When students in Oneida and Scott County return to school later this week, it will be amid widespread illness, including an unusual early outbreak of influenza.

The two-week Christmas break appears to have done little to squelch the spread of illness in Scott County and surrounding communities, with local physicians offices reporting full waiting rooms and widespread flu diagnoses.

At Oneida's Fast Pace urgent care clinic, patients were reportedly warned of a three-hour wait on Friday.

While the usual culprits — like gastrointestinal viruses and strep — appear to be rampant, Tennessee is one of a large and growing number of states reporting an early outbreak of flu.

Tennessee is one of 17 states reporting very high levels of flu-like illness, according to the U.S. Centers of Disease Control & Prevention.

The early outbreak of flu — flu season typically peaks in February — is not necessarily surprising. Some parts of the Southern Hemisphere, such as Australia, had a rough flu season, and that can often be an indication of things to come during the winter months of the Northern Hemisphere.

Complicating matters, this year's flu vaccine is not particularly effective. University of Tennessee Medical Center's Jennifer Radtke told the Knoxville News Sentinel last week that CDC is finding that this year's vaccine is somewhere between 10 percent and 33 percent effective.

"Any time there's a mismatch between the vaccine and the circulating strain of the flu, you're going to see more cases," Radtke told the newspaper.

In a typical year, the flu vaccine is expected to be 40 percent to 60 percent effective, the CDC says. According to reports from Australia, which used a similar vaccine as the U.S., about 10 percent effectiveness was experienced there.

Vaccines can be tricky, as global medical researchers attempt to include the strains of flu most likely to be circulating. However, the flu virus can mutate rapidly, causing vaccines to be less effective. This year's vaccine viruses included a strain of H1N1 and H3N2, among others. There were indications as early as October that this year's primary strain of flu virus had mutated and would render vaccines less effective than normal.

Even in years when the flu vaccine is less effective than desired, the CDC strongly recommends it for everyone aged six months or older, particularly the young, the old, those with compromised immune systems or chronic illnesses, and caregivers. A 2017 study by Pediatrics found that the flu vaccine significantly reduces a child's risk of dying from flu.

The authors of a New England Journal of Medicine perspective piece published in November said that everyone should receive a vaccine, no matter its shortcomings, especially with a potentially severe flu season in store.

"However imperfect, current influenza vaccines remain a valuable public health tool, and it is always better to get vaccinated than not to get vaccinated," they wrote.

While most flu deaths in the U.S. occur among the elderly, children and even healthy adults can be susceptible. A North Carolina child died of flu two weeks ago, and the CDC reports that 12 children have died nationwide as a result of the flu. A total of 45 children under the age of 18 have been hospitalized with flu-like illness.

The last year with early widespread cases of flu, similar to this year, was 2014-2015. That year, 148 children nationwide died of the virus.

Of the pediatric flu deaths reported by the CDC this season, most children did not have a high-risk underlying medical condition. Five of the 12 were between the ages of five and 11, while three were between the ages of six and 23 months and two were between the ages of two and four.

Doctors recommend that people who think they may have flu be treated promptly, as early treatment can lessen the virus's severity. Flu symptoms include high fever, body aches, coughing and sore throat.

While parents will be sending their children back to school this week, medical experts say there are precautions that can be taken to protect oneself and others from flu. For starters, those who are sick are urged to stay at home until they have been fever-free for 24 hours. Sick people can also cover their coughs and sneezes with a tissue and wash their hands frequently, preferably with soap and water, and take antiviral drugs, such as Tamiflu, if they are prescribed by your doctor.

As for those who are not sick, the CDC recommends limiting contact with people who are sick, cleaning and disinfecting surfaces and objects that may be contaminated with flu, and frequently washing your hands, preferably with soap and water, but with alcohol-based hand sanitizer if soap and water aren't available. Also, the CDC says it is never too late to receive a flu shot.