The Centers for Disease Control and Prevention on Saturday recommended Covid vaccines for children as young as 6 months, who were among the last Americans to qualify for the shots. Parents should be able to start vaccinating young children as early as Tuesday.
Federal regulators have now approved the Moderna vaccine for children aged 6 months to 5 years, and the Pfizer-BioNTech vaccine for children aged 6 months to 4 years. (Pfizer-BioNTech vaccine has been available for children 5 years and older since November.)
All children 6 months and older, including those who have already been infected with the coronavirus, should receive a Covid vaccine, said Dr. Rochelle P. Walensky, CDC Director, in a statement.
“Together, with the science that leads the charge, we have taken another important stepforwardin our nation’s fight against Covid-19, she said. “We know that millions of parents and caregivers are eager to get their young children vaccinated, and with today’s decision, they can.”
Following meetings on Friday and Saturday, the agency’s scientific advisers strongly supported the vaccines, despite reservations about the lack of data, especially regarding the effectiveness of the Pfizer-BioNTech vaccine.
The CDC panel heard evidence supporting the effectiveness of the vaccines in the youngest children, but repeatedly pressured Pfizer on its estimates, noting that three doses of that vaccine would be necessary, compared with two doses of the Moderna vaccine.
Both vaccines are safe, and both produced antibody levels similar to those seen in young adults. But CDC advisers struggled with the difficulty of recommending two very different vaccines for the same population.
“Implementing these two rollouts is going to be incredibly challenging,” said Katelyn Jetelina, a public health expert and author of the widely read newsletter “Your Local Epidemiologist.”
“There has to be a lot of proactive communication about the difference between the two and the implications of taking one over the other,” she said.
In her clinical studies, Moderna found that two shots of the vaccine, each with a quarter of the adult dose, produced antibody levels that were at least as high as those seen in young adults.
The company estimated the vaccine’s effect against symptomatic infection at approximately 51 per cent among children aged 6 to 24 months, and 37 per cent among children aged 2 to 5.
The side effects were small, although about one in five children developed a fever. The effect against serious illness and death is assumed to be higher, similar to the effects seen in adults.
Based on these data, the FDA approved two shots of the Moderna vaccine, four weeks apart.
The Pfizer-BioNTech vaccine also gave a strong immune response, but only after three doses, company officials told the scientific advisers on Friday.
Two doses of the vaccine were insufficient, they said – and justified the FDA’s decision in February to postpone the approval of the vaccine until regulators had data on three doses. Two doses may not have been enough because the company gave children only one-tenth of the adult dose in each shot, some advisers said.
The vaccine has a total effect of 80 percent in children under 5 years, Pfizer’s researchers claimed on Friday. But that calculation was based on only three children in the vaccine group and seven receiving placebo, making it an unreliable calculation, CDC advisers noted.
“We should just assume we do not have efficacy data,” said Dr. Sarah Long, an infectious disease expert at Drexel University College of Medicine. But Dr. Long said she was “comfortable enough” with other data supporting the vaccine’s strength.
Three doses of the Pfizer vaccine produced antibody levels comparable to those seen in young adults, suggesting that it is likely to be just as effective.
“Pfizer is a three-dose series, but as a three-dose series it is quite effective,” said Dr. William Towner, who led vaccine trials for both Moderna and Pfizer at Kaiser Permanente in Southern California.
Each of the vaccines would be better than none, Dr. Towner added. He predicted that some parents may choose Moderna because it is easier to bring a child to a pediatrician for two injections than to make sure they get three.
The Pfizer vaccine was approved for children aged 5 to 11 in November, but less than 30 percent in that age group have received two injections. In surveys conducted by the CDC, about half of parents said in February that they would vaccinate their children, but by May, only a third of parents said they intended to do so.
Counselors discussed whether vaccination improves protection against serious illness in children who have already been infected. There is little information available from children aged 5 to 11 years, due to poor uptake of vaccines in that age group.
However, in adults, an infection with the former Omicron variant alone has not been enough to protect against the newer versions.
Vaccinations will still be needed to protect children from future variants, the experts concluded. “Combined protection is truly the safest and most effective,” said Dr. Sara Oliver, a CDC researcher who led the discussion on Saturday.
Parents of the youngest children may be more willing to choose a Covid vaccine if it can be offered along with other routine vaccinations, Dr. Towner said.
“This is the area that many people are not sure about right now,” he said. “I hope some guidance will be given on that.”