Update: On June 17, the FDA granted emergency use authorization to both vaccines. The CDC's vaccine committee meets June 17-18 to discuss. For the latest news on COVID-19, visit http://bit.ly/AAPNewsCOVID19.
Two long-awaited COVID-19 vaccines for young children received the green light from a Food and Drug Administration (FDA) expert panel on Wednesday.
The FDA’s Vaccines and Related Biological Products Advisory Committee (VRBPAC) voted 21-0 in favor of the vaccines from Moderna and Pfizer- BioNTech that cover children down to 6 months.
If the FDA commissioner authorizes the vaccines, they will go before the Centers for Disease Control and Prevention’s (CDC’s) Advisory Committee on Immunization Practices (ACIP), which is scheduled to meet Friday and Saturday. If the CDC director signs off after the ACIP meetings, this final group of children under 5 years would become eligible for protection a year-and-a-half after adults.
“As a pediatrician, today is a red-letter day,” said VRBPAC member Archana Chatterjee, M.D., Ph.D., dean of the Chicago Medical School at Rosalind Franklin University of Medicine and Science. “For me to be able to vote for authorization of two vaccines that will protect children down to 6 months of age against a deadly virus is a very, very important thing.”
Vaccines for this age group took extra time, experts said, due to their vulnerability. VRBPAC members heard in-depth presentations from both manufacturers and the FDA on Wednesday.
Moderna’s vaccine for children ages 6 months through 6 years is given as two 25-microgram (µg) doses one month apart. While the vote Wednesday was on a two-dose series, the company said it expects a third dose will be needed and is gathering data on that additional dose.
In clinical trials involving 5,000 children, most systemic reactions were mild or moderate. The most common were irritability/crying for children ages 6 months through 36 months and fatigue for those 37 months through 5 years. Fevers were reported in about 8%-19% of children depending on the age and dose. None of the children in the trials experienced myocarditis/pericarditis. Lymphadenopathy-related events were reported in about 1.5% of those under 2 years and 0.9% of those over 2 years.
Across all ages, one serious adverse event (one child with pyrexia and febrile convulsion) occurred that may have been related to vaccination but also could have been due to a viral illness, according to the FDA.
Looking at antibody titers, the geometric mean concentration (GMC) ratio was 1.28 for the youngest group and 1 for the older group when compared to young adults.
Vaccine efficacy against symptomatic infection during the omicron period was 50.6% for children under 2 years and 36.8% for children 2-5 years.
Wednesday’s VRBPAC recommendation came one day after the group recommended Moderna’s COVID-19 vaccine for children ages 6-17 years.
The Pfizer-BioNTech vaccine is for children ages 6 months through 4 years. It is given as three 3-µg doses. The first two doses are given three weeks apart and the third is given eight weeks after the second dose.
In clinical trials involving 3,000 children, most reactions were mild to moderate. The most common systemic reactions for vaccine recipients were irritability for children under 2 years and fatigue for children 2 years and older. Fever after a vaccine dose was reported in about 7% of the younger group and 5% of the older group. These rates were just slightly higher than the placebo group for the youngest children and about the same as the placebo group for the older children.
Among all ages, three vaccine recipients had lymphadenopathy. About 2% of the youngest group and 1% of the older group had hypersensitivity. There were no reports of anaphylaxis, myocarditis/pericarditis or deaths.
One serious adverse event, a combination of fever and calf pain in a child in the older group, was deemed vaccine-related by an investigator, but the FDA said it may have been due to a viral infection.
Looking at immunogenicity, the geometric mean titer (GMT) ratio was 1.19 for children under 2 years and 1.3 for children ages 2-4 years when compared to teens and young adults ages 16-25 years.
Vaccine efficacy against symptomatic infection was 75.6% for children under 2 years and 82.4% for ages 2-4 years. However, several VRBPAC members said they did not put a lot of stock in these numbers given the small number of cases (three for young children and seven for older children) and short window of time involved in calculating efficacy. Confidence intervals for both age groups were wide.
Several committee members also expressed concern about the vaccine having little efficacy until the third dose.
“I do support this, but I do worry that parents aren’t necessarily going to know that after two doses they (children) may not be protected at all and may engage in the kind of activity that would put their child at risk,” said VRBPAC member Paul Offit, M.D., FAAP, director of the Vaccine Education Center at Children’s Hospital of Philadelphia.
COVID-19 in young children
More than 2 million children under 5 years have been infected with COVID-19, a figure that likely is an underestimate. Hospitalizations spiked for this age group at the height of the omicron wave this past winter, and about one-quarter of those children were treated in intensive care units. More than 400 young children have died since the start of the pandemic.
VRBPAC member H. Cody Meissner, M.D., FAAP, professor of pediatrics at Tufts University School of Medicine, supported both vaccines but noted the number of deaths from COVID-19 is relatively small in young children and that parents would have to weigh the risks and benefits.
Other members considered the death toll significant, pointing to CDC data showing COVID-19 ranks as the fifth leading cause of death among children ages 1-4 years. Some also noted death rates are higher than several other vaccine-preventable diseases.
“I do believe the benefits (of vaccination) far outweigh the risks that were involved,” said VRBPAC member Michael R. Nelson, M.D., Ph.D., chief of the Asthma, Allergy and Immunology Division of UVA Health. “Personally, I really do believe this recommendation does fill a significant unmet need for a really ignored younger population in need of options. Families will now have a choice they did not have before.”
- AAP COVID vaccination resources
- CDC clinical considerations for administering COVID-19 vaccines
- Information from HealthyChildren.org on preparing children for a COVID-19 vaccine