It seems that the longer weve waited for a COVID-19 vaccine to be approved for certain age groups, the less likely kids in those age groups are to actually end up getting vaccinated.

The Food and Drug Administration authorized emergency use of the vaccine in kids ages 5-11 at the end of October, yet nine months later, only 30% of children in that age group have been fully vaccinated. The Pfizer-BioNTech and Moderna vaccines were authorized in June for ages 6 months to 4 years , but only 4% of kids those ages have received a first dose.

That number is likely to remain low, as a Kaiser Family Foundation (KFF) COVID-19 Vaccine Monitor survey released Tuesday found that 43% of parents of children 6 months to 4 years old will definitely not get them vaccinated. And enthusiasm for the vaccine only goes up marginally from there: Another 13% say they will only vaccinate their child if required to do so for school or daycare, and 27% said they wanted to wait and see how the vaccine is working for other young children. The remaining parents, who have already vaccinated or plan to do so right away, only make up 17% of the 471 parents of children under age 5 who were surveyed.

The survey also asked parents to explain their reluctance to having their children vaccinated. We presented some of their most common concerns to medical experts to see how they would address them with parents. Heres what they had to say:

Concern: The vaccine is too new.

The No. 1 concern raised by vaccine-hesitant parents in the KFF survey was that the vaccine is too new, or has not undergone enough research or testing.

The vaccine isnt new. This has been around for some time, said Dr. Amesh Adalja, senior scholar at the John Hopkins Center for Health Security.

Dr. Ruth Kanthula, a pediatric infectious diseases specialist at MedStar Health, explained several factors that led to the COVID vaccines relatively quick development. While you may not have heard of it before the pandemic, the mRNA technology scientists used to create the vaccine was discovered in the 1960s.

During the COVID-19 pandemic, there was a large infusion of funds to support clinical trials for the mRNA COVID-19 vaccines, Kanthula said.

The increased funds allowed research programs to hire more staff to work across multiple sites and to help manufacture the vaccines. Additionally, clinical trials were able to recruit a large number of study participants, including children, in a short period of time. This allowed for vaccine safety and efficacy data to be reviewed sooner than past vaccine trials.

Adalja also pointed out that newness isnt a reliable proxy for danger. Just because something is new, thats not evidence that its unsafe, he said, adding that we dont hesitate to purchase the newest version of the iPhone over safety concerns.

At some point, every piece of technology that improved human life was new, Adalja said.

Concern: Im worried about side effects.

No one wants to see their child in pain or discomfort, but side effects like fever and soreness at the injection site are fairly common after many vaccines. These can happen with the COVID-19 shot and tend to pass quickly.

Parents may also worry about more frightening side effects that they have heard people talking about or seen on social media. There were reports last year, for example, of myocarditis and pericarditis (inflammation of the heart muscle and the lining around the heart, respectively) mainly in young men after their second dose of the vaccine. This sounds scary, but most patients recovered quickly, and the incidence was very low: the highest rate, among 16-17 year old males, was 105.9 cases per 1 million does of the Pfizer-BioNTech vaccine. Thats a 0.0001% risk much lower than the risk of complications from COVID-19.

Concern: COVID-19 is usually mild in young children.

Thankfully, its true the COVID-19 infections in children are generally mild. Infections only rarely result in the kind of symptoms that would land a child in the hospital. But Adalja poses this question: Why not minimize any risk of it with a vaccine that is safe?

He explained that illnesses such as rotovirus and chickenpox also rarely cause severe illness, yet we routinely vaccinate against these diseases.

And just because cases are generally mild doesnt mean issues cant happen. When infections with the omicron variant surged last winter, so did pediatric hospitalizations. Nine in 10 children ages 5-11 who were hospitalized during the omicron wave were not vaccinated meaning their hospitalizations were likely preventable.

Yes, children tend to get milder infections, said Kanthula. However, children are still at risk for severe infection requiring hospitalization, supplement oxygen and possible intubation placement of a breathing tube.

Furthermore, pediatricians are limited with regards to the medications we can use to treat COVID-19 infection in children, Kanthula added. Treatments such as Paxlovid and monoclonal antibodies are only approved for ages 12 and up.

There is also the small but real threat of MISC-C , a condition in which COVID-19 infection precedes an immune response in the body that causes inflammation of the heart, lungs, kidneys or other organs. Vaccination offers protection against this serious complication.

A recent study found that 6% of children seen in emergency departments who tested positive for COVID-19 reported 90 days later that they were experiencing symptoms of long COVID such as fatigue, lethargy, and cough. Children so sick that they were hospitalized were more likely to report long COVID symptoms. By preventing severe illness, the vaccine protects children against long COVID.

Concern: The vaccine isnt very effective.

You many have heard people talking about their vaccinated children becoming infected with COVID-19. While its true that a child, or an adult, may still test positive for COVID after getting vaccinated, this isnt the most important measure of a vaccines effectiveness.

Vaccination offers strong protection against severe disease and complications. If your vaccinated child does get COVID-19, Adalja said, its unlikely theyre going to need to be hospitalized. That, he noted, is the true goal of vaccination.

What were really trying to prevent is severe disease, he said.

Concern: My child already had COVID-19.

At this point in the pandemic, a majority of children have had COVID-19. The Centers for Disease Control and Prevention reported that by February 2022, 75% of children and adolescents had antibodies, indicating prior infection.

Since infection brings temporary protection against the disease, parents may wonder if it is still worth having their children vaccinated. Experts stress that it is.

Hybrid immunity, meaning from both prior infection and vaccination, is the best type of immunity to have, offering the most protection against multiple variants of the disease, Adalja said.

Concern: Im confused about the dosing.

Some parents are confused about the varied dosing of childrens vaccines. The Pfizer-BioNTech vaccine, for example, is given in two 10-microgram doses to children ages 5-11, and in three 3-microgram doses to children 6 months to 4 years. A 4-year-old and a 5-year-old, however, arent very different in size, and a parent may wonder, for example, if they should wait until their child turns 5 in order to receive the higher dose.

But dosing doesnt hinge on a childs weight. The dosing is based on what is the minimum amount of vaccine dose necessary to gain a sufficient immune response, said Adalja, who noted that it took so long for 5-to-11-year-olds because they were trying to get the dosing right in order to minimize side effects.

As a pediatrician, said Kanthula, I know children are not little adults and one vaccine dose does not fit all. Children have different physiologic and immune responses depending on their age.

For some, there are other barriers to getting the vaccine for their kids.

One of the biggest predictors of whether or not a child gets vaccinated has nothing to do with their health. The KFF survey found that parents who identified as Republican or Republican-leaning were most likely to say they were definitely not planning to vaccinate their children.

Other parents concerns were less ideological and more financial or logistical. The survey found that 44% of Black parents with children ages 6 months to 4 years worry about needing to take time away from work to vaccinate their child or care for them if they have side effects. And 45% of Hispanic parents with children of the same ages said they worried about not being able to get their child vaccinated at a place they trust.

One potentially hopeful finding is that 70% of parents of children ages 6 months to 4 years said that they had not yet spoken to their pediatrician about vaccinating their child, meaning that health care providers may have an opening to allay families concerns in person when they bring children in for checkups. But theres no need to wait for your annual visit. If you have questions about the vaccine, call your pediatrician and make an appointment to discuss them.