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. Although it's still early, here's a look at what we might have in store for the 2018-2019 flu season, according to the Centers for Disease Control and Prevention.

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.

little girl getting a flu shot The flu shot is recommended over the nasal spray for most children. (Photo: Yuganov Konstantin/Shutterstock)

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 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.

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 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

It's impossible to predict in advance how effective the flu vaccine will be. The CDC monitors viruses as they circulate and provides informative about effectiveness once flu season is underway. The flu vaccine in 2017-1018 was only about 36 percent effective, so health officials are hoping for much better coverage this season.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

What you need to know about the flu this year
The flu vaccine is your best weapon against the flu this year.