Children's Hospital Colorado

Study Shows Pfizer-BioNTech Vaccination 93% Effective at Preventing Hospitalization in 12- to 19-year-olds

Children's Hospital Colorado | October 28, 2021

A study published last week and co-authored by Aline Maddux, MD, found that full vaccination with the Pfizer-BioNTech mRNA vaccine was 93% effective in preventing hospitalization for COVID-19 in adolescents and teens — even as the highly contagious delta variant became the dominant strain in the U.S.

Dr. Maddux, a pediatric critical care specialist at Children's Colorado, was part of a team of researchers at 19 pediatric hospitals in 16 states who contributed to the study, Effectiveness of Pfizer-BioNTech mRNA Vaccination Against COVID-19 Hospitalization Among Persons Aged 12–18 Years. The evaluation was supported by the Centers for Disease Control and Prevention and coordinated by Boston Children's Hospital.

Among 179 teens and adolescents hospitalized with COVID-19 from June to September, 173 (97%) were unvaccinated and only six (3%) were vaccinated. Nearly half (43%) of these young people were admitted to an intensive care unit (ICU), and 29 (16%) required life support. Two of those critically ill adolescents died. All of the patients who were admitted to the ICU, required life support and died were unvaccinated.

"Not one of the patients who were admitted to the ICU or who died had been vaccinated against COVID-19," said Dr. Maddux. "Put another way, none of the kids who were vaccinated ended up in the ICU or died — Our findings reinforce the effectiveness of the vaccine and demonstrate its ability to protect against severe, life-threatening illness due to COVID-19 across a diverse population of teens and adolescents in real-world circumstances during a period when the rate of COVID hospitalizations in children was higher than any other time in the pandemic."

Results highlight the importance of vaccinating more adolescents and teens ahead of the holidays

Currently, 63% of all kids ages 12- to 19-years-old in Colorado are vaccinated. This vaccination rate is encouraging but it reminds us that many adolescents and teens in Colorado are unvaccinated and remain at risk for severe COVID-19 and the life-threatening complications that can come with it including severe pneumonia and organ failure that can progress to death.

"While overall, the number of kids getting severe COVID-19 and being hospitalized is much lower than the number of adults, we have a tool that can prevent these hospitalizations and deaths in children, and we should use it," said David Brumbaugh, MD, Children's Colorado's Chief Medical Officer. "This study confirms that the best way to protect kids is to make sure they're vaccinated as soon as possible — especially with the holidays approaching and more families gathering indoors."

Vaccinations protect kids and the immunocompromised while keeping youth in school

In addition to protecting children from infection and related complications, the COVID-19 vaccine also makes it less likely for kids to get long COVID, or post-acute COVID-19 syndrome, which includes a variety of symptoms such as fatigue, brain fog, cough and muscle pains that persist for weeks and even months, said Sean O'Leary, MD. Additionally, because many children live in homes with caregivers who are immunocompromised and may not respond as well to vaccination (about 3% of the U.S. population), getting those children vaccinated plays an important role in protecting vulnerable community members. Yet another reason for adolescents and teens to get vaccinated is that if they're exposed to someone with COVID-19, they no longer must quarantine.

"This is critical because we know how important in-person school is to kids' learning, socialization and mental health," Dr. O'Leary, an infectious disease specialist, said. "It's essential to keep kids in school throughout the winter months to avoid many of the factors that contributed to increased behavioral health concerns in kids the year before."

From a macro view, Dr. O'Leary said, the study showing Pfizer's vaccine is 93% effective in preventing hospitalization in adolescents and teens reinforces what public health officials have been saying all year: Better vaccination rates will result in fewer COVID-19 cases and deaths across the entire population of children and adults.

"The rapid development and approval of these safe, effective vaccines is nothing short of miraculous," Dr. O'Leary said. "We were hoping for vaccines that were 50% effective, and we got vaccines that are 90% effective at preventing infection and even better at preventing hospitalization and death — these vaccines are a gift."