Hopes are soaring that children under age 12 soon will be able to get vaccines to prevent COVID-19.

And, research taking place at Children’s Hospital Colorado on the Anschutz Medical Campus will help provide key answers. Doctors at Children’s Colorado plan to test the Pfizer BioNTech COVID-19 vaccine this summer on children ages 5 to 11. Later, the team is expected to test the vaccine on babies and children, ages 6 months to 4 years old.

The results will be closely watched since anyone age 12 and older easily can get vaccines now at walk-in clinics and parents of younger children are eager to protect their families too.

“There’s overwhelming interest in COVID-19 vaccines for children,” said Dr. Eric Simões, a pediatric infectious disease expert who is leading the Pfizer clinical trial at Children’s Colorado.

Getting younger children vaccinated as soon as possible will allow kids to return to full-time, in-person school as soon as possible and help end the pandemic.

“It’s crucial that children get vaccinated,” said Dr. Lalit Bajaj, a pediatric emergency medicine specialist, who is helping oversee the Pfizer study and other vaccine trials at Children’s Colorado.

As the pandemic is easing in the U.S., the majority of COVID-19 cases in Colorado and the U.S. now are afflicting younger people.

“We still see kids sick with COVID-19,” Bajaj, who is also a professor of Pediatrics and Emergency Medicine at the University of Colorado School of Medicine. “Some of these children are very, very sick. There’s an impact on the patients themselves and on the community as a whole.”

Simões and Bajaj said the newest COVID-19 variants are highly transmissible, meaning they spread very easily, especially in children

“We really need to get a significant number of children vaccinated in order to get ahold of this pandemic,” Bajaj said. “Then we can get back to some normalcy.”

“These vaccines are crucial for society as well as for the kids themselves,” said Simões, who is also a professor of Pediatrics at the University of Colorado School of Medicine and a professor of Epidemiology Colorado School of Public Health.

Vaccines so popular that volunteers enter a lottery

The Children’s Colorado Pfizer clinical trial site is one of about 80 across the country. For the study on children ages 5 to 11, doctors at Children’s Colorado plan to give vaccines or placebo to about 250 children. Across the country, about 4,600 children will be involved in the study.

Parents have been so excited to have their children participate in clinical trials for COVID-19 vaccines that Pfizer created a website where parents could sign their children up as potential volunteers. Study managers in Colorado then conducted a lottery to select participants.

Simões said the roster of volunteers for the clinical trial is already full.

As with the adult clinical trials, researchers around the world and in Colorado have worked hard to include a diverse pool of study participants in clinical trials.

“The groups that have been particularly affected throughout the pandemic have been minority populations,” Simões said. “We’ve done a lot of outreach to different minority populations: Black Americans, Latin Americans and Asians.”

When the research begins in Colorado, study participants will receive their first and second doses of the vaccine or a placebo three weeks apart, just like adults. Participants will be enrolled in this trial for approximately two years to determine how the vaccines work in protecting children from COVID-19 over the long term.

The researchers expect the vaccines to work as well with young children as they have in adults and teens.

“It’s really well tolerated,” Bajaj said.

How the COVID-19 vaccine clinical trial at Children’s Hospital Colorado will work

Children who volunteer for the study will receive either the real Pfizer vaccine or a placebo. In adults, half of the study volunteers received the vaccine while half received a placebo. In the clinical trials for children, more volunteers get the real vaccine. Two children will get the real vaccine for every one child who receives the placebo.

The children who participate will return to Children’s Colorado for follow-up visits so researchers can test the level of antibodies in their blood. The young volunteers need to be comfortable receiving vaccines and giving blood.

After six months of follow-up, families will learn if their children received the real vaccine or a placebo. This is known as “unblinding.” At that time, any child who received a placebo will be able to get the study vaccine. Unblinding will occur earlier if federal health officials grant an Emergency Use Authorization to allow the Pfizer vaccines for children ages 5 to 11.

The research at Children’s Colorado is known as a combined Phase 2-3 study. Researchers are trying to learn if a larger group of young children have similar antibody responses to older kids, teens and adults. Among adults and teens, the COVID-19 vaccines have been excellent, preventing serious illness and hospitalizations as much as 95% of the time, while producing excellent immune responses.

Simões is confident that the clinical trials will prove that the vaccines are as safe for young children as they are for teens and adults.

“There is no reason to think that something unsafe is going to happen when children receive vaccines,” Simões said. “These vaccines appear to be very safe.”