Your throat's scratchy and you're starting to cough. You're pretty sure you have a fever and your body is starting to ache. Is it a cold or could it be the onset of the dreaded flu?
Although flu can circulate year-round, typically flu viruses are spread most commonly in fall and winter. Each year, activity varies with different strains making their way around the U.S.
The Centers for Disease Control and Prevention reports that flu is in full swing in the U.S. As of Jan. 4, it's everywhere — all regions of the country are seeing elevated levels of flu and flu-like symptoms.
The CDC reports that so far this year's flu vaccine has been a good match to all strains of flu out there.
At least 9.7 million people in the U.S. have contracted the flu so far this season. Of the people who have seen a doctor, at least 87,000 people have been hospitalized. Between Oct. 1 and Jan. 4, the CDC estimates at least 4,800 people have died from the flu.
Here's a look at what we can expect for the rest of the 2019-2020 flu season.
Did you already get your flu shot?
It's key to get the vaccine before the onset of flu season, which typically starts around October and can run as late as May. Because it takes about two weeks for antibodies that protect against the flu to develop in your body after you get the vaccine, the CDC recommends getting the vaccine by the end of October. Children who need two doses of flu vaccine should start the process sooner because those doses typically need to be given four weeks apart.
That doesn't mean you're too late if your annual physical is in November or later. In the past, peak flu season activity has typically occurred in January or later, so getting a flu vaccine later can still help protect you.
Who should get the flu vaccine?
Almost everyone 6 months and older should get the flu vaccine, recommends the CDC. It's available as a flu shot and a nasal flu spray. For the 2019 to 2020 season, there's no recommendation for the shot over the spray for most people. The flu mist is approved for people who are age 2 through 49 and who aren't pregnant. People with certain medical conditions, such as a weakened immune system, should not opt for the spray. There is a high-dose vaccine available for those age 65 and older.
The CDC and the American Academy of Pediatrics (AAP) recommends the flu vaccine for children 6 months and older. The AAP recommends the flu shot over the flu spray for children "because it has provided the most consistent protection against all strains of the flu virus in recent years." For children who otherwise wouldn't get the flu shot (if they refuse to get one or if their pediatrician's office runs out), then the nasal flu spray is an option.
The National Institutes of Health also suggests that children 6 months to 8 years old take two vaccines doses in a flu season. Their study observed children in five states and found that those who only took one vaccine dose had a twofold increase of contracting the flu compared to children who took two doses. The CDC recommends that children who take two doses should receive the second dose four weeks after the first dose, and the AAP recommends two doses for children in the same age range if it's their first ever flu vaccination.
Can you get the flu vaccine if you are allergic to eggs?
Most flu vaccines are made from viruses grown in fertilized chicken eggs. This is why you may be asked if you have an egg allergy before getting a flu shot. And that's why, in the past, people with egg allergies have been cautioned to avoid the flu shot.
But the CDC clarified that people who have only had hives when exposed to eggs "can get any licensed flu vaccine that is otherwise appropriate for their age and health." People who've had more serious symptoms after egg exposure — such as respiratory distress or lightheadedness — can still get the flu vaccine. But they should get it in a medical setting (such as a hospital, clinic or a doctor's office) where they can be supervised by a health care provider who can recognize and manage a severe allergic condition.
How effective will the flu vaccine be this year?
Because there are many different strains of flu viruses, the flu vaccine is updated each year. It's formulated to address the viruses that health experts believe will be circulating the upcoming season. Typically influenza A viruses are more common than influenza B viruses, but both cause infections every season and are covered in the annual flu shot.
For 2019-2020, the trivalent (three-component) vaccines are available for seniors. They are recommended to contain:
- A/Brisbane/02/2018 (H1N1)pdm09-like virus (updated)
- A/Kansas/14/2017 (H3N2)-like virus (updated)
- B/Colorado/06/2017-like (Victoria lineage) virus
All regular-dose flu vaccines this season are quadrivalent (four-component) vaccines, which protect against a second lineage of B viruses. They are recommended to contain:
- the three recommended viruses above, plus B/Phuket/3073/2013-like (Yamagata lineage) virus
The CDC monitors viruses as they circulate and provides informative about effectiveness once flu season is underway. So far, the CDC sees flu activity being caused mostly by influenza B/Victoria viruses, which is unusual for this time of year. A/H1N1 viruses are the next most common and are increasing in proportion relative to other influenza viruses in some regions.
Editor's note: This article has been updated since it was originally published in September 2018.