Your throat's scratchy and you're starting to cough. You're pretty sure you have a fever and your body's 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 at least 36 million people in the U.S. have contracted the flu so far this season. Of the people who have seen the doctor, more than 502,000 people have been hospitalized. Between Oct. 1 and April 13, the CDC estimates as many as 57,300 people have died from the flu.
While cases of the flu have been reported in every state, 11 states are currently experiencing a widespread outbreak. With 21 weeks of elevated activity, that makes this the longest flu season in a decade, according to the CDC. The previous high was 20 weeks and was in the 2014-15 flu season, CDC spokeswoman Kristen Nordlund told CNN. "This season has been record-breaking in terms of duration," she said.
According to the CDC, although this flu season hasn't been as severe as past years, flu activity was elevated across the nation as recently as late March. The CDC says the percentage of outpatient visits for flu-like symptoms for the week ending March 16 was at 4.4 percent, which is above the baseline of 2.2 percent.
While these numbers may seem high, the CDC announced that this year's flu season "has been a low-severity influenza season, with a lower percentage of outpatient visits for influenza-like illness, lower rates of hospitalization and fewer deaths attributed to pneumonia and influenza, compared with recent seasons."
Last year was one of the worst flu seasons on record. More than 80,000 people, including 180 children, died from the flu and related complications during the 2017-2018 season — the highest number since 1976 when the data was first published.
Here's a look at what else we can expect for the 2018-2019 flu season.
When should you get your flu vaccine this year?
The CDC tells doctors they can vaccinate patients as soon as the flu vaccine becomes available. But 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 than October 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 2018 to 2019 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.
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. In February, the CDC said the vaccine was more effective than last year's vaccine, which was 36 percent.
For 2018-2019, the vaccine is targeting
- Influenza A/Michigan/45/2015 (H1N1)pdm09-like virus
- Influenza A/Singapore/INFIMH-16-0019/2016 A(H3N2)-like virus (updated from last seasons vaccine)
- Influenza B/Colorado/06/2017-like (Victoria lineage) virus (updated from last season's vaccine)
- Influenza 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, it appears that this year's vaccine is effective because it contains the right strains. The CDC reports that 90 percent of flu cases involve H1N1, which is the vaccine's primary target. That means you should get the flu shot because the chances are high that you'll be protected.
Editor's note: This article has been updated since it was originally published in September 2018.