WASHINGTON – Suspicions and misconceptions about the flu vaccine are everywhere.

Some say they caught the virus despite being vaccinated, others say they’ve heard this year’s vaccine is ineffective and others worry they got vaccinated too early — or too late — for it to work.

Here’s the bottom line: The flu vaccine, this year and all years past, remains the single most effective precaution a person can take to avoid getting the flu.

But it’s only about 60 percent effective.

That’s the point Dr. Anthony Fauci, one of the nation’s leading infectious disease experts, drove home on Wednesday when he was a guest on WTOP’s “Ask the Doctor” show.

“If you haven’t been vaccinated, get vaccinated,” Fauci said, repeating a directive he said many times, and many different ways, over the course of the interview.

“There is no guarantee that if you get the shot, you won’t get flu. But it’s the best thing you can do to avoid the flu, and it can dampen the severity of the illness.”

Fauci, director of the National Institute of Allergy and Infectious Diseases and key White House adviser, dispelled many myths about the vaccine on Wednesday, spoke about the severity of this flu season and discussed the future of flu treatment.

Part of the confusion surrounding this year’s flu season and the efficacy of the vaccination is that there are many different flu strains, as well as other viruses that are circulating with influenza, Fauci says.

“You may have gotten another virus that is not influenza,” he said. “And even though you may have gotten true influenza and recovered, you could still get another influenza.”

For example, norovirus is circulating with influenza this year, Fauci says. This causes gastrointestinal problems that many confuse as flu-related, but are not.

One of the predominant flu strains this season is H3N2, which the current vaccination is well-matched to immunize against. However, a person who was vaccinated can still contract another strain, which does not mean the vaccination was ineffective, Fauci says.

Further, the vaccine takes two weeks to become effective in a person’s body, and continues to build the body’s immunity from there. Doctors recommend people get vaccinated early so they have enough time to develop immunity. The vaccine’s effectiveness does not diminish over the flu season, Fauci says. So those worried their September vaccination is no longer effective can rest easy.

But, even if you’ve already had the flu, it’s still a good idea to get an immunization, because it may protect from getting another strain.

The flu season is at its halfway point right now, Fauci says. And while many have declared it an epidemic and the worst season of the decade, Fauci says that’s not necessarily true.

“We can’t say right now that this is worse than we’ve seen in a previous year,” Fauci says. “But it’s certainly substantial.”

The severity of a flu outbreak is not homogenous nationwide. Some areas get affected first, and when the threat wanes in one region, it may begin building in another, Fauci says.

A person who contracts the virus will be contagious one day before experiencing symptoms and for up to seven days after diagnosis, so it’s important for everyone who feels they may be sick to avoid infecting others.

Each year, people are encouraged to get the newly created flu vaccine, and that’s because the flu behaves differently than other ailments people are vaccinated against, such as measles, mumps or polio.

“The flu changes enough each year that the vaccine you had the previous year isn’t optimal,” Fauci says. “That’s why we have to go through this process every year of getting the best possible vaccine.”

But a solution could be on the way, he says.

“A universal vaccine that works against the parts of the flu that don’t change every year is the solution,” he says. “We’re working on that, but it’s not available yet.”

He says once that is created, and he has confidence it will be: “We’ll be able to vaccinate people every several years, and we won’t have this rush to get the most updated version each year.”

As for further precautions, a healthy lifestyle is the best bet, Fauci says. Eat healthy, exercise and get plenty of sleep. In addition, washing your hands regularly is strongly recommended. Avoid places where people are openly coughing or sneezing and wipe down common areas with disinfectant wipes.

But, more than anything else: Get the flu shot, Fauci says.

Fauci discussed many flu-related topics during the show, including vaccinations for those with egg allergies, high-risk groups and specifications on who should get vaccinated when. To learn more, read the blog below.

Follow WTOP on Twitter.

(Copyright 2013 by WTOP. All Rights Reserved.)