An advisory panel to the U.S. Food and Drug Administration (FDA) voted unanimously on Wednesday to recommend two COVID-19 vaccines for kids ages 5 and younger.
The 21-0 vote for both companies is the first step in what is expected to be a quick pathway to authorization before the FDA makes a formal decision.
Though both options are mRNA vaccines, leaving no alternative for those uncomfortable with or unable to use the platform, public health officials hope for quick uptake. Both companies conducted trials as the Omicron variant of COVID-19 took hold, and the data show just how tough a target the virus and its latest strains are. Similar reduction in protection against infection was seen in the kids group as has been seen in the real world for adults, but both vaccines continued to protect against severe disease, hospitalization and death.
The FDA’s Dr. Peter Marks noted that though children have not been affected by COVID-19 at the same rate as older adults, the rate of hospitalization is concerning.
“That rate of hospitalization is actually quite troubling. If we compare this to what we see in a terrible influenza season, it is worse,” he said.
In addition, Marks said 442 children younger than 5 years old had from COVID as of the end of May in the U.S., compared to 78 from flu during the 2009-2010 H1N1 pandemic.
“Each life loss…fractures a family,” he said.
Two options, many variables
The two options parents face include two, 25-microgram doses one month apart, or three, 3-microgram doses with the first two delivered 3 weeks apart, and the third dose after 2 months.
Pfizer initially pursued a two-dose schedule but found that combination, especially as Omicron began to take hold during the trials, had an efficiency of just 28.3% for two doses. By comparison, three doses confer 80% efficacy.
Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, said it worried him that two doses afforded so little protection against the virus.
“It was a surprisingly negative result,” Offit said.
“Our robust clinical study shows that three doses can provide protection for the circulating Omicron variant and offers promise for protection against potential future waves of COVID-19. The committee’s support today is imperative to providing a critical tool for pediatricians, parents, and caregivers who eagerly await an option for children under five,” said Pfizer’s Dr. Bill Gruber, Vaccine Clinical Research and Development head.
Moderna’s two-dose vaccine for kids aged 6 months to 6 years, with trials conducted during the Omicron wave, captured a reduced protection against infections as well.
The youngest group saw efficacy of 51%, while 2- to 5-year-olds saw efficacy of 37%.
Previous Omicron infection in addition to vaccination leads to more durable protection post-vaccination, Moderna’s data found.
One member asked why previous real-world data has shown both mRNA platforms to be similar, but for under 5 years there has suddenly been a difference in number of doses required.
FDA officials said that data doesn’t exist for a side-by-side comparison, so it is hard to tell.
Another member asked, similarly, why one company is using 25 micrograms versus another using 3 micrograms.
Gruber said he couldn’t answer for Moderna, but, that Pfizer doesn’t “have a complete understanding of the nature of the way the vaccine works in terms of producing immune responses. We have to go by the results.”
The most common side effect for Moderna’s vaccine was fever, and the most common for Pfizer was fatigue, according to data presented Wednesday.
One thing that remains to be understood is the type of protection conferred during pregnancy by mothers who get vaccinated, compared to children receiving the vaccine post-birth. That will be studied in a new study of newborns through 6 months, Moderna officials said.
One member asked during Moderna’s presentation when doses should be given to kids in relation to other childhood vaccines. Moderna said it provided guidance to leave 2 weeks between flu and COVID vaccines, and a month between COVID and other vaccines.
The companies are now awaiting an FDA decision, followed by the CDC’s advisory committee, which meets Friday and Saturday to similarly hear presentations and vote on whether to recommend the vaccine. The CDC then needs to make a decision before doses are released.
The U.S. government is already poised to distribute the vaccines next week.
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