CDC and FDA clear the way for COVID vaccines for kids under 5
Some 20 million babies, toddlers, and preschoolers are now eligible to be vaccinated for COVID-19, after the Centers for Disease Control and Prevention's Director Dr. Rochelle Walensky signed off on unanimous votes from her agency's outside vaccine advisers to recommend shots from Moderna as well as Pfizer and BioNTech for children as young as six months old.
"Together, with science leading the charge, we have taken another important step forward in our nation's fight against COVID-19," Walensky said in a statement.
Around a third of parents say they plan to get their child in the age group vaccinated, according to CDC survey findings released on Saturday. Some of the long-awaited shots could begin as soon as this holiday weekend. Federal officials expect the bulk of vaccinations will commence after doctor's offices reopen on Tuesday.
"We know millions of parents and caregivers are eager to get their young children vaccinated, and with today's decision, they can. I encourage parents and caregivers with questions to talk to their doctor, nurse, or local pharmacist to learn more about the benefits of vaccinations and the importance of protecting their children by getting them vaccinated," added Walensky.
The CDC's Advisory Committee on Immunization Practices voted following a two day-long meeting to mull data on the benefits and risks of the shots in young children. A panel of the Food and Drug Administration's own outside advisers had also voted unanimously on Wednesday to back authorization.
"Those trusted with the care of children can have confidence in the safety and effectiveness of these COVID-19 vaccines and can be assured that the agency was thorough in its evaluation of the data," FDA Commissioner Dr. Robert Califf said in a statement.
The FDA also moved on Friday to add Moderna's vaccine as an alternative to Pfizer's shots in children 6 through 17 years old, though the CDC said their advisers will not vote on updated recommendations for those shots until next week.
Distributing the initial waves of shots
Shipments have already begun of the vaccines from Moderna as well as Pfizer and their partner BioNTech, after the Food and Drug Administration issued authorization on Friday. However, as with older age groups, the government's supply agreements require vaccinators to wait for the CDC's sign-off before administering shots for young children.
Federal officials say most jurisdictions— except for Florida — had pre-ordered doses out of the 10 million total shots that were made available; 2.5 million orders were received for Pfizer's shots and 1.3 million for Moderna's.
Many of those will head to places picked out by authorities, like county health departments, which are able to stockpile and redistribute smaller helpings of the 100-dose shipments. States, including Florida, have now also begun allowing all enrolled vaccinators to directly request shots through them.
Some drug stores will also offer the shots, though authorities have been planning a rollout that will lean heavily on pediatricians and family doctors over the coming weeks. Pandemic liability protections extended to vaccinators like pharmacists only cover children as young as three years old.
The Biden administration's Vaccines.gov website will also soon include a feature to search for sites specifically offering shots for younger children as more vaccinators begin offering shots. Around half of doctors who vaccinate children are planning to offer shots even to kids who are not their regular patients, a CDC survey found.
Providers in the initial wave have ordered only one of the brands in some jurisdictions, though the Biden administration hopes that will even out as supply climbs around the country over future rounds of shipments.
Smaller doses for kids - and the differences between Moderna and Pfizer
Unlike the largely similar regimens of the first round of COVID-19 shots that were available in adults, the makers of the two mRNA vaccines have taken different approaches to immunizing young kids.
In children ages 6 months to 5 years old, Moderna's vaccine was trialed as two shots spaced one month apart. Their doses will be 25 micrograms, a fraction of the 100-microgram primary series rolled out last year for adults.
Pfizer and BioNTech's vaccine will come in a total of three shots administered over the course of 11 weeks, for children ages 6 months through 4 years old. Those doses are sized at 3 micrograms, just one-tenth of the 30-microgram shots for those 12 and older.
At a briefing with reporters on Friday, the FDA's top vaccines official Dr. Peter Marks acknowledged the "nuanced benefits and risks compared to each other" but urged parents to seek out the first shots available to them.
"It may be that the Moderna vaccine brings an immune response slightly more rapidly. On the other hand, the three dose Pfizer regimen may also bring a greater immune response after the third dose. And there are some subtle differences in the safety profile," Marks said.
Based on studying antibodies against the virus in blood drawn from trial participants, the FDA said data in the young children suggests their immune response will be at least as good as the one seen in adults after they had received their first two shots.
Some of the children under 5 years old did not clear this threshold after receiving only two of their doses in Pfizer's trials, the company disclosed to investors last year, so a third dose was required.
"If you want to put your child back in daycare or lower school in September, you have to take the Moderna vaccine. You cannot do it on Pfizer's schedule. And we know that two doses does not protect, from Pfizer," Moderna's CEO Stéphane Bancel said last week at the Jefferies Healthcare Conference.
The FDA's review noted that Pfizer's smaller dose likely resulted in the lower side effects seen in the group compared to older ages.
"We already know that, in older individuals, 30% of children are getting the vaccine. There could be a lot of reasons for that, but one of them is the reactogenicity," William Gruber, Pfizer's head of vaccine clinical research and development, told the FDA's advisers, referring to short-term side effects like aches, fever and pain at the injection site.
For Moderna, rates of fever were higher in younger kids compared to adolescents and adults, though still around levels seen in this age group with other routine vaccines, the FDA's review noted.
Pfizer's estimate for vaccine efficacy of three doses in fending off symptomatic infection is also much higher than Moderna's estimate for two doses during the Omicron wave, as well as better than those seen in some older age groups who received Pfizer's doses.
But both the FDA and CDC's reviews raised questions over Pfizer's estimate, suggesting it was too early to say for sure exactly how effective the three doses will be and cautioning against direct comparisons. Some trial participants also received their third Pfizer shots far later than the recommended eight weeks, the FDA noted.
In its release on Friday announcing the authorizations, the FDA said Pfizer's analysis "was determined not to be reliable due to the low number of COVID-19 cases that occurred in study participants."
"I believe the vaccine is effective. I do not have any idea what that number will actually end up being," the CDC's Dr. Amanda Cohn told the FDA's committee on Wednesday.
When will younger kids get a booster
Marks acknowledged both vaccines may need to be updated over the coming months, but urged parents to begin offering their kids a "foundational level of immunity" with current versions of the shots now.
The FDA has another meeting of its advisers scheduled to weigh the topic for all ages, as both vaccinemakers have raced to ramp up production of new formulations of their shots designed to target the Omicron variant.
"If it turns out that there is a very major change in strains that needs to occur in the fall, we will adjust for that and make sure that there is an option available for the youngest children and throughout the pediatric age range as appropriate," Marks said.
A Moderna executive told the CDC's advisers on Friday that the company is already planning to begin studying boosters adapted for the Omicron variant in children under six starting next week, given at least three months after their second dose.
"We hope by early fall we'll be able to bring forward the booster immunogenicity and safety data for this age group," Moderna's Dr. Rituparna Das told the CDC's committee.
Children six months and older are already authorized by the FDA to get a third dose of Moderna's vaccine, if they are significantly immunocompromised.
Younger children are generally at lower risk of severe COVID-19 compared to their older peers and adults, and many asymptomatic cases have likely gone unreported. No severe cases of the disease were recorded in Moderna's trial, even among children who had gotten a placebo.
However, officials and experts warn that the virus has still inflicted an unprecedented toll on children.
"There is a lot of information circulating that, well, 'I had the Omicron variant, or my child had the Omicron variant, and vaccination is not important,'" Marks said Friday.
During the Omicron wave, hospitalizations and deaths in young kids surged despite data suggesting many children already had some antibodies from a prior infection.
"There are emerging data to suggest that the Omicron variant does not produce the kind of excellent immune response against a wide range of COVID-19 variants that the vaccinations do," he added.