CDC’s Advisers Endorse COVID Vaccines in Youngest Kids

CDC’s Advisers Endorse COVID Vaccines in Youngest Kids

June 18, 2022 0 By Jennifer Walker

The CDC’s Advisory Committee on Immunization Practices (ACIP) voted unanimously on Saturday to recommend that children 6 months and older receive COVID-19 vaccines.

As proposed by CDC staff, and now approved by CDC Director Rochelle Walensky, MD, MPH, the recommendations call for a two-dose series of Moderna’s product for children ages 6 months to 5 years, and a three-dose series for Pfizer-BioNTech’s in those 6 months to 4 years.

The vote tallies were 12-0 for both products, and the recommendations follow the FDA’s decision on Friday to grant emergency use authorization to the two mRNA vaccines for these age groups.

“We don’t know what’s coming, but I’m confident that this will be a net benefit,” ACIP member Oliver Brooks, MD, of Watts HealthCare Corporation in Los Angeles, said after the votes.

Even before starting the second day of ACIP’s 2-day meeting, it was apparent that members were already poised to expand COVID-19 vaccination recommendations to this younger group. Discussions and questions showed no skepticism that either vaccine would not protect infants and young children against severe outcomes such as hospitalizations and multisystem inflammatory syndrome in children (MIS-C).

Rather, ACIP members seemed most concerned that the CDC do all it can to craft messaging to encourage uptake by parents, among whom surveys show considerable hesitation.

CDC staff shared data with the committee indicating that roughly one-third of parents with children younger than 5 “definitely or probably” would not let their kids be vaccinated at all, and many of the others wouldn’t do so right away after they become eligible. Only 20% were ready to have their young children vaccinated within 3 months of availability.

This despite a sheaf of evidence that COVID-19 is a serious concern for infants and preschoolers. Epidemiological data show that COVID has become the fourth or fifth leading cause of death in this age group. More children have died from COVID during the pandemic compared to other vaccine-preventable diseases (e.g., varicella, rubella, rotavirus) in the years before vaccines became available for those diseases.

Several panelists bemoaned that they keep hearing from parents that COVID-19 isn’t a serious problem for young kids.

One ray of hopeful light is that the surveys also showed that parents feel uninformed about the benefits and risks of COVID vaccination, and also that their pediatricians are their most trusted source of information. The CDC is developing new outreach efforts to physicians who may then relay to parents their confidence that vaccination is a good idea. Surveys of pediatricians indicate broad willingness to be part of an expanded vaccine rollout, with half even saying they would vaccinate children who are not their regular patients.

Other details on the recommendations for the new age group included:

  • Moderna’s product will be formulated to deliver two 25 mcg doses, given 4 weeks apart
  • For Pfizer-BioNTech’s, the dosage is 3 mcg of mRNA per shot; the second given 3 to 8 weeks after the first (depending on patients’ circumstances), and the third 8 weeks later

Each will come in 10-dose vials with a new cap color to distinguish from the companies’ vaccines for older ages.

Some ACIP members initially expressed concern that 10 doses is too many, given the products’ brief usability after vials are opened. But a CDC official countered that physicians should focus on the overarching public health problem, which is that young children need protection against COVID-19 and are now unvaccinated.

“There is sufficient vaccine, and we understand that as pediatricians, as primary care givers, we have been very averse to wastage in the past,” José R. Romero, MD, director of the agency’s National Center for Immunization and Respiratory Diseases, told the panel.

“There will be wastage, we understand that,” he continued. “But it’s important to get shots into arms and take advantage of every opportunity. We will have to do a reset of this core principle of ours, and don’t worry about opening a vial to administer two doses.”

To be sure, ACIP members saw plenty of efficacy and safety data from the trials conducted by Moderna and Pfizer. These supported the view that the products do prevent infections, with relatively low rates of serious adverse effects.

Given that the trials were conducted largely during the Delta and Omicron waves, when the virus’s infectivity appeared to jump dramatically relative to earlier variants, the efficacy numbers were considerably lower than those from the initial adult trials in 2020. For Moderna’s product, vaccine efficacy in these young kids was put at 37-40.3% depending on which definition of infection was used; Pfizer’s corresponding numbers were 76.2-81.5%, although officials cautioned against comparing the two because of the many differences in trial methods.

There were other holes in the trial data as well. Pfizer did not seek to analyze efficacy for preventing hospitalization or other severe outcomes, and its trial began with a two-dose series, such that only a fraction of participants received the three doses that are now recommended. When the sponsor’s data were presented on Friday, ACIP chair Grace Lee, MD, of Stanford University in California, commented that she was “challenged” that administering three doses wasn’t the plan from the beginning.

Likewise, although the CDC is likely to recommend special dosing regimens for immunocompromised infants and preschoolers, Moderna’s study didn’t look at that population.

Perhaps most significantly, the trials were conducted before the newest SARS-CoV-2 variants began spreading. Thus, the vaccines’ effectiveness against them is anyone’s guess.

But that didn’t seem to bother ACIP members. Those who spoke to the topic argued that past experience in older age groups, data on antibody responses collected in the trials, and general virology principles make it virtually certain that the vaccines will prevent severe infections, if not reinfections. “It doesn’t do us a lot of favors” to dwell on numerical efficacy data, said Yvonne Maldonado, MD, the American Academy of Pediatrics’ liaison to ACIP, given what is already known about vaccines in general.

Indeed, member Sarah Long, MD, of St. Christopher’s Hospital for Children in Philadelphia, commented that the messaging should focus on the inevitability of reinfections. She noted that all respiratory viruses, such as those causing common colds and influenza, offer little to no immunity after infection.

“Don’t talk about ‘breakthrough’ infections,” she urged. “Reinfections are expected, not a failure of vaccines.”

One issue that did trouble the committee involved labeling on the Pfizer-BioNTech product. The FDA-authorized instructions say that it should be discarded 6 hours after diluent is added. But the CDC is planning to advise that 12 hours can elapse. ACIP members expressed concern that this would surely cause confusion.

Amanda D’Ambrosio contributed reporting to this article.