With just a few weeks left until the end of the decade, there’s still time to get the best gift possible for your health and the health of everyone around you: a flu vaccine.

According to the Centers for Disease Control and Prevention, our annual bout of phelgmy misery is well underway. As of the week of November 30, flu activity is high in 13 states, up from eight the previous week. And overall, more people across the country are going to the doctor for flu-like illnesses. People, including children, have already been hospitalized with the flu, with at least six suspected pediatric deaths reported to the CDC.

At the same time, we haven’t yet hit peak flu. According to current projections by the CDC, there’s about a 50 percent chance that the flu will reach its worst by late December, a 30 percent chance it’ll happen in January, and a 20 percent chance it’ll hit by February. That means, if you act now, you still have time to get the shot and have it reach full effectiveness before the flu season reaches its max intensity (typically it takes two weeks for our bodies to produce enough vaccine-prompted flu antibodies).

It’s too early to know with any certainty how intense this particular flu season will turn out to be. One interesting wrinkle so far is that a slim majority of cases are being caused by strains of influenza B virus, rather than influenza A (there are four types of influenza—in alphabetical order—but only A and B infect us seasonally).

Influenza A viruses are considered more dangerous because they mutate quickly and can be transmitted across different species of animals. That gives them the potential to rapidly infect and seriously sicken large populations of people throughout the world, every so often causing pandemics. And it also makes predicting the right vaccine for them a general nightmare. By contrast, influenza B viruses only infect humans, mutate slower, and they’ve never been thought responsible for a pandemic.

Typically, cases of influenza B are also milder than influenza A, and it’s usually easier to prepare an effective vaccine against them. But that doesn’t necessarily mean this year’s vaccine will be especially protective against all flu viruses going around.

Flu vaccines offer protection against three to four strains of flu expected to show up the next season. But sometimes, as happened last flu season, a strain of flu not predicted by scientists can turn up midway. This unexpected stain, which the vaccine offered no real protection against, lowered the overall effectiveness of the 2018-2019 vaccine to 29 percent—the lowest seen since 2014-2015.

There’s no clear indication right now as to how effective this year’s vaccine will be, but that doesn’t mean it’s not worth getting vaccinated. Flu vaccines, even if they don’t wholly prevent illness, still reduce the chances of developing a serious case of flu, and they lower the risk of spreading the flu to people who are unable to be vaccinated, such as the very young or immunocompromised.

During the especially deadly 2017-2018 flu season, for instance, the vaccine is thought to have prevented around 3.7 million doctors’ visits, 100,000 hospitalizations, and nearly 10,000 deaths, despite the fact that it was only 38 percent effective and that only a third of adults got it.

The vaccine also never will give you the flu, no matter what your cousin’s friend’s neighbor swears to you.

So please, do yourself and your community a favor. Get the flu shot or spray, wash your hands frequently, and stay home if you’re ill.