When pandemic lockdowns started, routine vaccinations and well-visits went on hold and despite safety measures and info campaigns, they've been slow to recover.
According to a new study, immunizations among five-month-olds in Texas dropped 47% from 2019 to 2020 and among 16-month-olds, they dropped 58%.
Nemours duPont Hospital worked all year to finally bring local rates to or above 2019 levels.
But that's not the case nationally.
"There are still pockets of kids out there that haven't touched the medical system since the pandemic started," said Dr. Jonathan Miller.
Dr. Miller, the division chief for primary care, is very worried outbreaks of contagious diseases are around the corner.
"As masks come off and kids and adults are sort of getting together and getting closer and sharing germs," he said.
Nemours is already seeing more common viruses. In Australia, there was a surge in RSV after the lockdown.
Dr. Laura Reich, a Cigna medical executive, says before the pandemic, some places were already losing herd immunity - the vaccination level needed to prevent outbreaks like measles.
"So it takes fewer people not to get immunized for measles to start moving around the community," she said.
Dr. Reich says it's easy for many kids to get back on track and they can catch up in one visit.
In fact, the first-ever six-in-one vaccine is now available, protecting against whooping cough, tetanus, and other diseases.
The doctors say regular checkups are also important to head off other conditions.
"For things like heart disease, which is the number one killer of Americans. So looking at their body mass index and weight, checking cholesterol, blood pressure," said Dr. Reich.
"We look for things like lead poisoning. That's something we find by doing screening in the office," said Dr. Miller.
The doctors say now is the time to get caught up.