The Food and Drug Administration April 29 that it will reserve the dates June 8, 21 and 22 for its vaccine advisory committee to review the emergency use authorization requests of Moderna’s and Pfizer-BioNTech’s coronavirus shots for toddlers. While the dates remain subject to change, they provide an indication of when doses may be available to those under 5, as the FDA typically follows the recommendation of the committee in the weeks following its meeting.

Members of Congress sent a to the U.S. Food and Drug Administration Monday asking whether the agency intended to delay reviewing Moderna’s coronavirus vaccine for children 5 years old and younger and for “the scientific basis and any other rationale” for such an action.

The move comes after White House officials told last week that young kids, the last age group not yet eligible for coronavirus vaccines, will likely have to wait until the summer for immunizations — a longer timeline than previously expected.

Although Moderna completed the trial for its toddler vaccine in late March and submitted a on Thursday, Anthony Fauci said that the FDA is considering reviewing the pharmaceutical company’s application at the same time as Pfizer-BioNTech’s, which has not yet been submitted.

“[The] two products … are similar but not identical, particularly with regard to the dose. And what the FDA wants to do is to get it so that we don’t confuse people to say, ‘this is the dose. This is the dose regimen for children within that age group of 6 months to 5 years,'” President Biden’s chief medical advisor on Thursday.

“Such a decision could delay the potential authorization and administration of the Moderna vaccine by several weeks,” points out Rep. James Clyburn, chair of the House Subcommittee on the Coronavirus Crisis, in its letter to the FDA. The committee asked for a staff briefing on the subject by May 9.

In early February, Pfizer-BioNTech submitted data on a two-dose vaccine series for children under 5 to the FDA, but in a highly unusual move withdrew their application just 10 days later. The two shots, which are 10 times less potent than the companies’ adult doses, were safe for all age groups, but did not provide enough protection against the Omicron variant for 3- and 4-year-olds. Pfizer-BioNTech now plans to request that the FDA authorize a three-dose regimen for children under 5, the companies have said.

The Moderna series currently submitted for review includes two shots that are each one-quarter the dose adults received. Trial data showed shots to be 44% and 38% effective in preventing illness among children 6 months to 2 years old and 2 years to under 6 years old, respectively.

But despite the relatively low efficacy, many parents of young children are anxious for a base level of protection for their kids, especially as mask mandates and social distancing requirements continue to fall across the country. 

For some, the idea that the FDA would delay the Moderna shots on parents’ behalf — ostensibly to avoid confusion — struck the wrong chord.

“If I sign a waiver saying ‘I don’t find this confusing at all,” can I go ahead and get the vaccine for my four-year-old?” parent and New York Times writer Whet Moser .

Meanwhile, a Tuesday report from the Centers for Disease Control and Prevention revealed that more than half of Americans have been infected by the coronavirus, including . Rates of prior infection nearly doubled over the course of the Omicron surge, the agency found.

Jennifer Shu, an Atlanta-based pediatrician, agrees that if doses are ready for emergency use authorization, Washington should not delay the rollout. After all, vaccines from separate companies were approved at different times for other age groups, she pointed out.

“If it’s ready to go, if the science has proven that the vaccine is safe and effective, then why not let the parents educate themselves on it?” she told ����Ӱ��, adding that health professionals like herself can help families make an informed choice.

Parents of kids under 5 may feel they’re being “thrown under the bus” as pandemic precautions dwindle and the BA.2 Omicron subvariant threatens, said Shu.

But despite thousands of families eager to vaccinate their toddlers, still more are likely to pass on the opportunity when it becomes available. 

Immunization rates remain relatively low for older kids and teens with 28% of 5- to 11-year-olds and 58% of 12- to 17-years-old fully vaccinated as of April 20, according to the . New immunizations have slowed nearly to a halt, with vaccine coverage having increased only 1 percentage point in each age group since mid-March.

Even as vaccination rates are flatlining, Pfizer-BioNTech is planning to seek authorization for a third booster shot for kids 5- to 11-years old after trials found that it offers added protection against the Omicron variant.

On Friday, Pfizer-BioNTech that they will postpone their request that the Food and Drug Administration authorize their vaccine for children 6 months to 4 years old, saying they will wait for the data on a three-dose series. 

Three doses “may provide a higher level of protection in this age group,” the companies wrote.

In early February, Pfizer and BioNTech sent a rolling submission to the FDA for authorization of a two-dose round of shots, hoping to jumpstart the process of vaccines for little ones as early as the end of the month, while continuing to monitor whether a third dose may eventually be needed. But that timeline will now be halted until after researchers examine data from the three-dose regimen.

The FDA, in turn, pushed back its scheduled Feb. 15 advisory committee meeting to review the companies’ submission. 

“We will provide an update on timing for the advisory committee meeting once we receive additional data on a third dose,” said the federal agency in a .

Pfizer and BioNTech expect to have numbers on the efficacy of a third shot by early April, the companies said.

Younger children bear the lowest COVID risk out of all age groups and, even when unvaccinated, are less likely to fall seriously ill from the virus than vaccinated adults. But whiplash from the Friday announcement may frustrate many parents who were counting on the arrival of shots for some long-awaited relief after the Omicron surge brought on and widespread .

Health experts, too, expressed frustration with the sudden change in plans, worrying that it could undermine faith in the shots. 

“This rollercoaster that parents under 5 (including me) are forced to ride is an absolute, unacceptable disaster,” Katelyn Jetelina, assistant professor of epidemiology at the University of Texas School of Public Health, on Twitter. “Pfizer and the FDA need to get it together so the public knows what the (heck) is going on (and why) so we can continue to be confident in this process.”

Brown University’s Ashish Jha, on the other hand, : “This is good science in action. If we don’t yet have clear evidence of effectiveness, postponing a decision is the right thing to do.” He did, however, acknowledge “I know this will so disappoint parents of kids under 5.”

Pfizer-BioNTech shots for kids 6 months to 4 years old contain three micrograms of the vaccine, while the shots for teens and adults contain 10 micrograms and 30 micrograms, respectively.

Just under a quarter of children aged 5 to 11 and 56 percent of youth aged 12 to 17 are fully vaccinated against COVID-19, according to data from the .

The news comes as the number of average daily COVID cases in the U.S. has in the past two weeks, and as fears for spread of the Omicron variant have motivated a to a level not seen since late May. 

“With both the Delta and Omicron variants continuing to spread, vaccination remains the best protection against COVID-19,” said Acting FDA Commissioner Janet Woodcock in a .

The Omicron strain, listed as a “variant of concern” by the World Health Organization in late November, currently makes up a miniscule fraction of U.S. infections, but features a combination of mutations that worries scientists. It is known to have infected more than , the director of the Centers for Disease Control and Prevention told the Associated Press Wednesday.

The first look at how vaccines hold up against the Omicron variant bodes well for the efficacy of Pfizer-BioNTech’s booster doses, experts say. 

Lab data published Tuesday analyzing how effectively blood from vaccinated South Africans neutralized the new strain found that the virus did evade the immune defenses more craftily than previous versions of COVID. However, blood from individuals who had a previous infection and then received two vaccine doses did a good job staving off Omicron. It’s the best proxy so far for the immunity of those who have received three doses, scientists say, because South Africa has not yet authorized booster shots.

“​​This study gives me great hope that our boosters will help protect against Omicron,” Katelyn Jetelina, an assistant professor of epidemiology at the University of Texas School of Public Health, wote in a explaining the new lab results.

In authorizing third doses for 16- and 17-year olds, the FDA expanded its already existing emergency use authorization for the Pfizer-BioNTech vaccines to include older teens. Before shots can be officially administered to the newly eligible group, they need to receive the green light from the CDC, an authorization that is expected to come swiftly. The federal agency cleared boosters for all adults 18 and older in early November.

“Since we first authorized the vaccine, new evidence indicates that vaccine effectiveness against COVID-19 is waning after the second dose of the vaccine for all adults and for those in the 16- and 17-year-old age group,” said Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research. “A single booster dose of the vaccine for those vaccinated at least six months prior will help provide continued protection against COVID-19 in this and older age groups.” 

Meanwhile, as many Americans are still wrapping their minds around first, second and third doses, Pfizer CEO Albert Bourla said late Wednesday that the Omicron variant could mean will be necessary in under 12 months.

New Mexico appears to be the first state to require that certain workers receive booster shots, including a vaccinate-or-test rule for K-12 staff. So far, about 9 percent of school employees statewide have submitted documentation of having received a third dose.

Ensuring that staff and eligible students up their immunity as Omicron threats loom may be of particular importance given that temporary school closures have continued through the fall. Roughly 10 percent of the nation’s schools have experienced a disruption this school year alone. Some closures have been due to outbreaks, but others have been caused by teacher burnout and staffing shortages.

As of Dec. 1, some 4.3 million children ages 5 to 11, representing 15 percent of the age group, had received a vaccine dose. The same was true for ages 12 to 17, and over half had completed the full two-dose series, according to data published by the American Academy of Pediatrics.

Across all ages, more than people in the U.S are now fully vaccinated, about 60 percent of the population.

Centers for Disease Control and Prevention Director Dr. Rochelle Walensky on Tuesday evening the unanimous vote of a CDC vaccine advisory panel recommending Pfizer-BioNTech’s pediatric coronavirus vaccine for use in children ages 5 to 11. Her sign-off means shots can begin Wednesday for some 28 million children in this younger age group. The CDC approval comes after the Food and Drug Administration on Friday for emergency use in 5- to 11-year-olds. Children’s hospitals and pediatrician’s offices across the country told CNN that they have and would be ready to administer shots to children as soon as they got the green light. “As a mom, I encourage parents with questions to talk to their pediatrician, school nurse or local pharmacist to learn more about the vaccine and the importance of getting their children vaccinated,” Walenksy said.

Members of a federal advisory panel voted overwhelmingly Tuesday evening to recommend the authorization of a pediatric dose of Pfizer-BioNTech’s coronavirus vaccine for children ages 5 to 11, setting in motion a process that could make shots available for the age group by next week.

The 17-0 vote, with one abstention, represents a key step toward vaccine access for approximately 28 million U.S. children — and means that virtually all K-12 students could soon be eligible for shots.

The Food and Drug Administration panel endorsed giving children one-third the dosage for adults in two shots spaced three weeks apart. The group’s vote is non-binding, but the FDA typically in the days after a decision, according to The New York Times.

Next, the Centers for Disease Control and Prevention has Nov. 2 and 3 meetings scheduled for their own panel of experts to weigh in on the matter, after which emergency use authorization could soon be issued.

FDA committee members cast their votes after considering the efficacy data of the Pfizer-BioNTech shots and the cumulative toll of COVID-19 on children and families.

Shots for kids were 91 percent effective at preventing infection, the pharmaceutical companies’ trial showed. Only three out of over 3,000 inoculated children experienced breakthrough infections, compared to over a dozen who had received the placebo.

Immunity and side effects for 5- to 11-year-olds were comparable to those produced by the larger dose in 16- to 25-year-old patients, the data showed. No new safety problems or cases of heart inflammation were observed in the trial. Israeli studies have found myocarditis to occur in less than , so it’s possible the condition would have been too rare to have been detected in the main study.

However, even in worst-case scenarios where adverse cases run on the high side of what officials expect, the benefits of shots for kids still supersede the potential dangers, according to modeling presented by Hong Yang, senior advisor at the FDA’s Office of Biostatistics and Epidemiology.

“The benefits clearly outweigh the risks,” she said.

Over the course of the pandemic, nearly 2 million children between the ages of 5 and 11 have fallen ill with the virus, 8,300 have been hospitalized, and close to 100 have died, making COVID-19 one of the top 10 causes of death among the age group, said Peter Marks, who heads the FDA division that oversees vaccine approvals.

In addition to preventing cases and hospitalizations, minimizing learning disruptions was a key consideration for advisory committee members. 

Since August, over 1 million K-12 students have been affected by school closures due to COVID, Dr. Fiona Havers, a viral diseases specialist at the CDC told committee members during the Tuesday hearing.

“The school closures and the disruption has been enormous,” said the FDA’s Jeanette Lee. “We have to weigh that against the benefits we would see [from] the vaccine.”

Randi Weingarten, president of the American Federation for Teachers, celebrated the panel’s recommendation as a win for school safety.

“This is huge news in our ongoing effort to keep our kids safe from COVID-19. For nearly two years, parents have been living in fear, worried that their child could get sick at school, day care, or in daily life, but now they finally have FDA-approved protection to add to the long list of vaccines we use to keep our children protected from transmissible diseases,” she said in a statement. “Educators, school staff and healthcare professionals are eager to work together with parents to help get America’s kids vaccinated in the places they trust, including public schools and community centers.”

At least one committee member, Cody Meissner, who ultimately voted to recommend the vaccine for authorization, expressed hesitation about how greenlighting shots for 5- to 11-year-olds may play out for school policy. 

“I’m just worried that if we say yes, that the states are going to mandate administration of this vaccine to children in order to go to school and I do not agree with that. I think that would be an error at this time,” he said during the Tuesday hearing.

Vaccine mandates have become a flashpoint in the ongoing culture wars now consuming school boards nationally. Only a handful of school districts, mostly in California, have enacted coronavirus vaccine requirements for eligible students. The Golden State’s two largest school systems, Los Angeles and San Diego, are currently defending their policies in court. 

California is also the only state to mandate shots for eligible students, though the policy will .

A third of parents with children ages 5 to 11 said they would get their child vaccinated “right away” once they were eligible, according to a Sept. 30 , while a third said they would “wait and see” and a quarter said they would “definitely not” vaccinate their younger children. A by ​​the COVID-19 Vaccine Education and Equity Project reported that two-thirds of parents with children in the age group said they would immunize them once the shots are authorized.

When shots do ultimately roll out for children, vials will be colored differently to avoid confusion with the more potent adult formula, said William Gruber, senior vice president of Pfizer Vaccine Clinical Research and Development.

Immediately after the FDA panel’s vote, Ashish Jha, dean of the Brown University School of Public Health, .

“They got it right,” he said.

The protection provided by the shots, the companies say, supports authorization of the vaccine for the 28 million U.S. children in that age group. The Food and Drug Administration has a hearing scheduled Tuesday with expert advisors to review the case for authorization. 

Two weeks ago, Pfizer and BioNTech submitted their formal request to the FDA for the green light to deliver doses to 5- to 11-year olds. 

If the review timeline spans a similar length as that of vaccines for 12- to 15-year olds, the agency could grant authorization ahead of the Thanksgiving holiday — meaning that the vast majority of K-12 students may soon be eligible for immunizations.

The vaccine efficacy numbers come from a Pfizer and BioNTech provided to the FDA, released Friday morning by the federal agency. In their trial, the companies tested a 10 microgram dose of the vaccine, one-third the size of the shot for teenagers and adults, and found that it produced a “robust” antibody response. Immunity and side effects, they said, were comparable to those produced by the larger dose in 16- to 25-year-old patients. 

No new safety problems or cases of heart inflammation were observed in the trial, which tested 2,268 participants. Israeli studies have found myocarditis to occur in , so it’s possible the condition would have been too rare to have been detected in the main study. 

The news comes as children make up over , amounting to about a quarter of all reported infections per week nationwide, according to mid-October data published by the American Academy of Pediatrics. Over have closed so far this year due to outbreaks of the virus, according to Burbio, an organization that has tracked schools through the pandemic, though COVID-related school closures have slowed considerably in recent weeks as and schools hone their protocols to curb spread.

The White House has made it clear that immunizing children will be a priority once shots are authorized for 5- to 11-year olds. The Biden administration will match schools with COVID-19 vaccine providers, the White House Wednesday. The Department of Health and Human Services will also enlist community-based clinics, doctor’s offices, hospitals and faith-based organizations in rapidly distributing vaccines.

Two-thirds of parents of children aged 5 to 11 years say they will immunize their children against COVID-19 once shots are authorized for the age group, according to by the COVID-19 Vaccine Education and Equity Project.

“While we’re encouraged to see that a majority of parents intend to vaccinate their children against COVID-19 once they are eligible, there is clearly more work to be done to help address parents’ questions and ease concerns about the vaccines,” Beth Battaglino, CEO of the nonprofit HealthyWomen, one of the partner organizations behind the polling, said in a .

Pfizer-BioNTech vaccinations have been fully approved by the FDA for individuals ages 16 and above, and have emergency use authorization for teenagers ages 12 to 15. Shots for kids younger than five may arrive .