Moderna has new data backing the use of its COVID-19 vaccine Spikevax at a low dose in the youngest children under the age of 6, and it’s moving forward with global regulatory submissions.
Moderna will ask the FDA and the European Medicines Agency (EMA) “in the coming weeks” to authorize Spikevax for children 6 months to under 6 years of age, the company said Wednesday. Simultaneously, Moderna has started a delayed FDA filing for emergency use authorization of the mRNA vaccine in children ages 6 to 11, CEO Stéphane Bancel said in a statement.
For the younger-than-6 age group, Moderna is using a two-dose regimen at 25 microgram per shot. That's half the strength it’s seeking for the 6-to-11 population and a quarter of that approved for primary vaccination in adults.
In a phase 2/3 trial dubbed KidCOVE, two doses of 25-microgram Spikevax showed “a robust neutralizing antibody response” in two age subgroups, along with a “favorable” safety profile, Moderna said. In both children 6 months to 2 years old and those between 2 and 6, Spikevax elicited anti-coronavirus immune responses that were “similar to” the high dose in adults, the company said. The trial therefore met its primary goal in these age groups.
But when it comes to efficacy against COVID-19 infection, Spikevax was just 43.7% effective in children 6 months to 2 years old, and 37.5% effective in those from 2 to under 6. The efficacy was “statistically significant but lower” compared to adult data, a showing that Moderna said is expected given the predominance of the omicron variant during the trial period. Existing vaccines are known to have lower potency against omicron in adults, as well.
Despite the reduction in efficacy, no deaths, hospitalizations or severe COVID was recorded in either age group.
The KidCOVE trial also enrolled children aged 6 to under 12 years. Moderna had previously found Spikevax works in that age group, and the EMA last month recommended approval of the vaccine in those older kids. But Moderna previously decided to delay a filing for that age group in the U.S. after the FDA took time to evaluate the risk of myocarditis, a condition of heart inflammation, for adolescents.
In younger kids, Spikevax’s tolerability profile was “generally consistent with” that observed in older people, Moderna said; most side effects were mild or moderate. The trial recorded no deaths or myocarditis.
Thanks to an EUA in October, Pfizer and BioNTech’s rival mRNA shot, Comirnaty, is allowed in children as young as 5. The pair is also looking to tap into even younger children. Besides a typical two-dose regimen, Pfizer and BioNTech are also gunning for a three-dose regimen for children under 5 at 3 micrograms per dose, one-tenth of the strength for people aged 12 and above.
In February, Pfizer and BioNTech extended their rolling submission of Comirnaty in the under-5 age group to April, hoping to include the three-dose data. The companies believe the three-dose regimen may provide a higher level of protection in this age group than the two doses.