If it feels like everyone you know has COVID, you're not alone. Cases are on the rise, and so are hospitalizations and deaths. So the federal government's release of new, updated COVID boosters feels like good timing.

On Monday, the Food and Drug Administration approved the new shots; on Tuesday the Centers for Disease Control and Prevention weighed in with recommendations for who should get them. Short answer: Everyone ages six months and up.

The vaccines should be available starting this week at a pharmacy near you. So how fast should you roll up your sleeve? And why do we need another booster anyway?

We have answers from physicians, infectious disease researchers and federal officials.

1. Why do federal health officials think Americans need another round of COVID boosters?

Just as the flu vaccine is updated every year to target the viruses likely to be circulating in the fall and winter, health officials say an updated COVID shot can help bolster people's waning immunity as we head into respiratory virus season.

The new boosters are a much closer match to currently circulating variants than prior vaccines, say federal health officials. They're updated versions of the existing Moderna and Pfizer-BioNTech vaccines and have been formulated to target a relatively recent omicron subvariant called XBB. 1.5.

2. Will they protect against the newest COVID variants?

Though new variants have emerged since the FDA developed the booster, the updated shots are still "very closely matched to all the circulating strains," says Andrew Pekosz, a virologist and immunologist at Johns Hopkins Bloomberg School of Public Health.

That includes BA.2.86, a new strain that authorities began tracking in August. When it first emerged, BA.2.86 set off alarms because it had so many mutations. But a spate of recent lab studies suggest it is no better at evading immunity than other circulating variants, and the new COVID boosters should still provide protection.

"I think there's every reason to expect that people will make decent antibodies against the variants that we know about right now," says Deepta Bhattacharya, a professor of immunology at the University of Arizona College of Medicine.

3. How long will protection last?

You'll get a boost in immunity within about two weeks after getting the shot that could reduce your risk of coming down with COVID – and that protection will likely last for a few months. It should also make you more likely to get a more mild case if you do get sick.

The boost in protection against severe disease – the kind of scary symptoms that can send you to the hospital – should last a lot longer. Exactly how long depends on a variety of factors including your immune system, your health, your age and your prior exposures to both the vaccines and infections. But for many people, the hope is the COVID shots can be annual, like flu shots.

"It will markedly increase your protection against getting very sick for about a year or so," says Dr. Robert Wachter, professor and chair of the Department of Medicine at the University of California San Francisco.

4. Who should definitely get a COVID booster?

If you're at high risk of severe disease from COVID, don't think twice, say doctors and infectious disease researchers. That includes people who are over 65 or those who have weakened immune systems or certain other medical conditions, such as chronic lung disease, obesity, advanced diabetes or kidney disease.

Pregnant people should also get the shot, says Dr. Paul Offit, director of the Vaccine Education Center at Children's Hospital of Philadelphia. "The goal really is to keep people out of the hospital," he says.

At Tuesday's meeting of the CDC's Advisory Committee on Immunization Practices, the CDC's Dr. Fiona Havers noted most of those who were hospitalized for COVID since January had not received last fall's booster.

The highest rates of hospitalizations are in people 75 and older, followed by kids under 6 months and then adults between the ages of 65 to 74, according to CDC data.

Johns Hopkins' Pekosz says this is why he's advised his 86-year-old mother-in-law to get the new shot right away. In fact, he told her to be "first in line," and to take all her friends with her.

CDC data shows hospitalization rates for COVID are currently highest for Black and Native Americans and Alaska Natives.

5. If I am healthy and under 65, do I really need to get it?

It's not as urgent. The risk of death or severe illness is much lower for younger, healthy people. And the vast majority already have some protection against severe disease thanks to prior infections and vaccinations.

But many experts NPR spoke with said they'd still like to see everyone who's eligible get boosted.

For one thing, "it's no fun to be sick," says Dr. Preeti Malani, a professor of medicine at the University of Michigan. "It's no fun to miss school and work and being vaccinated is likely to make whatever illness you get less severe."

And a big reason to get boosted is that it may reduce the chance that you'll pass on the virus to someone vulnerable around you, including your own family.

"I will get one. I will encourage friends and family to get one," says UCSF's Wachter. "COVID is still around and as we're seeing now it's still capable of infecting a lot of people and hurting and killing some of them," he says.

And finally, as CDC epidemiologist Sharon Saydah noted at Tuesday's meeting, there's accumulating evidence that vaccination reduces the risk of long COVID among both children and adults.

6. What about kids? What's the recommendation for them?

The CDC recommends the shots for kids ages 6 months and up. While a CDC analysis found that kids ages 5 to 17 were much less likely to get very ill from COVID compared to other age groups, kids do sometimes get severely ill, even those with no underlying medical conditions.

The majority of kids ages 6 months to 11 years who were hospitalized from January to June of this year had not been vaccinated.

Along with older people, infants under 6 months – who are too young for the shots – had the highest rates of hospitalization from COVID, according to the CDC. So the best way to protect these youngest ones is to vaccinate those around them, says Dr. Tina Tan, a pediatric infectious disease specialist at Northwestern's Feinberg School of Medicine. "We want to protect as many individuals as possible."

The CDC points to another good reason to get kids boosted: To reduce the risk of school absenteeism and to lower the chances of developing long COVID.

Not everyone agrees it's necessary to boost kids. Dr. Pablo Sanchez, a pediatrician at The Ohio State University and an ACIP committee member, was the sole vote against recommending updated COVID shots for everyone. Sanchez wanted to see more data specific to children and adolescents.

Offit, who is not on the committee, says he thinks most kids who have already received their primary COVID vaccines and are otherwise healthy probably wouldn't get much extra benefit from an additional shot.

7. When should I get the booster? If I'm healthy, should I wait for the holidays?

Federal health officials say if it's been at least two months since your last booster, you can go ahead and get the new one. And if you fall into a high risk category, most experts agree — don't wait.

For those at lower risk, there's a difference of opinion about how long to wait after your last shot. Many experts NPR spoke with say it might be better to wait longer – anywhere from three to six months since your last vaccination or infection.

"Getting a shot too soon, you know, it's diminishing returns," says Deepta Bhattacharaya.

You may want to consider timing your booster around events like holidays or travel plans when you'll be at higher risk.

John Moore, a professor of microbiology and immunology at Weill Cornell Medicine, says there's been a surge in COVID cases around Thanksgiving for the past three years, so "getting your booster a few weeks before that makes sense," he says.

On the other hand, just as timing the stock market can be a bad idea (and can cost you), timing the vaccine isn't always smart, cautions Dr. Abraar Karan, a fellow in infectious disease at Stanford University.

"It's very hard to predict when the next wave is coming," says Karan. "And there's a chance that you could get caught in that wave before you can do anything about it," he says.

8. What if I recently had COVID, do I still need a booster?

The CDC says people who've had a recent infection may wait three months to get a booster. But many people we spoke to said it's OK to wait longer.

"If you are low risk and you've been infected less than six months ago, you probably don't need the vaccine right away," says Pekosz, because "you've got some strong immunity from that infection." But he says to get it if it's been more than four to six months.

There are certain groups of people – the elderly, immunocompromised and those with underlying illnesses – who should get COVID vaccines more frequently because of their immune status, Pekosz says. So it's best to check with your doctor if you are unsure.

9. Can I get a COVID booster at the same time as a flu shot – and what about RSV?

The CDC says you can get a flu vaccine and a COVID vaccine at the same visit. "It's absolutely fine to do both at the same time," says Dr. Peter Hotez, who leads the National School of Tropical Medicine at Baylor College of Medicine. Although he says he might not do that himself because the pain at the injection site or side-effects like body aches may be less if you get the shots separately.

But most experts we talked to recommended getting the vaccine for respiratory syncytial virus, or RSV, separately.

"I think the recommendation would be if you're going in, get your flu and COVID shot, if you're eligible for RSV, maybe space that out by a week or two," Pekosz says.

For children, the CDC recommends talking to your pediatrician about scheduling the COVID and flu vaccines and RSV preventive treatment.

10. Do I have to pay for the booster?

It depends. If you're insured, your plan should cover it, says Jennifer Kates, a policy analyst at Kaiser Family Foundation. Although if you get the shot from a provider out of your insurance network, there may be a cost, she notes.

If you're not insured, like an estimated 25-30 million American adults, the federal Bridge Access Program will provide free vaccines through the end of 2024. The CDC's vaccine.gov has information on where to get the no-cost shots. But Kates says it's not clear how many adults it will be able to cover.

Uninsured children can still get COVID vaccines and other immunizations for free under the Vaccines for Children Program.

Paying out of pocket for a vaccine would cost between $120-$129 a shot – the list price for the Pfizer-BioNTech and Moderna vaccine, respectively.