CDC Director Endorses COVID Vaccines for Infants and Toddlers CDC Director Endorses COVID Vaccines for Infants and Toddlers

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COVID-19 vaccines for children 6 months to 5 years of age are now ready to go. Centers for Disease Control Prevention (CDC) Director Rochelle Walensky, MD, has endorsed a unanimous recommendation by the agency’s vaccine panel today, allowing vaccinations to begin as early as this week.

“Together, with science leading the charge, we have taken another important step forward in our nation’s fight against COVID-19. 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,” Walensky said in a prepared statement.    

Earlier today, the CDC’s Advisory Committee on Immunization Practices (ACIP) voted 12-0 to recommend use of the Moderna COVID-19 vaccine in children 6 months to 5 years of age, as well as a vote of 12-0 to recommend use of the Pfizer/BioNTech vaccine in children aged 6 months to 4 years.

The US Food and Drug Adminstration authorized the vaccines on Friday in children as young as 6 months of age, soon after its advisory panel also unanimously recommended the shots earlier this week.

Parents and caretakers now have the all-clear to start vaccinating these youngest of Americans, with the shots expected to start this week.

That is a sigh of relief for millions of parents who have been anxiously waiting for this approval for their youngest children. Medical groups, from the American Academy of Pediatrics (AAP) to the American Medical Association (AMA), applauded today’s decision.

“Authorization of the Moderna and Pfizer-BioNTech vaccines for children ages 6 months and older will extend the protection of immunization to the last segment of our population awaiting protection. More work remains to vaccinate older children and adolescents, as well. As of June 8, more than 23 million children ages 5 to 17 have received two doses of COVID vaccine. Another 26 million in this age group have yet to receive any doses,” the AAP said in a prepared statement.  

“We must not let up in our efforts to make sure all families can benefit from the protection of these vaccines,” said AAP President Moira Szilagyi, MD, PhD.

The AAP published its updated recommendations soon after today’s ACIP vote.

The AMA joined the AAP in its support for vaccinating young children.

“According to the CDC, COVID-19 is a leading cause of death among children ages 0-19 years. Since the beginning of the pandemic, among children in the US aged 6 months to 4 years, there have been more than 2 million cases of COVID-19, more than 20,000 hospitalizations, and more than 200 deaths. We urge parents to get their children vaccinated against COVID-19 as soon as they are eligible. While there is overwhelming scientific evidence showing the COVID-19 vaccines are safe and effective, we know many parents and families still have questions,” Jack Resneck Jr, MD, president of the American Medical Association, said in a prepared statement

The CDC panel vote in favor of both mRNA COVID-19 vaccines in this age group came after 2 days of deliberation by scientists, clinicians, and other experts participating in the advisory committee.

The Moderna vaccine emergency use authorization (EUA) is based on two 25 µg intramuscular primary doses (one fourth the adult dose) separated by 1 month. The Pfizer vaccine is authorized as a three-dose primary series administered as 3 µg each (one tenth the adult dose). The authorized Pfizer vaccine dosing is 21 days between dose 1 and dose 2, followed by 60 days between dose 2 and dose 3.

Representatives from Moderna and Pfizer/BioNTech reviewed the evidence for safety and efficacy of their products during the ACIP meeting.

Moderna Study 204 data, for example, revealed a 50.6% efficacy in infants and toddlers age 6 months to 23 months and a 36.8% efficacy in children 2 years to 5 years old, using a CDC definition of effectiveness. The total number of children 6 months to 5 years in the efficacy and safety evaluation was 6400, including 4800 who received the vaccine and 1600 who received a saline placebo.

This level of efficacy “is consistent with adult effectiveness against Omicron,” said Rituparna Das, MD, PhD, vice president for vaccines at Moderna.

The antibody levels after two doses of the Moderna vaccine in the 6 month to 5-year-olds was similar to levels observed in individuals 18 to 24 years. Similarly, the antibody levels after three doses of the Pfizer vaccine were similar to those seen in people ages 16-24 years old.

Some Confusion Around Pfizer Data

The Pfizer numbers generated some questions from ACIP experts, many of whom indicated they were “confused” by how the company presented the data.

In particular, the reported efficacy of 80.3% was based on a limited number of cases, namely three children out of 992 who developed symptomatic COVID-19 in the vaccine group. Another seven children out of 464 in the placebo group were symptomatic.

The 95% confidence interval for the 80.3% efficacy number was 13.9% – 96.7%.

ACIP members also wanted more information on why the Pfizer primary series includes three vaccine doses.

“As demonstrated in other pediatric and adult age groups, two doses of BNT162b2 are protective against variants of concern such as Delta, but do not provide adequate protection against Omicron,” said William Gruber, MD, senior vice president of Pfizer Vaccine Clinical Research and Development.

“A third dose is necessary to provide high protection against Omicron,” he said. “Protection against COVID-19 is critical, particularly given the unpredictability of future waves or emergence of new variants.”

Regarding the Pfizer numbers, “efficacy estimates are difficult to interpret given the small numbers and limited follow-up time,” said Sara Oliver, MD, MSPH, lead of the ACIP COVID-19 Vaccines Work Group at the CDC. The median follow-up in the Pfizer data was 1.3 months.

Gruber noted that the ‘immunobridging’ data supports the efficacy of the Pfizer vaccine. Immunobridging is a way to infer efficacy by assessing immune markers and comparing them to efficacy already demonstrated in another group, in this case older vaccine recipients.

Because of the differences in the studies submitted for authorization, the efficacy of the two vaccines should not be directly compared to each other, but rather considered as each vaccine vs placebo, Oliver said.

The Work Group had “higher confidence” in the Moderna efficacy estimates because of the higher number of symptomatic cases and “lower confidence” regarding the Pfizer efficacy given the lower case numbers, she said.

When Pfizer’s Gruber was asked about future efficacy studies, he responded, “We will have additional cases to give us more precision on these numbers…not just efficacy but durability too.”

Fever, Other Safety Considerations

Pain was the most common local reaction reported in children up to age 5 years in the Moderna vaccine research. Most symptoms were mild and lasted 2 to 3 days. In terms of systemic adverse reactions, fever, irritability, crying, sleepiness, and loss of appetite were most common in the 6 months to under-2 year group. In children aged 2-5 years, fever, headache, fatigue, myalgia, nausea, vomiting, and chills were most common.

There was one febrile seizure reported 3 days after a first dose, a reaction that the study investigator considered related to the vaccine in the Moderna study. “Approximately 6 weeks later, the child has remained in the study and received two doses of the vaccine without [further] events.”

There were no cases of myocarditis or deaths reported in the Moderna or Pfizer studies.

Pain or tenderness at the injection site were the most common local reactions in the Pfizer study. In terms of systemic reactions, irritability and drowsiness were more common in children 6 months to under 2 years. Fatigue was most common in children ages 2 to 4 years. Most symptoms were mild and resolved within 1 to 2 days.

Fevers also were reported in the Pfizer trial, most lasting a median of 1 day and at a frequency similar to fevers seen in the placebo group.

Unanswered Questions

Post-authorization studies of effectiveness could help figure out the need and timing for booster doses of either vaccine, Oliver said.

Moderna’s Das noted that future booster studies in young children may include the Moderna bivalent vaccine in development, which includes a strain of the vaccine specifically designed to target Omicron.

A BabyCOVE study will be started, she added, looking at even younger children, 3 months to 6 months of age, including babies born prematurely.

ACIP experts also asked about concomitant vaccines. Both Moderna and Pfizer trials separated other vaccinations by either 2 or 4 weeks around immunization with the COVID-19 vaccines.

So it remains unknown whether the COVID-19 can be given at the same time as other vaccines in infants, toddlers, and young children. Future studies are planned by both manufacturers to look at combining the COVID-19 vaccine with other immunizations.

In addition, guidance on administering either vaccine in moderately or severely immunocompromised children in the 6 month to 5 year old group, including any additional doses and their timing, remains unknown.

More Guidance Available

Parents and caregivers interested in immunizing their young children should consult vaccines.gov to find nearby locations with vaccines available for this age group, said Kevin Chatham-Stephen, MD, MPH, lead of the pediatric vaccine planning and implementation for the CDC Vaccine Task Force.

A forthcoming ‘Quick Conversation Guide’ being developed by ACIP in partnership with the American Academy of Pediatrics, he added, should assist clinicians in addressing questions and comments regarding COVID-19 vaccines from parents and caregivers.

Based on a meeting of the CDC Advisory Committee on Immunization Practices.

Damian McNamara is a staff journalist based in Miami. He covers a wide range of medical specialties, including infectious diseases, gastroenterology, and neurology. Follow Damian on Twitter:  @MedReporter.

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