ride. Many of the people who die from influenza every year—and in 2017 there were 80,000 deaths—are elderly or otherwise unhealthy. It’s these people that we’re really trying to protect with the flu vaccine. Even if older people get the shot, their frail immune systems don’t mount as effective a response to the inactivated viruses, which means the vaccine isn’t as helpful for them. That leaves them more susceptible to getting sick and having serious complications. And plenty of people can’t get the shot in the first place: often patients who are on immunosuppressive drugs aren’t allowed to get vaccines. These folks are at much higher risks of developing severe problems if they get the flu, which they’re already more likely to come down with.
If you’re traveling this holiday season, especially to any of the states already experiencing flu season, please go get a flu shot if you haven’t already. They take two weeks to become fully effective, so it’s already a little late, but any protection is better than none and sooner is better than later. Things are only going to get worse over the next few weeks, and you have the power to help.