Vaccination site in March in Los Angeles. Credit … Alicia Yuchevich for The New York Times
External advisers to the Food and Drug Administration voted unanimously Wednesday to recommend that the agency authorize Moderna and Pfizer-BioNTech coronavirus vaccines for very young children, a move that could clear the way for regulators to authorize both pediatric vaccines in emergencies. later this week.
Pfizer’s three-dose vaccine will cover children aged 6 months to 4 years, while the two-dose Moderna vaccine will be for children 6 months to 5 years of age. States have already ordered millions of doses. Depending on what regulators are doing, White House officials said dose administration could begin in earnest on Tuesday.
The FDA said clinical trial data from the companies showed that each vaccine met safety and efficacy criteria in the age group.
More than two years after the pandemic, no vaccine has been allowed for children under 5 in the United States, an unmet need that has worried many parents. The FDA is expected to act immediately on the recommendations, followed by the Centers for Disease Control and Prevention later this week.
The panel of advisers voted 21-0 to recommend vaccine approval for both Moderna and Pfizer. “I know that mortality from Covid and young children may not be extremely high,” said Dr. Jay Portnoy, a professor of pediatrics at Children’s Mercy Hospital in Kansas City, Missouri. But he said, “It’s absolutely terrifying for parents to have their child sick,” or hospitalized.
“There are so many parents who are absolutely desperate to get this vaccine,” he added, “and I think we owe them a choice.”
Both vaccines, which the commission reviewed Wednesday, appear to be significantly less effective against symptomatic infection than adult vaccines when they were introduced. The FDA attributes Omicron to being much more adept at avoiding protecting vaccines against infection than the original version of the virus.
Given the weakening of protection seen in adult recipients and the rapid evolution of the virus, regulators said children who would receive Pfizer and Moderna vaccines are more likely to need a booster. This would mean that the Pfizer vaccine, developed with the German company BioNTech, can be obtained in four doses, while the Moderna vaccine can be three.
Both Pfizer-BioNTech vaccines and Moderna vaccines have provoked levels of neutralizing or blocking virus antibodies in children comparable to those in teenagers and young adults aged 16 to 25. The Pfizer vaccine has been approved for children ages 5 to 15 since last year, and regulators said it helped prevent hospitalizations and deaths.
After two doses, the Pfizer vaccine was about 28 percent effective in preventing symptomatic infection in children aged 6 months to 4 years. Pfizer estimates that the vaccine was 80 percent effective after the third dose, but the finding is based on only 10 cases from a subset of 1,678 study participants. The test report states that vaccine efficacy evaluations are based on at least twice as many cases; the small number of cases on which the finding of effectiveness is based was the subject of embarrassment among commission members and regulators on Wednesday.
Dr Doran Fink, senior federal vaccine regulator, called Pfizer’s efficacy data preliminary. “We consider it inaccurate and potentially unstable,” he said. “Exactly how effective the vaccine is after the third dose needs further data.”
Moderna found that its vaccine was 51% effective in preventing symptomatic infection in children aged 6 months to 2 years and 37% effective in children aged 2 to 5 years. These results appear to be consistent with those reported in adult studies during the Omicron era, the FDA said. However, immunization continues to offer strong protection against serious illness that leads to hospitalization and death.
Regulators and company employees spent part of the day discussing the side effects caused by vaccines. Most of them are mild and tolerated by children in clinical trials: irritability and crying, drowsiness, fatigue and loss of appetite. A small number of study participants had fever, but they were consistent with the effects of other pediatric vaccines.
In younger age groups, fever may be more debilitating and require more urgent medical attention, a dynamic that puts significant pressure on manufacturers to properly calibrate the dosage. Pfizer chose a dose of only one-tenth the strength of the adult dose given in three injections; the first two are applied at three-week intervals, with the third coming at least eight weeks after the second. Moderna uses a quarter of the strength of its adult dose given in two injections four weeks apart.
Some difficult questions remain. Importantly, no vaccine has been tested against subvariants circulating in the United States. Clinical trials were conducted to a large extent when the Omicron variant predominated. Two sub-options, BA.4 and BA.5, may become dominant within one month.
The need to protect these children from Covid is great, said Dr. Peter Marx, the FDA’s leading regulator of vaccines, at the meeting. He added that hundreds of children had died from Covid, a percentage he said “compared quite horribly” to pediatric deaths during the 2009 and 2010 flu spikes.
correction:
June 15, 2022
Due to an editing error, an earlier version of this article was incorrectly mentioned when the Pfizer-BioNTech vaccine was approved for different age groups in the United States. The vaccine is allowed for people aged 16 and over at the end of 2020, not in 2021, when vaccines are allowed for ages 5 to 15.
“Sharon LaFranier and Noah Wayland.”
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