The Centers for Disease Control and Prevention endorsed updated COVID booster shots on Tuesday for Americans ages 6 months and older amid rising cases and hospitalizations across the country.

It comes a day after the FDA authorized and approved the new shot that is formulated to target variants of the virus that are currently circulating.

The vaccines for Moderna, Pfizer and its partner BioNTech will be available by the end of the week in pharmacies and some doctor’s offices. It will be mostly free through private insurance, Medicare or Medicaid.

In a Tuesday night interview with ABC News Live, CDC Director Mandy Cohen stressed the importance of getting the updated shot and addressed concerns around its safety, saying the shots have been studied “more than any vaccine in history.”

LINSEY DAVIS: For more now, let's bring in the director of the CDC. Mandy Cohen, thank you so much for joining us tonight.

MANDY COHEN: Great to be with you.

DAVIS: Late today, you officially signed off on these booster shots. The shots come as we're, of course, seeing an uptick in COVID cases. How soon will the new shot be available?

COHEN: Well, today, the CDC recommended that everyone should get an updated COVID vaccine, and within the next number of days, you're going to see those start to show up in doctor's offices and pharmacies around the country.

DAVIS: Fewer than half of adults older than 65 and just 1 in 5 Americans got the booster shot last fall. Many Americans view COVID as a mild threat now. Are you concerned that very few people will opt for boosters this fall?

COHEN: Well, we'd all wish for COVID to be in the rearview mirror but, unfortunately, it's still here. And what we know is that our immunity decreases over time. So even if you've had COVID before or been vaccinated, that immunity and that protection does decrease over time. Plus, what we're seeing is that this virus, the COVID virus, continues to change. That's why today [Tuesday] the CDC is recommending an updated COVID vaccine for everyone over the age of 6 months. Again, it's to protect you from the serious consequences that this this virus still can have.

DAVIS: Many Americans, as you know, have ditched their masks. As we head into the fall and winter, do you see a world where people should mask up again in crowded spaces and inside?

COHEN: Well, as we get to the fall and winter, we're going to have not just COVID circulating, but remember, flu is out there, RSV – that impacts our young kids – is out there and other viruses. So we want to use all the tools we possibly can to protect ourselves. Vaccine is a great tool, and going into the fall and winter, we have vaccines against all three of those major viruses. So right now, ahead of fall and winter is a great time for you to get not just your COVID vaccine, but your flu shot. And if you're an older adult, to get an RSV vaccine.

But we have to use other tools, right? So if you do get sick, make sure you're getting tested, because getting tested allows you to then get treatment. And treatment makes sure that you won't get very sick, end up in the hospital. So we need to use all the tools we possibly can to protect ourselves as we get into the fall and winter.

DAVIS: You've just started this job. Beyond COVID and what we've already discussed with regard to the flu and RSV, what are your biggest health priorities at the CDC?

COHEN: Well, as you mentioned, you know, first and foremost we’re focused on these respiratory viruses. It's unfortunately the thing that is going to take a number of lives in the coming months. But we have the tools to protect ourselves. So focusing on protecting ourselves from COVID, flu and RSV is certainly a first priority.

But many other health threats that are out there, and the CDC is designed to be that asset for this country to detect and respond to threats. So other threats like declining in our mental health or the opioid crisis that we're seeing or we're seeing, unfortunately, more suicides. So that is certainly something that we are focused on at the CDC as well, making sure we can bring data and evidence and best practices to support folks not just with respiratory illnesses, but maybe their mental health and addiction as well.

DAVIS: And before we let you go, I do want to ask, for those who are concerned about the safety, the medical issues potentially down the road that they say they are concerned about with regard to getting these COVID shots. What's your response to those who are still skeptical and doubting?

COHEN: Well, I want folks to know that these vaccines have been studied, frankly, more than any vaccine in history. We've given over 600 million doses of the COVID vaccine.

So it's been studied in terms of its safety extensively. So I wouldn't recommend anything I wouldn't recommend for my own family. I'm not just the head of the CDC. I'm a mom. I'm a wife. I'm a daughter. So you're going to see my 9- and 11-year-old daughters get vaccinated with COVID and flu this fall, my husband, my parents. So we're hoping that everyone will protect themselves when we get into the fall and winter, get their updated COVID shot, as well as a flu shot.

DAVIS: CDC Director Mandy Cohen, we really appreciate your time tonight.

COHEN: Thank you. Thanks for having me.