The Centers for Disease Control and Prevention’s scientific advisers will meet on Saturday to decide whether the benefits of the Covid vaccine outweigh the risks to children under 5, the last of Americans. eligible for vaccination.
The meeting, which will be streamed live here, is scheduled to begin at 10 a.m. Eastern time. All advisors are guaranteed to vote yes, although there are reservations about the paucity of data, especially regarding the efficacy of the Pfizer-BioNTech vaccine.
Earlier this week, another group of experts advising the Food and Drug Administration unanimously supported the vaccine. On Friday, the FDA approved the Moderna vaccine for children 6 months to 5 years old and the Pfizer vaccine for children 6 months to 4 years old. (Pfizer-BioNTech’s vaccine has been available to children 5 years of age and older since November.)
On Friday, CDC advisers heard evidence supporting the vaccine’s effectiveness in the youngest children. But the committee repeatedly pressed Pfizer on its estimates, noting that three doses of the vaccine are needed to protect children, compared with two doses of the Moderna vaccine.
Both vaccines were safe and both produced antibody levels similar to those seen in young people. If Saturday’s commission’s confirmation is quickly given the green light by agency director Dr Rochelle Walensky, states are gearing up to begin vaccinating children next week.
Among the tasks facing the CDC panel on Saturday was the difficulty of recommending two very different vaccines for the same population.
“It will be extremely difficult to do these two rollouts,” said Katelyn Jetelina, a public health expert and author of the widely read newsletter “Your Local Epidemiologist.”
“It will take a lot of initiative to talk about the difference between these two factors and the impact of taking advantage of one over the other,” she said.
In its clinical trials, Moderna found that two shots of its vaccine, one-quarter of an adult dose, produced antibody levels at least as high as those seen in young people.
The company estimates the vaccine’s effectiveness against symptomatic infections at about 51% in children 6 to 24 months and 37% in children 2 to 5. Side effects are minor, although approximately 1/5 of children have a fever.
Based on those data, the FDA authorized two doses of the Moderna vaccine, four weeks apart.
Company officials told scientific advisers Friday that the Pfizer-BioNTech vaccine also produced a strong immune response, but after only three doses.
They say two doses of the vaccine are not enough – justifying the FDA’s decision in February to delay vaccine authorization until regulators have data regarding three doses. Some advisers say two doses may not be enough because the company only injects children with 1/10 of the adult dose in each injection.
Pfizer scientists claim that the vaccine is 80% effective overall in children under 5 years of age. However, that calculation was based on only three children in the vaccine group and seven children given a placebo, making it an unreliable metric, the CDC advisors note.
“We should just assume we don’t have efficacy data,” said Dr Sarah Long, an infectious disease specialist at Drexel University College of Medicine. But Dr Long said she was “comfortable enough” with other data supporting the vaccine’s effectiveness.
Three doses of Pfizer vaccine produced antibody levels comparable to those seen in young adults, suggesting that it is likely to be equally effective.
“Pfizer is a three-dose series, but as a three-dose series, it’s pretty effective,” said Dr William Towner, who leads vaccine trials for both Moderna and Pfizer at Kaiser Permanente in Southern California.
Dr. Towner added, if a vaccine would be better than nothing. He predicts that some parents may choose Moderna because it’s easier to take their child to the pediatrician for two shots than it is to arrange for three.
The Pfizer vaccine was approved for children ages 5 to 11 in November, but less than 30 percent of that age group received two shots. Parents of the youngest children may be more willing to opt for a Covid vaccine if it can be given alongside other routine immunizations, Dr. Towner said.
“It’s an area where a lot of people aren’t sure about it right now,” he said. “I hope there will be some guidance provided around that.”
