WASHINGTON (AP) — Updated COVID-19 vaccines may be getting a little easier for adults to find but they're still frustratingly scarce for young children. Health officials said Thursday the kid shots have started shipping — and reminded most everyone to get a fall flu shot too.

About 2 million Americans have gotten the new COVID-19 shot in the two weeks since its approval despite early barriers from insurance companies and other glitches, according to the Department of Health and Human Services.

For the first time, the U.S. has vaccines to fight a trio of viruses that cause fall and winter misery. But health officials worry that shot fatigue and hassles in getting them will leave too many people needlessly unprotected.

"We need to use them," Dr. Mandy Cohen, director of the Centers for Disease Control and Prevention, said Thursday. "Right now is the right time."

A flu vaccination and that updated COVID-19 shot are urged for just about everyone, starting with babies as young as 6 months.

Also this year, a vaccine against another scary virus called RSV is recommended for people 60 and older and for certain pregnant women. And for babies, a vaccinelike medicine to guard against that respiratory syncytial virus is expected to arrive next month.

"These vaccines may not be perfect in being able to prevent absolutely every infection with these illnesses, but they turn a wild infection into a milder one," said Dr. William Schaffner of Vanderbilt University and the National Foundation for Infectious Diseases.

Some things to know:

WHY DO I NEED ANOTHER COVID-19 SHOT?

This year's vaccine is updated to protect against newer versions of the constantly evolving coronavirus. Already there's been a late summer jump in infections, hospitalizations and deaths. And so far the new vaccine recipe appears to be a good match to the variants currently circulating.

Protection against COVID-19, whether from vaccination or from an earlier infection, wanes over time — and most Americans haven't had a vaccine dose in about a year. Everyone 5 and older will need just one shot this fall even if they've never had a prior vaccination, while younger children may need additional doses depending on their vaccination and infection history.

HOW HARD IS IT TO FIND COVID-19 SHOTS?

The rollout's start has been messy. This time the government isn't buying and distributing shots for free. Now drugstores, doctors' offices and other providers had to place their own orders, and sometimes canceled appointments if supplies didn't arrive in time. Some people had to wait for their insurance companies to update the billing codes needed to cover them or risk paying out of pocket.

Manufacturers Pfizer and Moderna have shipped millions of doses, and say there's plenty of supply — and in recent days, more appointments have started opening, at least for people 12 and older. In a Wednesday meeting, insurance companies told HHS Secretary Xavier Becerra they've largely resolved the paperwork issues blocking some patients' vaccinations.

The shots are supposed to be provided free in-network to the insured. For the uninsured or underinsured, CDC has opened what it's calling a "bridge" program to provide free shots at certain sites.

WHY CAN'T PARENTS FIND COVID-19 SHOTS FOR YOUNGER KIDS?

Adult doses got shipped first, CDC's Cohen said. Doses for the under-12 set have begun shipping, and "the supply is filling out," she said.

Drugstore chain CVS said its doses for ages 5 and older began arriving last week, although supplies vary by location, while its MinuteClinic locations anticipate opening appointments for tots as young as 18 months in the coming days.

As for pediatricians, they've had to guess how many doses to buy up-front while waiting to learn how much insurance companies would reimburse them for each shot, said Dr. Jesse Hackell of the American Academy of Pediatrics. He said early parent demand is heartening but that pediatricians expect to spend lots of time this fall explaining to hesitant families how important COVID-19 vaccination is even for healthy children.

In Redmond, Washington, Ania Mitros got herself, her husband and her 13-year-old vaccinated pretty easily but despite calls to multiple pharmacies and clinics can't find anyone to tell her when shots for her 8- and 11-year-old will be available. "There need to be clear expectations," she said.

WHAT ABOUT FLU VACCINE?

Fewer Americans got a flu vaccine last year than before the coronavirus pandemic –- a discouraging gap that CDC hopes to reverse.

People need a flu vaccine every fall because influenza also mutates each year. Like with COVID-19, flu is most dangerous to older adults, the very young and people with weak immune systems, lung, heart or other chronic health problems, or who are pregnant.

There are multiple kinds of flu vaccines, including a nasal spray version for certain younger people. More important, three kinds are specifically recommended for seniors because they do a better job revving up an older adult's immune system.

CAN I GET A FLU SHOT AND COVID-19 SHOT AT THE SAME TIME?

Yes, although one in each arm might be more comfortable.

WHO NEEDS THE NEW RSV VACCINE?

RSV is a cold-like nuisance for most people, and not as well-known as the flu. But RSV packs hospitals every winter and kills several hundred tots and thousands of seniors. The CDC says already, RSV cases are rising in the Southeast.

RSV vaccines from GSK and Pfizer are approved for adults 60 and older.

Drugstores have adequate supplies but some seniors are reporting hurdles such as requirements to get a prescription. That's because the CDC recommended that seniors talk with their doctors about the new vaccine. Cohen said it was meant just for education about a virus that people may not know much about.

"We want folks to ... get access to the vaccine as quickly as possible," she said.

WHAT ABOUT BABIES AND RSV?

The FDA also has approved Pfizer's RSV vaccine to be given late in pregnancy so moms-to-be pass virus-fighting antibodies to their fetuses, offering some protection at birth. The CDC is recommending that pregnancy vaccinations be offered between September and January, when RSV tends to be most common.

There's no vaccine for children but babies whose mothers didn't get vaccinated in pregnancy may get an injection of lab-made antibodies to guard against RSV. Called Beyfortus, the one-dose shot from Sanofi and AstraZeneca is different than a vaccine, which teaches the body to make its own infection-fighting antibodies, but is similarly protective. Cohen said it should be available in October.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science and Educational Media Group. The AP is solely responsible for all content.